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Sample records for bimorph cantilever-actuated peristaltic

  1. Type Inference for Bimorphic Recursion

    CERN Document Server

    Tatsuta, Makoto; 10.4204/EPTCS.54.8

    2011-01-01

    This paper proposes bimorphic recursion, which is restricted polymorphic recursion such that every recursive call in the body of a function definition has the same type. Bimorphic recursion allows us to assign two different types to a recursively defined function: one is for its recursive calls and the other is for its calls outside its definition. Bimorphic recursion in this paper can be nested. This paper shows bimorphic recursion has principal types and decidable type inference. Hence bimorphic recursion gives us flexible typing for recursion with decidable type inference. This paper also shows that its typability becomes undecidable because of nesting of recursions when one removes the instantiation property from the bimorphic recursion.

  2. Polymer constraint effect for electrothermal bimorph microactuators

    NARCIS (Netherlands)

    Chu Duc, T.; Lau, G.K.; Sarro, P.M.

    2007-01-01

    The authors report on the analysis of the polymer constraint effect and its use for a micromachined electrothermal bimorph actuator. The actuated displacement is enhanced due to the polymer constraint effect. Both the thermal expansion and apparent Young’s modulus of the constrained polymer blocks a

  3. Multi-path peristaltic pump

    Science.gov (United States)

    Chandler, Joseph A. (Inventor)

    1986-01-01

    The instant invention is directed to a peristaltic pump for critical laboratory or hospital applications requiring precise flow rates over an extended period of time. Within the cylindrical barrel pump housing is a single-piece, molded, elastometric, cylindrical liner with a multiplicity of flattened helical channels created therein from one end of the liner to the other. Three cylindrical rollers rotate about the center axis of the pump around the inside surface of the liner selectively compressing the liner, and hence the helical channels between the rollers and the barrel housing, creating a pumping action by forcing trapped fluid in the helical channels axially from one end of the liner to the opposite end. The novelty of the invention appears to lie in the provision of the special liner with multiple helical channels as the pumping chamber, rather than the standard single elastomeric tubing which is squeezed repeatedly by rollers to move the liquid through a typical peristaltic pump. Large, repeated deflections on the standard tubing causes a permanent set in the tubing, thus either changing the flow rate, or requiring a new section of tubing to be positioned in the pump head. Further, this configuration minimizes the amount of outflow pulsation which is characteristic of a typical single tubing peristaltic pump.

  4. TRAVELING MACHINE DRIVEN BY PIEZOELECTRIC BIMORPH

    Institute of Scientific and Technical Information of China (English)

    HUA Shunming; CHENG Guangming; FAN Zunqiang; YANG Zhigang; SUZUKI Katsiyoshi

    2007-01-01

    A rectangular bimorph will vibrate in bending mode under alternating current (AC) electric field. If two opposite tips along longitudinal direction are both clamped, the maximum magnitude of bending displacement occurs on the short center line. Using bimorph type vibrators forementioned as actuators, an invention of simple traveling machine based on stick-slip principle is presented. The machine can not only move along both x and y direction within horizontal working plane, furthermore, excellent bearing ability and agile response as well as stable step are also proved. In addition, the machine can work on stepping mode and scanning mode at the same time, hence the contradiction between long stroke and high precise positioning is solved. Therefore, it meets the needs of micro/nanometer precise positioning under long stroke and is desired to be used as carrying stage for micro-assembling system and locomotive mechanism for miniature robot system.

  5. Performance analysis of piezoelectric bimorph generator

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this paper,the theoretical model and simulation of the performance of a piezoelectric (PZT)bimorph generator is introduced.The generator consists of two piezoelectric plates bonded on a substrate metal plate.For an effective electromechanical coupling coefficient (EECC) and the generated energy,the analytical formulae are established with the thickness ratio and the Young's modulus ratio as variables.After giving correlative material parameters,the EECC and generated energy can be computed.The results show that there is a optimal thickness ratio for a piezoelectric bimorph generator to achieve the maximum EECC and electrical energy.The EECC and generated energy decrease with an increase of the Young's modulus ratio.In addition,the influence of mechanical source on electrical energy generation and power output is also considered.

  6. BIMORPH PIEZOELECTRIC ACTUATOR FOR SMALL PIPE ROBOT

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An experimental bimorph piezoelectric element (PZT) actuator for small pipe robot is developed. The robotcan move in φ 20 mm pipe, and can carry a CCD camera for detecting cracks or fine holes on inner surface of pipe. Thevelocity of the robot can reach 17~22 mm/s for vertical pipe up/down, respectively. Moving principle and its perfor-mance characteristics are presented.

  7. Flow Energy Piezoelectric Bimorph Nozzle Harvester

    Science.gov (United States)

    Sherrit, Stewart; Lee, Hyeong Jae; Kim, Namhyo; Sun, Kai; Corbett, Gary; Walkemeyer, Phillip; Hasenoehrl, Jennifer; Hall, Jeffery L.; Colonius, Tim; Tosi, Luis Phillipe; Arrazola, Alvaro

    2014-01-01

    There is a need for a long-life power generation scheme that could be used downhole in an oil well to produce 1 Watt average power. There are a variety of existing or proposed energy harvesting schemes that could be used in this environment but each of these has its own limitations. The vibrating piezoelectric structure is in principle capable of operating for very long lifetimes (decades) thereby possibly overcoming a principle limitation of existing technology based on rotating turbo-machinery. In order to determine the feasibility of using piezoelectrics to produce suitable flow energy harvesting, we surveyed experimentally a variety of nozzle configurations that could be used to excite a vibrating piezoelectric structure in such a way as to enable conversion of flow energy into useful amounts of electrical power. These included reed structures, spring mass-structures, drag and lift bluff bodies and a variety of nozzles with varying flow profiles. Although not an exhaustive survey we identified a spline nozzle/piezoelectric bimorph system that experimentally produced up to 3.4 mW per bimorph. This paper will discuss these results and present our initial analyses of the device using dimensional analysis and constitutive electromechanical modeling. The analysis suggests that an order-of-magnitude improvement in power generation from the current design is possible.

  8. Polymer-Ceramic MEMS Bimorphs as Thermal Infrared Sensors

    OpenAIRE

    Warren, Clinton Gregory

    2010-01-01

    Thermal infrared detectors based on MEMS bimorph beams have the potential to exceed the performance of current uncooled thermal infrared cameras both in terms of sensitivity and cost. These cameras are part of a rapidly growing industry are used for a vast array of applications such as military and civilian night vision, industrial monitoring, and medical imaging. Many researchers have explored the use of metal-ceramic MEMS bimorphs for this application even though it has long been acknowle...

  9. Development of a Micro-Gripper Using Piezoelectric Bimorphs

    Directory of Open Access Journals (Sweden)

    Nur Azah Hamzaid

    2013-05-01

    Full Text Available Piezoelectric bimorphs have been used as a micro-gripper in many applications, but the system might be complex and the response performance might not have been fully characterized. In this study the dynamic characteristics of bending piezoelectric bimorphs actuators were theoretically and experimentally investigated for micro-gripping applications in terms of deflection along the length, transient response, and frequency response with varying driving voltages and driving signals. In addition, the implementation of a parallel micro-gripper using bending piezoelectric bimorphs was presented. Both fingers were actuated separately to perform mini object handling. The bending piezoelectric bimorphs were fixed as cantilevers and individually driven using a high voltage amplifier and the bimorph deflection was measured using a non contact proximity sensor attached at the tip of one finger. The micro-gripper could perform precise micro-manipulation tasks and could handle objects down to 50 µm in size. This eliminates the need for external actuator extension of the microgripper as the grasping action was achieved directly with the piezoelectric bimorph, thus minimizing the weight and the complexity of the micro-gripper.

  10. Development of a high performance peristaltic micropump

    Science.gov (United States)

    Pham, My; Goo, Nam Seo

    2008-03-01

    In this study, a high performance peristaltic micropump has been developed and investigated. The micropump has three cylinder chambers which are connected through micro-channels for high pumping pressure performance. A circular-shaped mini LIPCA has been designed and manufactured for actuating diaphragm. In this LIPCA, a 0.1mm thickness PZT ceramic is used as an active layer. As a result, the actuator has shown to produce large out of plane deflection and consumed low power. During the design process, a coupled field analysis was conducted to predict the actuating behavior of a diaphragm and pumping performance. MEMS technique was used to fabricate the peristaltic micropump. Pumping performance of the present micropump was investigated both numerically and experimentally. The present peristaltic micropump was shown to have higher performance than the same kind of micropump developed else where.

  11. Surface micromachined electrostatically actuated micro peristaltic pump

    OpenAIRE

    Xie, Jun; Shih, Jason; Lin, Qiao; Yang, Bozhi; Tai, Yu-Chong

    2004-01-01

    An electrostatically actuated micro peristaltic pump is reported. The micro pump is entirely surface micromachined using a multilayer parylene technology. Taking advantage of the multilayer technology, the micro pump design enables the pumped fluid to be isolated from the electric field. Electrostatic actuation of the parylene membrane using both DC and AC voltages was demonstrated and applied to fluid pumping based on a 3-phase peristaltic sequence. A maximum flow rate of 1.7 nL min^–1 and a...

  12. Analytical modelling and free vibration analysis of piezoelectric bimorphs

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yan-guo; CHEN Yun-min; DING Hao-jiang

    2005-01-01

    An efficient and accurate analytical model for piezoelectric bimorph based on the improved first-order shear deformation theory (FSDT) is developed in this work. The model combines the equivalent single-layer approach for mechanical displacements and a layerwise-type modelling of the electric potential. Particular attention is devoted to the boundary conditions on the outside faces and to the interface continuity conditions of the bimorphs for the electromechanical variables. Shear correction factor (k) is introduced to modify both the shear stress and the electric displacement of each layer. And the detailed mathematical derivations are presented. Free vibration problem of simply supported piezoelectric bimorphs with series or parallel arrangement is investigated for the closed circuit condition, and the results for different length-to-thickness ratios are compared with those obtained from the exact 2D solution. Excellent agreements between the present model prediction with k=8/9 and the exact solutions are observed for the resonant frequencies.

  13. Theoretical analysis and simulation of thermoelastic deformation of bimorph microbeams

    Institute of Scientific and Technical Information of China (English)

    SHANG; YuanFang; YE; XiongYing; FENG; JinYang

    2013-01-01

    In this paper, a purely mechanical model for the thermoelastic behavior of a bimorph microbeam is presented. The thermoelastic coupling problem of the microbeam is converted to a mechanical problem by simply replacing the thermal stress in the beam with a bulk force and a surface force. Thermoelastic deformation of the bimorph microbeams with constraints frequently used in micro-electro-mechanical systems (MEMS) devices has been derived based on this model and is characterized by FEA simulation. Coincidence of the results from theory and simulation demonstrates the validity of the model. The analysis shows that a bimorph microbeam with a soft constraint and a uniform temperature field has a larger thermoelastic deformation than that with a hard constraint and a linear temperature field. In addition to the adoption of materials with large CTE mismatch,thickness ratio and length ratio of the two layers need to be optimized to get a large thermoelastic deformation.

  14. Bimorph based Active Joints for Nanometre scale Actuation

    NARCIS (Netherlands)

    Chakkalakkal Abdulla, S.M.; Krijnen, G.J.M.

    2007-01-01

    In this work the modelling of a micro bimorph cantilever which is composed of a Silicon Nitride cantilever beam coated on top with a thin Chromium layer is described. The structure functions as a vertical electrostatic actuator for nanometre displacements with stress induced upward curvature in the

  15. Piezoelectric peristaltic micropump with a single actuator

    Science.gov (United States)

    Pečar, Borut; Križaj, Dejan; Vrtačnik, Danilo; Resnik, Drago; Dolžan, Tine; Možek, Matej

    2014-10-01

    A high performance piezoelectric PDMS peristaltic micropump with a single actuator is presented that enables driving with less expensive and simpler single-phase controllers while maintaining all the superior properties of conventional peristaltic micropumps, such as robustness, simplicity and purity due to the absence of valves. A simple structural design is based on a centrally placed inlet port which leads directly into the center of the pumping chamber. During excitation the loosely attached glass membrane and elastomer (PDMS) deform in a controlled manner, which enables compression and expansion of the central inlet port and the outlet fluidic channel with a phase lag that is typical for operation of peristaltic pumps. For proper micropump operation, the volume of the circular pumping chamber area should be much larger than the volume around the secondary deformation extremum that appears in the area of the outlet fluidic channel. To experimentally validate the principle of operation and evaluate the repeatability of the fabrication process, four monoactuator peristaltic (MAP) micropump prototypes were fabricated and characterized. Fabricated prototypes featured high water / air flowrate performance (up to 0.24 ml min-1/up to 0.84 ml min-1), back-pressure performance (up to 360 mbar/up to 80 mbar) and suction pressure performance (down to -165 mbar/down to -140 mbar). Furthermore, bubble tolerance and self-priming capability have been proved, together with valve regime of operation that enables sealing of the fluidic path when appropriate dc voltage is applied.

  16. Linear peristaltic pump based on electromagnetic actuators

    Directory of Open Access Journals (Sweden)

    Maddoui Lotfi

    2014-01-01

    Full Text Available In this paper a study and design of a linear peristaltic pump are presented. A set of electromagnetic (solenoid actuators is used as the active tools to drag the liquid by crushing an elastic tube. The pump consists of six serially-connected electromagnetic actuators controlled via an electronic board. This may be considered as a simulated peristalsis action of intestines. The dynamic performances of the pump are investigated analytically and experimentally.

  17. A parallel leaf spring structure driven by piezoelectric bimorph actuators

    Science.gov (United States)

    Seki, Hiroya; Gohda, Tomio; Shimokohbe, Akira

    A parallel leaf spring structure driven by piezoelectric bimorph actuator is modelled using a Rayleigh-Ritz formulation and model truncation is done for feedback controller design. Using a strain gauge sensor, a precise positioning of the end point mass is realized. The position of the strain gauge sensor is found to be an important factor in achieving a stable response with an estimator based feedback control system. Also excitation of higher structural modes, which becomes an obstacle to a wide servo bandwidth actuator, is discussed. Using multi electrodes arranged on the bimorph actuator and appropriately tuning the voltage ratio applied to them, pole-zero cancellation of the higher modes is experimentally demonstrated.

  18. An in-pipe micro robot actuated by piezoelectric bimorphs

    Institute of Scientific and Technical Information of China (English)

    LIU PinKuan; WEN ZhiJie; SUN LiNing

    2009-01-01

    A novel in-pipe micro robot providing stable and accurate locomotion inside a tubular structure with diameters ranging from 16 mm to 18 mm is presented in this paper. Driven by impulsive voltages, deflections of the piezoelectric bimorphs are generated and then converted into translational locomotion by the principle of the Impact Drive Mechanism (IDM). Theoretical analysis of the proposed system is performed based on a simplified mechanical model. Then dynamic simulations of the dynamic behavior are performed. Finally, an experiment is conducted to investigate the moving ability of this device. The results demonstrate that a maximum translational velocity of 3.5 mm/s can be obtained under an impulsive driving voltage with peak value at 50 V and frequency of 1100 Hz. Both theoretical analysis and experimental trials prove that the principle of IDM actuated by piezoelectric bimorphs is feasible and robust for achieving accurate locomotion of the micro robot in pipes with diameters of less than 20 mm.

  19. Electromechanical properties of nanotube PVA composite actuator bimorphs

    Science.gov (United States)

    Bartholome, Christèle; Derré, Alain; Roubeau, Olivier; Zakri, Cécile; Poulin, Philippe

    2008-08-01

    Oxidized multiwalled carbon nanotube (oxidized-MWNT)/polyvinyl alcohol (PVA) composite sheets have been prepared for electromechanical actuator applications. MWNT have been oxidized by nitric acid treatments. They were then dispersed in water and mixed with various amounts of PVA of high molecular weight (198 000 g mol-1). The composite sheets were then obtained through a membrane filtration process. The composition of the systems has been optimized to combine suitable mechanical and electrical properties. Thermogravimetric analysis, mechanical tensile tests and conductivity measurements show that the best compromise of mechanical and electrical properties was obtained for a PVA weight fraction of about 30 wt%. In addition, one face of the sheets was coated with gold to increase the conductivity of the sheets and promote uniform actuation. Pseudo-bimorph devices have been realized by subsequently coating the composite sheets with an inert layer of PVA. The devices have been tested electromechanically in a liquid electrolyte (tetrabutylammonium/tetrafluoroborate (TBA/TFB) in acetonitrile) at constant frequency and different applied voltages, from 2 to 10 V. Measurements of the bimorph deflections were used to determine the stress generated by the nanotube-PVA sheets. The results show that the stress generated increases with increasing amplitude of the applied voltage and can reach 1.8 MPa. This value compares well with and even exceeds the stress generated by recently obtained bimorphs made of gold nanoparticles.

  20. Electromechanical properties of nanotube-PVA composite actuator bimorphs

    Energy Technology Data Exchange (ETDEWEB)

    Bartholome, Christele; Derre, Alain; Roubeau, Olivier; Zakri, Cecile; Poulin, Philippe [Centre de Recherche Paul Pascal-CNRS, Avenue Schweitzer 33600 Pessac (France)], E-mail: bartholo@crpp-bordeaux.cnrs.fr, E-mail: derre@crpp-bordeaux.cnrs.fr, E-mail: roubeau@crpp-bordeaux.cnrs.fr, E-mail: zakri@crpp-bordeaux.cnrs.fr, E-mail: poulin@crpp-bordeaux.cnrs.fr

    2008-08-13

    Oxidized multiwalled carbon nanotube (oxidized-MWNT)/polyvinyl alcohol (PVA) composite sheets have been prepared for electromechanical actuator applications. MWNT have been oxidized by nitric acid treatments. They were then dispersed in water and mixed with various amounts of PVA of high molecular weight (198 000 g mol{sup -1}). The composite sheets were then obtained through a membrane filtration process. The composition of the systems has been optimized to combine suitable mechanical and electrical properties. Thermogravimetric analysis, mechanical tensile tests and conductivity measurements show that the best compromise of mechanical and electrical properties was obtained for a PVA weight fraction of about 30 wt%. In addition, one face of the sheets was coated with gold to increase the conductivity of the sheets and promote uniform actuation. Pseudo-bimorph devices have been realized by subsequently coating the composite sheets with an inert layer of PVA. The devices have been tested electromechanically in a liquid electrolyte (tetrabutylammonium/tetrafluoroborate (TBA/TFB) in acetonitrile) at constant frequency and different applied voltages, from 2 to 10 V. Measurements of the bimorph deflections were used to determine the stress generated by the nanotube-PVA sheets. The results show that the stress generated increases with increasing amplitude of the applied voltage and can reach 1.8 MPa. This value compares well with and even exceeds the stress generated by recently obtained bimorphs made of gold nanoparticles.

  1. Peristaltic pumps work in nano scales

    OpenAIRE

    Farahpour, Farnoush; Ejtehadi, Mohammad Reza

    2013-01-01

    A design for a pump is suggested which is based on well-known peristaltic pumps. In order to simply describe the operation of the proposed pump, an innovative interpretation of low Reynolds number swimmers is presented and thereafter a similar theoretical model would be suggested to quantify the behavior of the pumps. A coarse-grained molecular dynamic simulation is used to examine the theoretical predictions and measure the efficiency of the pump in nano scales. It is shown that this pump wi...

  2. Peristaltic Transport through Eccentric Cylinders: Mathematical Model

    Directory of Open Access Journals (Sweden)

    Kh. S. Mekheimer

    2013-01-01

    Full Text Available This paper discusses the effect of peristaltic transport on the fluid flow in the gap between two eccentric tubes (eccentric-annulus flows. The inner tube is uniform, rigid, while the outer tube has a sinusoidal wave traveling down its wall. The flow analysis has been developed for low Reynolds number and long wave length approximation. The velocity and the pressure gradient have been obtained in terms of the dimensionless flow rate Q¯, time t, azimuthal coordinate θ and eccentricity parameter ϵ (the parameter that controls of the eccentricity of the inner tube position. The results show that there is a significant deference between eccentric and concentric annulus flows.

  3. Competition between the Thermal Gradient and the Bimorph Effect in Locally Heated MEMS Actuators

    DEFF Research Database (Denmark)

    Jeppesen, Claus; Mølhave, Kristian; Kristensen, Anders

    2009-01-01

    modeling. As a result, bidirectional bending has been experimentally observed and interpreted as the competition between bimorph and thermal gradient effects. The competition has illustrated the importance of including the thermal gradient effect in the behavior analysis of bimorph driven MEMS/NEMS devices....

  4. A linear peristaltic MRF/foam actuator

    Science.gov (United States)

    Larsen, J. J.; Jenkins, C. H.; Korde, U. A.

    2007-04-01

    , peristaltic pumps in industry are common for a variety of material handling applications, particularly involving the movement of sterile fluids (for example, blood). The peristaltic pump is usually circular in configuration, relying on external rollers to move fluid within a tube. Some linear configuration pumps have been proposed and developed, however they are complicated than their circular counterparts. In the remaining part of the present work, we discuss the development of a linear peristaltic actuator based upon the deformation of MRF/foam. The actuator consists of an open-cell polymer foam substrate infused with MRF. To one side of the foam substrate resides a translating magnet, such that a magnetic field can be propagated down its length. The linear peristaltic action is generated as the transversely propagating field shapes the MRF/foam substrate in a corresponding way. Experimental results are discussed, an outline of on-going theoretical modeling is presented, and conclusions are provided.

  5. Microbionic and peristaltic robots in a pipe

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A microbionic and peristaltic robot that simulates the motion of an earthworm to move within a micropipe is proposed. The robot consists of three flexible units. Each unit is composed of two plates connected with three shape memory alloys (SMA) 120°apart, the rubber gasbag around the SMA wires inflated with air inside. Each unit corresponds to a segment of an earthworm, and the SMA and rubber gasbag have the same functions as the cricoid and longitudinal muscles of the earthworm. A control system is designed to fulfill the control of the three flexible units motions, such as stretching, shrinking and bending, so the microrobot can walk forward and backward, and choose the direction.

  6. Swimming and peristaltic pumping between two plane parallel walls

    International Nuclear Information System (INIS)

    Swimming at low Reynolds number in a fluid confined between two plane walls is studied for an infinite plane sheet located midway between the walls and distorted with a transverse propagating wave. It is shown that the flow pattern is closely related to that for peristaltic pumping. The hydrodynamic interaction between two flexible sheets swimming parallel in infinite space is related to the problem of peristaltic pumping in a planar channel with two wavy walls.

  7. Design of a bimorph piezoelectric energy harvester for railway monitoring

    International Nuclear Information System (INIS)

    Wireless sensor network is one of prospective methods for railway monitoring due to the long term operation and low maintenance performances. How to supply power to the wireless sensor nodes has drawn much attention recently. In railway monitoring, the idea of converting ambient vibration energy from vibration of railway track induced by passing trains to electric energy has made it a potential way for powering the wireless sensor nodes. In this paper, a bimorph cantilever piezoelectric energy harvester was designed based on a single degree of freedom model. Experimental test was also performed to validate the design. The first natural frequency of the bimorph piezoelectric energy harvester was decreased from 117.1 Hz to 65.2 Hz by adding 4 gram tip mass to the free end of the 8.6 gram energy harvester. In addition, the power generation of the piezoelectric energy harvester with 4 gram tip mass at resonant frequency was increased from 0.14 mW to 0.74 mW from 2.06 m/s2 base excitation compared to stand alone piezoelectric energy harvester without tip mass

  8. Design of a bimorph piezoelectric energy harvester for railway monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jingcheng; Jang, Shinae; Tang, Jiong [Univ. of Connecticut, Connecticut (United States)

    2012-12-15

    Wireless sensor network is one of prospective methods for railway monitoring due to the long term operation and low maintenance performances. How to supply power to the wireless sensor nodes has drawn much attention recently. In railway monitoring, the idea of converting ambient vibration energy from vibration of railway track induced by passing trains to electric energy has made it a potential way for powering the wireless sensor nodes. In this paper, a bimorph cantilever piezoelectric energy harvester was designed based on a single degree of freedom model. Experimental test was also performed to validate the design. The first natural frequency of the bimorph piezoelectric energy harvester was decreased from 117.1 Hz to 65.2 Hz by adding 4 gram tip mass to the free end of the 8.6 gram energy harvester. In addition, the power generation of the piezoelectric energy harvester with 4 gram tip mass at resonant frequency was increased from 0.14 mW to 0.74 mW from 2.06 m/s{sup 2} base excitation compared to stand alone piezoelectric energy harvester without tip mass.

  9. Enhanced Magnetoelectric Coupling in Layered Structure of Piezoelectric Bimorph and Metallic Alloy

    Science.gov (United States)

    Petrov, V. M.; Bichurin, M. I.; Lavrentyeva, K. V.; Leontiev, V. S.

    2016-08-01

    We have investigated the enhanced magnetoelectric (ME) coupling in a layered structure of piezoelectric bimorph and magnetostrictive metallic alloy. The observed ME coefficient in the piezoelectric bimorph-based structure was found to be two times higher than in the traditional piezoelectric/magnetostrictive bilayer. The observed enhancement in ME coupling strength is related to equal signs of induced voltage in both lead zirconate titanate layers with opposite poling directions due to the flexural deformations. The piezoelectric bimorph-based structure has promising potential for sensor and technological applications.

  10. Development and characterization of thermopneumatic peristaltic micropumps

    International Nuclear Information System (INIS)

    In this paper, the development and characterization of thermopneumatic peristaltic micropumps are presented. Micropumps with three different designs are fabricated using soft lithography techniques. The equivalent circuit models of a thermopneumatic actuation cell are formulated. The analytical solutions for predicting the device transient behavior are also derived. The dynamical responses of the diaphragms are measured using an interferometer, and are in good agreement with the modeled results. Tiny drive circuits, which require only 5 V, are implemented for driving the pumps. The dimension of an integrated 3-chamber micropump system, which consists of a pump and a drive circuit, is 16 mm × 18 mm × 5.5 mm. The optimal operating conditions, such as actuation sequences, operating frequencies and duty ratios, are obtained. The maximum flow rate occurs at a driving frequency of 1.5 Hz with a duty ratio of 40% using a three-phase actuation sequence. A simplified pseudo thermo-fluid-structure-interaction (pT-FSI) model is also proposed to estimate the pumping characteristic. The model gives reasonable results under low operation frequency. Under zero backpressure, the maximum flow rates for the 3, 5 and 7-chamber devices are very close, whereas the devices with larger numbers of pumping chambers exhibit better pumping performance under higher backpressure

  11. Development and characterization of thermopneumatic peristaltic micropumps

    Science.gov (United States)

    Yang, Yao-Joe; Liao, Hsin-Hung

    2009-02-01

    In this paper, the development and characterization of thermopneumatic peristaltic micropumps are presented. Micropumps with three different designs are fabricated using soft lithography techniques. The equivalent circuit models of a thermopneumatic actuation cell are formulated. The analytical solutions for predicting the device transient behavior are also derived. The dynamical responses of the diaphragms are measured using an interferometer, and are in good agreement with the modeled results. Tiny drive circuits, which require only 5 V, are implemented for driving the pumps. The dimension of an integrated 3-chamber micropump system, which consists of a pump and a drive circuit, is 16 mm × 18 mm × 5.5 mm. The optimal operating conditions, such as actuation sequences, operating frequencies and duty ratios, are obtained. The maximum flow rate occurs at a driving frequency of 1.5 Hz with a duty ratio of 40% using a three-phase actuation sequence. A simplified pseudo thermo-fluid-structure-interaction (pT-FSI) model is also proposed to estimate the pumping characteristic. The model gives reasonable results under low operation frequency. Under zero backpressure, the maximum flow rates for the 3, 5 and 7-chamber devices are very close, whereas the devices with larger numbers of pumping chambers exhibit better pumping performance under higher backpressure.

  12. Optofluidic modulator based on peristaltic nematogen microflows

    Science.gov (United States)

    Cuennet, J. G.; Vasdekis, A. E.; de Sio, L.; Psaltis, D.

    2011-04-01

    Nematogens rotate by the application of external fields, thereby enabling optical modulation. This principle has had a profound impact on our daily lives through the plethora of liquid-crystal displays in use around us. However, the wider use of nematic liquid crystals, particularly in microdisplays and information processing, has been hampered by their slow response times. In nematogens, rotational and translational molecular motions are coupled, so flow is inevitably linked with optical modulation. This linkage motivated us to fuse microfluidics with anisotropic liquids and introduce an optofluidic modulator that exhibits a submillisecond (250 µs) symmetric response and can operate at frequencies up to 1 kHz. The modulator is based on peristaltic nematogen microflows realized in polydimethylsiloxane microfluidics. The latter simultaneously permits peristalsis by means of elastomeric deformation, nematogen alignment and rapid prototyping through cast-moulding. Together with large-scale, vertical integration and piezoelectric nanotechnologies, this optofluidic paradigm can enable high-density and three-dimensional architectures of fast modulators.

  13. A vacuum-driven peristaltic micropump with valved actuation chambers

    International Nuclear Information System (INIS)

    This paper presents a simple peristaltic micropump design incorporated with valved actuation chambers and propelled by a pulsed vacuum source. The vacuum-driven peristaltic micropump offers high pumping rates, low backflow, appreciable tolerance to air bubbles, and minimal destruction to fluid contents. The pumping device, fabricated by laser micromachining and plasma bonding of three polydimethylsiloxane (PDMS) layers, includes a pneumatic network, actuation membranes, and microfluidic channels. As the key to peristaltic motion, the sequential deflection of the elastic membranes is achieved by periodic pressure waveforms (negative) traveling through the pneumatic network, provided by a vacuum source regulated by an electromagnetic valve. This configuration eliminates the complicated control logic typically required in peristaltic motion. Importantly, the valved actuation chambers substantially reduce backflow and improve the pumping rates. In addition, the pneumatic network with negative pressure provides a means to effectively remove air bubbles present in the microflow through the gas-permeable PDMS membrane, which can be highly desired in handling complex fluidic samples. Experimental characterization of the micropump performance has been conducted by controlling the resistance of the pneumatic network, the number of normally closed valves, the vacuum pressure, and the frequency of pressure pulses. A maximal flow rate of 600 µL min−1 has been optimized at the pulsed vacuum frequency of 30 Hz with a vacuum pressure of 50 kPa, which is comparable to that of compressed air-actuated peristaltic micropumps

  14. Bimorph actuators in thick SiO2 for photonic alignment

    Science.gov (United States)

    Wu, Kai; Peters, Tjitte-Jelte; Tichem, Marcel; Postma, Ferry; Prak, Albert; Wörhoff, Kerstin; Leinse, Arne

    2016-03-01

    This paper proposes and tests a design of electro-thermal bimorph actuators for alignment of flexible photonic waveguides fabricated in 16 µm thick SiO2. The actuators are for use in a novel alignment concept for multi-port photonic integrated circuits (PICs), in which the fine alignment is taken care of by positioning of suspended, mechanically flexible waveguide beams on one or more of the PICs. The design parameters of the bimorph actuator allow to tune both the initial relative position of the waveguide end-facets, and the motion range of the actuators. Bimorph actuators have been fabricated and characterized. The maximum out-of-plane deflection of the bimorph actuator (with 720 μm-long poly-Si) can reach 18:5 μm with 126:42mW, sufficient for the proposed application.

  15. Analysis of a piezoelectric bimorph plate with a central-attached mass as an energy harvester.

    Science.gov (United States)

    Jiang, Shunong; Hu, Yuantai

    2007-07-01

    This article analyzes the performance of a piezoelectric energy harvester in the flexural mode for scavenging ambient vibration energy. The energy harvester consists of a piezoelectric bimorph plate with a central-attached mass. The linear piezoelectricity theory is applied to evaluate the performance dependence upon the physical and geometrical parameters of the model bimorph plate. The analytical solution for the flexural motion of the piezoelectric bimorph plate energy harvester shows that the output power density increases initially, reaches a maximum, then decreases monotonically with the increasing load impedance, which is normalized by a parameter that is a simple combination of the physical and geometrical parameters of the scavenging structure, the bimorph plate, and the frequency of the ambient vibration, underscoring the importance for the load circuit to have the impedance desirable by the scavenging structure. The numerical results illustrate the considerably enhanced performances by adjusting the physical and geometrical parameters of the scavenging structure. PMID:17718336

  16. Analytical Modelling of a Plucked Piezoelectric Bimorph for Energy Harvesting

    CERN Document Server

    Pozzi, Michele

    2012-01-01

    Energy harvesting (EH) is a multidisciplinary research area, involving physics, materials science and engineering, with the objective of providing renewable sources of sufficient power to operate targeted low-power applications. Piezoelectric transducers are often used for vibrational, inertial and direct movement EH. One problem is that, due to the stiffness of the most common material (PZT) and typically useful sizes, intrinsic resonant frequencies are normally high, whereas the available power is often concentrated at low frequencies. The aim of the plucking technique of frequency up-conversion, also known as "pizzicato" excitation, is to bridge this frequency gap. In this paper, the technique is modelled analytically. The analytical model is developed starting from the Euler-Bernoulli beam equations modified for piezoelectric coupling. A system of differential equations and associated initial conditions are derived which describe the free vibration of a piezoelectric bimorph in the last part of the plucki...

  17. Postprandial transduodenal bolus transport is regulated by complex peristaltic sequence

    Institute of Scientific and Technical Information of China (English)

    Huan Nam Nguyen; Ron Winograd; Gerson Ricardo Souza Domingues; Frank Lammert

    2006-01-01

    AIM: To study the relationship between the patterns of postprandial peristalsis and transduodenal bolus transport in healthy subjects.METHODS: Synchronous recording of chyme transport and peristaltic activity was performed during the fasting state and after administration of a test meal using a special catheter device with cascade configuration of impedance electrodes and solid-state pressure transducers. The catheter was placed into the duodenum,where the first channel was located in the first part of the duodenum and the last channel at the duodenojejunal junction. After identification of previously defined chyme transport patterns the associated peristaltic patterns were analyzed.RESULTS: The interdigestive phase 3 complex was reliably recorded with both techniques. Of 497 analyzed impedance bolus transport events, 110 (22%) were short-spanned propulsive, 307 (62%) long-spanned propulsive, 70 (14%)complex propulsive, and 10 (2%) retrograde transport.Short-spanned chyme transports were predominantly associated with stationary or propagated contractions propagated over short distance. Long-spanned and complex chyme transports were predominantly associated with propulsive peristaltic patterns, which were frequently complex and comprised multiple contractions. Propagated double wave contraction, propagated contraction with a clustered contraction, and propagated cluster of contractions have been identified to be an integralted part of a peristaltic sequence in human duodenum.CONCLUSION: Combined impedancometry andmanometry improves the analysis of the peristaltic patterns that are associated with postprandial transduodenal chyme transport. Postprandial transduodenal bolus transport is regulated by propulsive peristaltic patterns, which are frequently complex but well organized. This finding should be taken into consideration in the analysis of intestinal motility studies.

  18. Heat Transfer Analysis for Peristaltic Mechanism in Variable Viscosity Fluid

    Institute of Scientific and Technical Information of China (English)

    T.Hayat; F.M.Abbasi; Awatif A.Hendi

    2011-01-01

    An analysis is carried out for a peristaltic flow of a third-order fluid with heat transfer and variable viscosity when no-slip condition does not hold. Perturbation solution is discussed and a comparative study between the cases of constant and variable viscosities is presented and analyzed.%@@ An analysis is carried out for a peristaltic flow of a third-order fluid with heat transfer and variable viscosity when no-slip condition does not hold.Perturbation solution is discussed and a comparative stuity between the cases of constant and variable viscosities is presented and analyzed.

  19. Characterization of a next-generation piezo bimorph X-ray mirror for synchrotron beamlines

    International Nuclear Information System (INIS)

    A next-generation bimorph mirror with piezos bonded to the side faces of a monolithic substrate was created. When replacing a first-generation bimorph mirror suffering from the junction effect, the new type of mirror significantly improved the size and shape of the reflected synchrotron X-ray beam. No evidence of the junction effect was observed even after eight months of continuous beamline usage. Piezo bimorph mirrors are versatile active optics used on many synchrotron beamlines. However, many bimorphs suffer from the ‘junction effect’: a periodic deformation of the optical surface which causes major aberrations to the reflected X-ray beam. This effect is linked to the construction of such mirrors, where piezo ceramics are glued directly below the thin optical substrate. In order to address this problem, a next-generation bimorph with piezos bonded to the side faces of a monolithic substrate was developed at Thales-SESO and optimized at Diamond Light Source. Using metrology feedback from the Diamond-NOM, the optical slope error was reduced to ∼0.5 µrad r.m.s. for a range of ellipses. To maximize usability, a novel holder was built to accommodate the substrate in any orientation. When replacing a first-generation bimorph on a synchrotron beamline, the new mirror significantly improved the size and shape of the reflected X-ray beam. Most importantly, there was no evidence of the junction effect even after eight months of continuous beamline usage. It is hoped that this new design will reinvigorate the use of active bimorph optics at synchrotron and free-electron laser facilities to manipulate and correct X-ray wavefronts

  20. Peristaltic pump-based low range pressure sensor calibration system

    Science.gov (United States)

    Vinayakumar, K. B.; Naveen Kumar, G.; Nayak, M. M.; Dinesh, N. S.; Rajanna, K.

    2015-11-01

    Peristaltic pumps were normally used to pump liquids in several chemical and biological applications. In the present study, a peristaltic pump was used to pressurize the chamber (positive as well negative pressures) using atmospheric air. In the present paper, we discuss the development and performance study of an automatic pressurization system to calibrate low range (millibar) pressure sensors. The system includes a peristaltic pump, calibrated pressure sensor (master sensor), pressure chamber, and the control electronics. An in-house developed peristaltic pump was used to pressurize the chamber. A closed loop control system has been developed to detect and adjust the pressure leaks in the chamber. The complete system has been integrated into a portable product. The system performance has been studied for a step response and steady state errors. The system is portable, free from oil contaminants, and consumes less power compared to existing pressure calibration systems. The veracity of the system was verified by calibrating an unknown diaphragm based pressure sensor and the results obtained were satisfactory.

  1. Peristaltic pump-based low range pressure sensor calibration system

    International Nuclear Information System (INIS)

    Peristaltic pumps were normally used to pump liquids in several chemical and biological applications. In the present study, a peristaltic pump was used to pressurize the chamber (positive as well negative pressures) using atmospheric air. In the present paper, we discuss the development and performance study of an automatic pressurization system to calibrate low range (millibar) pressure sensors. The system includes a peristaltic pump, calibrated pressure sensor (master sensor), pressure chamber, and the control electronics. An in-house developed peristaltic pump was used to pressurize the chamber. A closed loop control system has been developed to detect and adjust the pressure leaks in the chamber. The complete system has been integrated into a portable product. The system performance has been studied for a step response and steady state errors. The system is portable, free from oil contaminants, and consumes less power compared to existing pressure calibration systems. The veracity of the system was verified by calibrating an unknown diaphragm based pressure sensor and the results obtained were satisfactory

  2. Electroosmosis-modulated peristaltic transport in microfluidic channels

    Science.gov (United States)

    Bandopadhyay, Aditya; Tripathi, Dharmendra; Chakraborty, Suman

    2016-05-01

    We analyze the peristaltic motion of aqueous electrolytes altered by means of applied electric fields. Handling electrolytes in typical peristaltic channel material such as polyvinyl chloride and Teflon leads to the generation of a net surface charge on the channel walls, which attracts counter-ions and repels co-ions from the aqueous solution, thus leading to the formation of an electrical double layer—a region of net charges near the wall. We analyze the spatial distribution of pressure and wall shear stress for a continuous wave train and single pulse peristaltic wave in the presence of an electrical (electroosmotic) body force, which acts on the net charges in the electrical double layer. We then analyze the effect of the electroosmotic body force on the particle reflux as elucidated through the net displacement of neutrally buoyant particles in the flow as the peristaltic waves progress. The impact of combined electroosmosis and peristalsis on trapping of a fluid volume (e.g., bolus) inside the travelling wave is also discussed. The present analysis goes beyond the traditional analysis, which neglects the possibility of coupling the net pumping of fluids due to peristalsis and allows us to derive general expressions for the pressure drop and flow rate in order to set up a general framework for incorporating flow control and actuation by simultaneous peristalsis and application of electric fields to aqueous solutions. It is envisaged that the results presented here may act as a model for the design of lab-on-a-chip devices.

  3. Peristaltic pump-based low range pressure sensor calibration system.

    Science.gov (United States)

    Vinayakumar, K B; Naveen Kumar, G; Nayak, M M; Dinesh, N S; Rajanna, K

    2015-11-01

    Peristaltic pumps were normally used to pump liquids in several chemical and biological applications. In the present study, a peristaltic pump was used to pressurize the chamber (positive as well negative pressures) using atmospheric air. In the present paper, we discuss the development and performance study of an automatic pressurization system to calibrate low range (millibar) pressure sensors. The system includes a peristaltic pump, calibrated pressure sensor (master sensor), pressure chamber, and the control electronics. An in-house developed peristaltic pump was used to pressurize the chamber. A closed loop control system has been developed to detect and adjust the pressure leaks in the chamber. The complete system has been integrated into a portable product. The system performance has been studied for a step response and steady state errors. The system is portable, free from oil contaminants, and consumes less power compared to existing pressure calibration systems. The veracity of the system was verified by calibrating an unknown diaphragm based pressure sensor and the results obtained were satisfactory. PMID:26628178

  4. Peristaltic pump-based low range pressure sensor calibration system

    Energy Technology Data Exchange (ETDEWEB)

    Vinayakumar, K. B. [Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 5600012 (India); Department of Electronic Systems Engineering, Indian Institute of Science, Bangalore 5600012 (India); Naveen Kumar, G.; Rajanna, K., E-mail: kraj@isu.iisc.ernet.in, E-mail: krajanna2011@gmail.com [Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 5600012 (India); Nayak, M. M. [Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 5600012 (India); Dinesh, N. S. [Department of Electronic Systems Engineering, Indian Institute of Science, Bangalore 5600012 (India)

    2015-11-15

    Peristaltic pumps were normally used to pump liquids in several chemical and biological applications. In the present study, a peristaltic pump was used to pressurize the chamber (positive as well negative pressures) using atmospheric air. In the present paper, we discuss the development and performance study of an automatic pressurization system to calibrate low range (millibar) pressure sensors. The system includes a peristaltic pump, calibrated pressure sensor (master sensor), pressure chamber, and the control electronics. An in-house developed peristaltic pump was used to pressurize the chamber. A closed loop control system has been developed to detect and adjust the pressure leaks in the chamber. The complete system has been integrated into a portable product. The system performance has been studied for a step response and steady state errors. The system is portable, free from oil contaminants, and consumes less power compared to existing pressure calibration systems. The veracity of the system was verified by calibrating an unknown diaphragm based pressure sensor and the results obtained were satisfactory.

  5. Long Wavelength Peristaltic Transport of Non-Newton Fluids

    OpenAIRE

    Devanathan, R; Parvathamma, S.

    1980-01-01

    Solutions are obtained for the stream function and the pressure field for the flow of non-Newtonian fluids in a tube by long peristaltic waves of arbitrary shape. The axial velocity profiles and stress distributions on the wall are discussed for particular waves of some practical interest. The effect of non- Newtonian character of the fluid is examined.

  6. Peristaltic pump-based low range pressure sensor calibration system.

    Science.gov (United States)

    Vinayakumar, K B; Naveen Kumar, G; Nayak, M M; Dinesh, N S; Rajanna, K

    2015-11-01

    Peristaltic pumps were normally used to pump liquids in several chemical and biological applications. In the present study, a peristaltic pump was used to pressurize the chamber (positive as well negative pressures) using atmospheric air. In the present paper, we discuss the development and performance study of an automatic pressurization system to calibrate low range (millibar) pressure sensors. The system includes a peristaltic pump, calibrated pressure sensor (master sensor), pressure chamber, and the control electronics. An in-house developed peristaltic pump was used to pressurize the chamber. A closed loop control system has been developed to detect and adjust the pressure leaks in the chamber. The complete system has been integrated into a portable product. The system performance has been studied for a step response and steady state errors. The system is portable, free from oil contaminants, and consumes less power compared to existing pressure calibration systems. The veracity of the system was verified by calibrating an unknown diaphragm based pressure sensor and the results obtained were satisfactory.

  7. A Numerical Investigation of Peristaltic Waves in Circular Tubes

    Science.gov (United States)

    Xiao, Q.; Damodaran, M.

    Peristaltic pumping is a process of fluid transport arising from the progressive waves, which travel along the walls of a flexible channel. It is a primary physiological transport mechanism that is inherent in many tubular organs of the human body such as the ureter, the gastro-intestinal tract, the urethra, and so on. Many studies exist in literature with the aim of understanding the characteristics of peristaltic flow under the assumption of low Reynolds number and infinitely long wavelength in a two-dimensional channel. However, peristaltic pumping is also the mechanism used in other industrial applications such as the blood pump for which the Reynolds number has a moderately high value. As studies concerning moderate to high Reynolds number flow in the circular tube are rare in literature, in the present study, the peristaltic flow of an incompressible fluid is numerically simulated using the finite volume method for solving the incompressible Navier-Stokes equations in primitive variable formulation by means of an infinite train of sinusoidal waves traveling along the wall of an axi-symmetric tube. The computational model presented in this work covers a wider range of Reynolds number (0.01-100), wave amplitude (0-0.8), and wavelength (0.01-0.4) than the those attempted in previous studies reported in literature and some new results pertaining to the distribution of velocity, pressure, wall shear stress for different peristaltic flow conditions characterizing flow at moderately higher Reynolds number have been obtained. The effect of the wave amplitude, wavelength, and Reynolds number on the "flow trapping" mechanism induced by peristalsis has also been investigated here for higher ranges of values of the parameters characterizing peristalsis.

  8. Resonant frequency of a polyvinylidene flouride piezoelectric bimorph: the effect of surrounding fluid

    Science.gov (United States)

    Abedian, Behrouz; Cundari, Michael

    1993-07-01

    This work presents experimental and theoretical results on the dynamic behavior of piezoelectric cantilever bimorph in the presence of surrounding air. The bimorph is composed of a pair of piezoelectric sheets bonded by a uniform elastic layer of adhesive in the center. The transverse motion of the bimorph is generated by a sequential application of two opposing electric fields on the piezoelectric sheets. Theoretically, the tip deflection and the natural frequency of the bimorph are obtained making use of an energy balance technique. The fluid in modeled as inviscid and incompressible whose motion induces locally additional mass in the transverse direction. An expression for the kinetic energy of the system is derived based on this additional mass from which the natural frequency of the combined system is obtained. Tests were performed on the piezoelectric bimorphs with similar geometries and varying adhesive thickness in a vacuum chamber. The air pressure in the chamber was varied from 10 kPa to one atmosphere. Good agreements between the theoretical predictions and the observed values were obtained. This study could have applications in the use of piezoelectric materials for fluid property measurements.

  9. Piezoelectric bimorphs' characteristics as in-socket sensors for transfemoral amputees.

    Science.gov (United States)

    El-Sayed, Amr M; Hamzaid, Nur Azah; Abu Osman, Noor Azuan

    2014-12-10

    Alternative sensory systems for the development of prosthetic knees are being increasingly highlighted nowadays, due to the rapid advancements in the field of lower limb prosthetics. This study presents the use of piezoelectric bimorphs as in-socket sensors for transfemoral amputees. An Instron machine was used in the calibration procedure and the corresponding output data were further analyzed to determine the static and dynamic characteristics of the piezoelectric bimorph. The piezoelectric bimorph showed appropriate static operating range, repeatability, hysteresis, and frequency response for application in lower prosthesis, with a force range of 0-100 N. To further validate this finding, an experiment was conducted with a single transfemoral amputee subject to measure the stump/socket pressure using the piezoelectric bimorph embedded inside the socket. The results showed that a maximum interface pressure of about 27 kPa occurred at the anterior proximal site compared to the anterior distal and posterior sites, consistent with values published in other studies. This paper highlighted the capacity of piezoelectric bimorphs to perform as in-socket sensors for transfemoral amputees. However, further experiments are recommended to be conducted with different amputees with different socket types.

  10. Characterization of a next-generation piezo bimorph X-ray mirror for synchrotron beamlines.

    Science.gov (United States)

    Alcock, Simon G; Nistea, Ioana; Sutter, John P; Sawhney, Kawal; Fermé, Jean Jacques; Thellièr, Christophe; Peverini, Luca

    2015-01-01

    Piezo bimorph mirrors are versatile active optics used on many synchrotron beamlines. However, many bimorphs suffer from the `junction effect': a periodic deformation of the optical surface which causes major aberrations to the reflected X-ray beam. This effect is linked to the construction of such mirrors, where piezo ceramics are glued directly below the thin optical substrate. In order to address this problem, a next-generation bimorph with piezos bonded to the side faces of a monolithic substrate was developed at Thales-SESO and optimized at Diamond Light Source. Using metrology feedback from the Diamond-NOM, the optical slope error was reduced to ∼ 0.5 µrad r.m.s. for a range of ellipses. To maximize usability, a novel holder was built to accommodate the substrate in any orientation. When replacing a first-generation bimorph on a synchrotron beamline, the new mirror significantly improved the size and shape of the reflected X-ray beam. Most importantly, there was no evidence of the junction effect even after eight months of continuous beamline usage. It is hoped that this new design will reinvigorate the use of active bimorph optics at synchrotron and free-electron laser facilities to manipulate and correct X-ray wavefronts.

  11. FABRICATION OF PIEZOELECTRIC BIMORPH USING LEAD ZIRCONATE TITANATE THIN FILM DEPOSITED BY HYDROTHERMAL METHOD

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In order to describe the characteristics of piezoelectric bimorph, properties of lead zirconate titanate (LZT) film are studied by X-ray diffraction (XRD) and scanning eletron microscope (SEM). The ratio of PbTiO3/PbZrO3 in LZT is 53/47, which is around morphotropic phase boundary (MPB). LZT film is composed of cubic particles with the average size of 5 μm. Density of thin film is figured out through the datum measured in experiments. The displacement model used to analyze the driving ability of bimorph is set up, and the effect of elastic intermediate layer is taken into account. Piezoelectric coefficient of LZT film is worked out by using the displacement model. Experiments of driving ability show that deformation of bimorph free end does not increase with times of crystal growth processes and the maximum deformation is obtained after two times crystal growth processes. Finally, the ferroelectric property of the bimorph is investigated and coercive voltage of the bimorph is obtained.

  12. Symmetry Breaking by Surface Blocking: Synthesis of Bimorphic Silver Nanoparticles, Nanoscale Fishes and Apples

    Science.gov (United States)

    Cathcart, Nicole; Kitaev, Vladimir

    2016-09-01

    A powerful approach to augment the diversity of well-defined metal nanoparticle (MNP) morphologies, essential for MNP advanced applications, is symmetry breaking combined with seeded growth. Utilizing this approach enabled the formation of bimorphic silver nanoparticles (bi-AgNPs) consisting of two shapes linked by one regrowth point. Bi-AgNPs were formed by using an adsorbing polymer, poly(acrylic acid), PAA, to block the surface of a decahedral AgNP seed and restricting growth of new silver to a single nucleation point. First, we have realized 2-D growth of platelets attached to decahedra producing nanoscale shapes reminiscent of apples, fishes, mushrooms and kites. 1-D bimorphic growth of rods (with chloride) and 3-D bimorphic growth of cubes and bipyramids (with bromide) were achieved by using halides to induce preferential (100) stabilization over (111) of platelets. Furthermore, the universality of the formation of bimorphic nanoparticles was demonstrated by using different seeds. Bi-AgNPs exhibit strong SERS enhancement due to regular cavities at the necks. Overall, the reported approach to symmetry breaking and bimorphic nanoparticle growth offers a powerful methodology for nanoscale shape design.

  13. Symmetry Breaking by Surface Blocking: Synthesis of Bimorphic Silver Nanoparticles, Nanoscale Fishes and Apples

    Science.gov (United States)

    Cathcart, Nicole; Kitaev, Vladimir

    2016-01-01

    A powerful approach to augment the diversity of well-defined metal nanoparticle (MNP) morphologies, essential for MNP advanced applications, is symmetry breaking combined with seeded growth. Utilizing this approach enabled the formation of bimorphic silver nanoparticles (bi-AgNPs) consisting of two shapes linked by one regrowth point. Bi-AgNPs were formed by using an adsorbing polymer, poly(acrylic acid), PAA, to block the surface of a decahedral AgNP seed and restricting growth of new silver to a single nucleation point. First, we have realized 2-D growth of platelets attached to decahedra producing nanoscale shapes reminiscent of apples, fishes, mushrooms and kites. 1-D bimorphic growth of rods (with chloride) and 3-D bimorphic growth of cubes and bipyramids (with bromide) were achieved by using halides to induce preferential (100) stabilization over (111) of platelets. Furthermore, the universality of the formation of bimorphic nanoparticles was demonstrated by using different seeds. Bi-AgNPs exhibit strong SERS enhancement due to regular cavities at the necks. Overall, the reported approach to symmetry breaking and bimorphic nanoparticle growth offers a powerful methodology for nanoscale shape design. PMID:27605125

  14. Fabrication of integrated bimorphs with self aligned tips for optical switching in 2-d photonic crystal waveguides

    NARCIS (Netherlands)

    Chakkalakkal Abdulla, S.M.; Kauppinen, L.J.; Dijkstra, M.; Boer, de M.J.; Berenschot, E.; Ridder, de R.M.; Krijnen, G.J.M.

    2010-01-01

    This paper presents the fabrication technology for a novel class of photonic devices. This technology integrates silicon 2-D photonic crystal (PhC) waveguides and electrostatically actuated bimorph cantilevers with tips that are self-aligned relative to the holes of the PhC. The bimorph cantilevers

  15. Pneumatically Actuated Miniature Peristaltic Vacuum Pumps

    Science.gov (United States)

    Feldman, Sabrina; Feldman, Jason; Svehla, Danielle

    2003-01-01

    Pneumatically actuated miniature peristaltic vacuum pumps have been proposed for incorporation into advanced miniature versions of scientific instruments that depend on vacuum for proper operation. These pumps are expected to be capable of reaching vacuum-side pressures in the torr to millitorr range (from .133 down to .0.13 Pa). Vacuum pumps that operate in this range are often denoted roughing pumps. In comparison with previously available roughing pumps, these pumps are expected to be an order of magnitude less massive and less power-hungry. In addition, they would be extremely robust, and would operate with little or no maintenance and without need for oil or other lubricants. Portable mass spectrometers are typical examples of instruments that could incorporate the proposed pumps. In addition, the proposed pumps could be used as roughing pumps in general laboratory applications in which low pumping rates could be tolerated. The proposed pumps could be designed and fabricated in conventionally machined and micromachined versions. A typical micromachined version (see figure) would include a rigid glass, metal, or plastic substrate and two layers of silicone rubber. The bottom silicone layer would contain shallow pump channels covered by silicone arches that could be pushed down pneumatically to block the channels. The bottom silicone layer would be covered with a thin layer of material with very low gas permeability, and would be bonded to the substrate everywhere except in the channel areas. The top silicone layer would be attached to the bottom silicone layer and would contain pneumatic- actuation channels that would lie crosswise to the pump channels. This version is said to be micromachined because the two silicone layers containing the channels would be fabricated by casting silicone rubber on micromachined silicon molds. The pneumatic-actuation channels would be alternately connected to a compressed gas and (depending on pump design) either to atmospheric

  16. Vibration analysis of magnetostrictive thin-film composite cantilever actuator

    Science.gov (United States)

    Xu, Yan; Shang, Xinchun

    2016-09-01

    The transverse vibration of a composed cantilever beam with magnetostrictive layer is analyzed, which is employed to simulate dynamic response of an actuator. The high-order shear deformation theory of beam and the coupling magnetoelastic constitutive relationship are introduced to construct the governing equations, all interface conditions between magnetostrictive film and elastic substrate as well as the free stress condition on the top and bottom surfaces of the beam can be satisfied. In order to demonstrate validity of the presented mathematical modeling, the verification examples are also given. Furthermore, the effect of geometry and material parameters on dynamic characteristics of magnetostrictive cantilever beam, such as the nature frequency and amplitude, is discussed. Moreover, through computing the magneto-mechanical coupling factor of the beam structure, the variation tendency curves of the factor along with different parameters and frequencies of magnetostrictive cantilever beam actuator have been presented. These numerical results should be useful for the design of beam-type with magnetostrictive thin-film actuators.

  17. Out-of-plane platforms with bi-directional thermal bimorph actuation for transducer applications

    KAUST Repository

    Conchouso, David

    2015-04-01

    This paper reports on the Buckled Cantilever Platform (BCP) that allows the manipulation of the out of plane structures through the adjustment of the pitch angle using thermal bimorph micro-Actuators. Due to the micro-fabrication process used, the bimorph actuators can be designed to move in both: Counter Clockwise (CCW) and Clockwise (CW) directions with a resolution of up to 110 μm/V, with smallest step in the range of nanometers. Thermal and electrical characterization of the thermal bimorph actuators showed low influence in the platforms temperature and low power consumption (< 35μW) mainly due to the natural isolation of the structure. Tip displacements larger than 500μm were achieved. The precise angle adjustment achieved through these mechanisms makes them optimal for a range of different MEMS applications, like optical benches and low frequency sweeping sensors and antennas. © 2015 IEEE.

  18. Determination of maximum power transfer conditions of bimorph piezoelectric energy harvesters

    KAUST Repository

    Ahmad, Mahmoud Al

    2012-07-23

    In this paper, a method to find the maximum power transfer conditions in bimorph piezoelectric-based harvesters is proposed. Explicitly, we derive a closed form expression that relates the load resistance to the mechanical parameters describing the bimorph based on the electromechanical, single degree of freedom, analogy. Further, by taking into account the intrinsic capacitance of the piezoelectric harvester, a more descriptive expression of the resonant frequency in piezoelectric bimorphs was derived. In interest of impartiality, we apply the proposed philosophy on previously published experimental results and compare it with other reported hypotheses. It was found that the proposed method was able to predict the actual optimum load resistance more accurately than other methods reported in the literature. © 2012 American Institute of Physics.

  19. PDMS Based Thermopnuematic Peristaltic Micropump for Microfluidic Systems

    International Nuclear Information System (INIS)

    A thermopnuematic peristaltic micropump for controlling micro litters of fluid was designed and fabricated from multi-stack PDMS structure on glass substrate. Pump structure consists of inlet and outlet, microchannel, three thermopneumatic actuation chambers, and three heaters. In microchannel, fluid is controlled and pumped by peristaltic motion of actuation diaphragm. Actuation diaphragm can bend up and down by exploiting air expansion that is induced by increasing heater temperature. The micropump characteristics were measured as a function of applied voltage and frequency. The flow rate was determined by periodically recording the motion of fluid at Nanoport output and computing flow volume from height difference between consecutive records. From the experiment, an optimum flow rate of 0.82 μl/min is obtained under 14 V three-phase input voltages at 0.033 Hz operating frequency

  20. Peristaltic particle transport using the Lattice Boltzmann method

    Energy Technology Data Exchange (ETDEWEB)

    Connington, Kevin William [Los Alamos National Laboratory; Kang, Qinjun [Los Alamos National Laboratory; Viswanathan, Hari S [Los Alamos National Laboratory; Abdel-fattah, Amr [Los Alamos National Laboratory; Chen, Shiyi [JOHNS HOPKINS UNIV.

    2009-01-01

    Peristaltic transport refers to a class of internal fluid flows where the periodic deformation of flexible containing walls elicits a non-negligible fluid motion. It is a mechanism used to transport fluid and immersed solid particles in a tube or channel when it is ineffective or impossible to impose a favorable pressure gradient or desirous to avoid contact between the transported mixture and mechanical moving parts. Peristaltic transport occurs in many physiological situations and has myriad industrial applications. We focus our study on the peristaltic transport of a macroscopic particle in a two-dimensional channel using the lattice Boltzmann method. We systematically investigate the effect of variation of the relevant dimensionless parameters of the system on the particle transport. We find, among other results, a case where an increase in Reynolds number can actually lead to a slight increase in particle transport, and a case where, as the wall deformation increases, the motion of the particle becomes non-negative only. We examine the particle behavior when the system exhibits the peculiar phenomenon of fluid trapping. Under these circumstances, the particle may itself become trapped where it is subsequently transported at the wave speed, which is the maximum possible transport in the absence of a favorable pressure gradient. Finally, we analyze how the particle presence affects stress, pressure, and dissipation in the fluid in hopes of determining preferred working conditions for peristaltic transport of shear-sensitive particles. We find that the levels of shear stress are most hazardous near the throat of the channel. We advise that shear-sensitive particles should be transported under conditions where trapping occurs as the particle is typically situated in a region of innocuous shear stress levels.

  1. Effects of Magnetic Field and an Endoscope on Peristaltic Motion

    Directory of Open Access Journals (Sweden)

    V. P. Rathod

    2011-01-01

    Full Text Available The Problem of peristaltic transport of a magnetic fluid with variable viscosity through the gap between coaxial tubes where the outer tube is nonuniform with sinusoidal wave traveling down its wall and the inner tube is rigid. The relation between the pressure gradient and friction force on the inner and outer tubes is obtained in terms of magnetic and viscosity parameter. The numerical solutions of pressure gradient, outer friction and inner friction force, and flow rate are shown graphically.

  2. Analysis of resonance frequency and pull-in voltages of curled micro-bimorph cantilevers

    NARCIS (Netherlands)

    Abdulla, S.M.C.; Yagubizade, H.; Krijnen, G.J.M.

    2012-01-01

    A systematic study is presented on the modelling, fabrication and measurements of curled micro-bimorph cantilevers, which are composed of a dielectric beam with a metal electrode layer coated on top. The device, having stress-induced upward curvature in the electrical off-state, functions as a verti

  3. Non-linear electromechanical behaviour of piezoelectric bimorph actuators: influence on performance and lifetime

    NARCIS (Netherlands)

    Ende, D.A. van den; Bos, B.; Groen, W.A.

    2009-01-01

    Piezoelectric bimorph bender actuators find application number of areas, ranging from automotive to health care. High voltage operation in harsh environments poses ever more stringent demands on functionality and lifetime. In these high performance benders, the trade-off between functionality and li

  4. Thermal stability test and analysis of a 20-actuator bimorph deformable mirror

    Institute of Scientific and Technical Information of China (English)

    Ning Yu; Zhou Hong; Yu Hao; Rao Chang-Hui; Jiang Wen-Han

    2009-01-01

    One of the important characteristic of adaptive mirrors is the thermal stability of surface flatness. In this paper, the thermal stability from 13℃ to 25℃ of a 20-actuator bimorph deformable mirror is tested by a Shack-Hartmann wavefront sensor. Experimental results show that, the surface P-V of bimorph increases nearly linearly with ambient temperature. The ratio is 0.11 μm/℃ and the major component of surface displacement is defocused, compared with which, astigmatism, coma and spherical aberration contribute very small. Besides, a finite element model is built up to analyse the influence of thickness, thermal expansion coefficient and Young's modulus of materials on thermal stability. Calculated results show that bimorph has the best thermal stability when the materials have the same thermal expansion coefficient. And when the thickness ratio of glass to PZT is 3 and Young's modulus ratio is approximately 0.4, the surface instability behaviour of the bimorph manifests itself most severely.

  5. Plucked piezoelectric bimorphs for knee-joint energy harvesting: modelling and experimental validation

    Science.gov (United States)

    Pozzi, Michele; Zhu, Meiling

    2011-05-01

    The modern drive towards mobility and wireless devices is motivating intensive research in energy harvesting technologies. To reduce the battery burden on people, we propose the adoption of a frequency up-conversion strategy for a new piezoelectric wearable energy harvester. Frequency up-conversion increases efficiency because the piezoelectric devices are permitted to vibrate at resonance even if the input excitation occurs at much lower frequency. Mechanical plucking-based frequency up-conversion is obtained by deflecting the piezoelectric bimorph via a plectrum, then rapidly releasing it so that it can vibrate unhindered; during the following oscillatory cycles, part of the mechanical energy is converted into electrical energy. In order to guide the design of such a harvester, we have modelled with finite element methods the response and power generation of a piezoelectric bimorph while it is plucked. The model permits the analysis of the effects of the speed of deflection as well as the prediction of the energy produced and its dependence on the electrical load. An experimental rig has been set up to observe the response of the bimorph in the harvester. A PZT-5H bimorph was used for the experiments. Measurements of tip velocity, voltage output and energy dissipated across a resistor are reported. Comparisons of the experimental results with the model predictions are very successful and prove the validity of the model.

  6. Modeling of the Through-the-Thickness Electric Potentials of a Piezoelectric Bimorph Using the Spectral Element Method

    Directory of Open Access Journals (Sweden)

    Xingjian Dong

    2014-02-01

    Full Text Available An efficient spectral element (SE with electric potential degrees of freedom (DOF is proposed to investigate the static electromechanical responses of a piezoelectric bimorph for its actuator and sensor functions. A sublayer model based on the piecewise linear approximation for the electric potential is used to describe the nonlinear distribution of electric potential through the thickness of the piezoelectric layers. An equivalent single layer (ESL model based on first-order shear deformation theory (FSDT is used to describe the displacement field. The Legendre orthogonal polynomials of order 5 are used in the element interpolation functions. The validity and the capability of the present SE model for investigation of global and local responses of the piezoelectric bimorph are confirmed by comparing the present solutions with those obtained from coupled 3-D finite element (FE analysis. It is shown that, without introducing any higher-order electric potential assumptions, the current method can accurately describe the distribution of the electric potential across the thickness even for a rather thick bimorph. It is revealed that the effect of electric potential is significant when the bimorph is used as sensor while the effect is insignificant when the bimorph is used as actuator, and therefore, the present study may provide a better understanding of the nonlinear induced electric potential for bimorph sensor and actuator.

  7. Mems-based pzt/pzt bimorph thick film vibration energy harvester

    DEFF Research Database (Denmark)

    Xu, Ruichao; Lei, Anders; Dahl-Petersen, Christian;

    2011-01-01

    We describe fabrication and characterization of a significantly improved version of a MEMS-based PZT/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass. The main advantage of bimorph vibration energy harvesters is that strain energy is not lost in mechanical...... support materials since only PZT is strained, and thus it has a potential for significantly higher output power. An improved process scheme for the energy harvester resulted in a robust fabrication process with a record high fabrication yield of 98.6%. Moreover, the robust fabrication process allowed...... a high pressure treatment of the screen printed PZT thick films prior to sintering, improving the PZT thick film performance and harvester power output reaches 37.1 μW at 1 g....

  8. MODELLING AND OPTIMISATION OF A BIMORPH PIEZOELECTRIC CANTILEVER BEAM IN AN ENERGY HARVESTING APPLICATION

    Directory of Open Access Journals (Sweden)

    CHUNG KET THEIN

    2016-02-01

    Full Text Available Piezoelectric materials are excellent transducers in converting vibrational energy into electrical energy, and vibration-based piezoelectric generators are seen as an enabling technology for wireless sensor networks, especially in selfpowered devices. This paper proposes an alternative method for predicting the power output of a bimorph cantilever beam using a finite element method for both static and dynamic frequency analyses. Experiments are performed to validate the model and the simulation results. In addition, a novel approach is presented for optimising the structure of the bimorph cantilever beam, by which the power output is maximised and the structural volume is minimised simultaneously. Finally, the results of the optimised design are presented and compared with other designs.

  9. Fast optimization of a bimorph mirror using x-ray grating interferometry.

    Science.gov (United States)

    Wang, Hongchang; Sawhney, Kawal; Berujon, Sebastien; Sutter, John; Alcock, Simon G; Wagner, Ulrich; Rau, Christoph

    2014-04-15

    An x-ray grating interferometer was employed for in situ optimization of an x-ray bimorph mirror. Unlike many other at-wavelength techniques, only a single interferogram image, captured out of the focal plane, is required, enabling the optical surface to be quickly optimized. Moiré fringe analysis was used to calculate the wavefront slope error, which is proportional to the mirror's slope error. Using feedback from grating interferometry, the slope error of a bimorph mirror was reduced to <200  nrad (rms) in only two iterations. This technique has the potential to create photon beams with spatially homogeneous intensities for use in synchrotron and free electron laser beam lines.

  10. Fabrication and characterization of MEMS-based PZT/PZT bimorph thick film vibration energy harvesters

    DEFF Research Database (Denmark)

    Xu, Ruichao; Lei, Anders; Dahl-Petersen, Christian;

    2012-01-01

    We describe the fabrication and characterization of a significantly improved version of a microelectromechanical system-based PZT/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass; the harvester is fabricated in a fully monolithic process. The main advantage...... of bimorph vibration energy harvesters is that strain energy is not lost in mechanical support materials since only Pb(ZrxTi1-x)O3 (PZT) is strained; as a result, the effective system coupling coefficient is increased, and thus a potential for significantly higher output power is released. In addition, when...... yield of 98%. The robust fabrication process allowed a high pressure treatment of the screen printed PZT thick films prior to sintering. The high pressure treatment improved the PZT thick film performance and increased the harvester power output to 37.1 μW at 1 g root mean square acceleration. We also...

  11. Optimization of piezoelectric bimorph actuators with active damping for static and dynamic loads

    DEFF Research Database (Denmark)

    Donoso, Alberto; Sigmund, Ole

    2009-01-01

    The paper considers optimal design problems in the context of active damping. More specifically, we are interested in controlling the tip-deflection of a cantilever beam subjected to static and time-harmonic loading on its free extreme. First, the thickness profile of a piezoelectric bimorph...... electric field breakdown. Results are presented for both design variable cases, for static as well as for dynamic excitation for single frequency and frequency intervals....

  12. "Equivalent" material properties for designing ionic polymer metal composite actuators by equivalent bimorph beam theory

    OpenAIRE

    Çilingir, Halime Didem; Cilingir, Halime Didem

    2008-01-01

    This thesis addresses the Ionic Polymer Metal Composite (IPMC) actuators and two “equivalent” materials parameters for their design and performance assessments: electromechanical coupling coefficient and elastic modulus. The “equivalent” parameters not being material constants are derived from equivalent bimorph beam model. The Nafion membrane based IPMC actuator strips of several thicknesses are manufactured by electrochemical platinization method. The effect of the thickness and operating ...

  13. A low frequency piezoelectric power harvester using a spiral-shaped bimorph

    Institute of Scientific and Technical Information of China (English)

    HU Yuantai; HU Hongping; YANG Jiashi

    2006-01-01

    We propose a spiral-shaped piezoelectric bimorph power harvester operating with coupled flexural and extensional vibration modes for applications to low frequency energy sources.A theoretical analysis is performed and the computational results show that the spiral structure has relatively low operating frequency compared to beam power harvesters of the same size.It is found that to optimize the performance of a piezoelectric spiral-shaped harvester careful design is needed.

  14. COUPLED ANALYSIS FOR THE HARVESTING STRUCTURE AND THE MODULATING CIRCUIT IN A PIEZOELECTRIC BIMORPH ENERGY HARVESTER

    Institute of Scientific and Technical Information of China (English)

    Yuantai Hu; Ting Hu; Qing Jiang

    2007-01-01

    The authors analyze a piezoelectric energy harvester as an electro-mechanically coupled system. The energy harvester consists of a piezoelectric bimorph with a concentrated mass attached at one end, called the harvesting structure, an electric circuit for energy storage,and a rectifier that converts the AC output of the harvesting structure into a DC input for the storage circuit. The piezoelectric bimorph is assumed to be driven into flexural vibration by an ambient acoustic source to convert the mechanical energies into electric energies. The analysis indicates that the performance of this harvester, measured by the power density, is characterized by three important non-dimensional parameters, I.e., the non-dimensional inductance of the storage circuit, the non-dimensional aspect ratio (length/thickness) and the non-dimensional end mass of the harvesting structure. The numerical results show that: (1) the power density can be optimized by varying the non-dimensional inductance for each fixed non-dimensional aspect ratio with a fixed non-dimensional end mass; and (2) for a fixed non-dimensional inductance, the power density is maximized if the non-dimensional aspect ratio and the non-dimensional end mass are so chosen that the harvesting structure, consisting of both the piezoelectric bimorph and the end mass attached, resonates at the frequency of the ambient acoustic source.

  15. Design of a Compact, Bimorph Deformable Mirror-Based Adaptive Optics Scanning Laser Ophthalmoscope.

    Science.gov (United States)

    He, Yi; Deng, Guohua; Wei, Ling; Li, Xiqi; Yang, Jinsheng; Shi, Guohua; Zhang, Yudong

    2016-01-01

    We have designed, constructed and tested an adaptive optics scanning laser ophthalmoscope (AOSLO) using a bimorph mirror. The simulated AOSLO system achieves diffraction-limited criterion through all the raster scanning fields (6.4 mm pupil, 3° × 3° on pupil). The bimorph mirror-based AOSLO corrected ocular aberrations in model eyes to less than 0.1 μm RMS wavefront error with a closed-loop bandwidth of a few Hz. Facilitated with a bimorph mirror at a stroke of ±15 μm with 35 elements and an aperture of 20 mm, the new AOSLO system has a size only half that of the first-generation AOSLO system. The significant increase in stroke allows for large ocular aberrations such as defocus in the range of ±600° and astigmatism in the range of ±200°, thereby fully exploiting the AO correcting capabilities for diseased human eyes in the future.

  16. AlN-based piezoelectric bimorph microgenerator utilizing low-level non-resonant excitation

    Science.gov (United States)

    Hampl, Stefan; Cimalla, Volker; Polster, Tobias; Hoffmann, Martin

    2011-06-01

    This work aims for utilizing human ocular motion for the self-sufficient power supply of a minimally invasive implantable monitoring system for intraocular pressure (IOP). With a proven piezoelectric functionality (d33>5 pm/V), nanocrystalline thin films of aluminum nitride (AlN) provide a good capability for micromechanical energy harvesting (EH) in medical applications. Many d31-mode microcantilever architectures are poorly suited for human-induced EH: Resonant mass-spring-damper systems are tested under high, narrow-band excitation frequencies. However, human motions, e.g. vibrations of eyeballs are marked by their low frequency, unpredictable, mainly aperiodic and time-varying signature. Different vibration types and directions are 3-dimensionally superimposed. Saccadic eye movements are favorable for inertial microgenerators because of their high dynamic loading (ω<=1000°/s). Our generator concept (symmetric active/active-parallel-bimorph cantilever) enables a high structural compliance by maximizing the piezoactive volume at very low cantilever thicknesses (<1 μm). An increased length and seismic mass enable an effective excitation by low-level aperiodic vibrations such as saccadic acceleration impulses. Analytic calculations and FEA-simulations investigate the potential distribution and transient response of different bimorph structures (length 200- 1000 μm, width 20-200 μm) on broadband vibrations. First released monomorph and bimorph structures show very low resonant frequencies and an adequate robustness.

  17. Streamline topologies and their bifurcations for mixed convective peristaltic flow

    Directory of Open Access Journals (Sweden)

    Z. Asghar

    2015-09-01

    Full Text Available In this work our focus is on streamlines patterns and their bifurcations for mixed convective peristaltic flow of Newtonian fluid with heat transfer. The flow is considered in a two dimensional symmetric channel and the governing equations are simplified under widely taken assumptions of large wavelength and low Reynolds number in a wave frame of reference. In order to study the streamlines patterns, a system of nonlinear autonomous differential equations are established and dynamical systems approach is used to discuss the local bifurcations and their topological changes. We have discussed all types of bifurcations and their topological changes are presented graphically. We found that the vortices contract along the vertical direction whereas they expand along horizontal direction. A global bifurcations diagram is used to summarize the bifurcations. The trapping and backward flow regions are mainly affected by increasing Grashof number and constant heat source parameter in such a way that trapping region increases whereas backward flow region shrinks.

  18. Peristaltic Transport of a Couple Stress Fluid : Some Physiological Applications

    CERN Document Server

    Maiti, S

    2010-01-01

    The present paper deals with a theoretical investigation of the peristaltic transport of a couple stress fluid in a porous channel. The study is motivated towards the physiological flow of blood in the micro-circulatory system, by taking account of the particle size effect. The velocity, pressure gradient, stream function and frictional force of blood are investigated, when the Reynolds number is small and the wavelength is large, by using appropriate analytical and numerical methods. Effects of different physical parameters reflecting porosity, Darcy number, couple stress parameter as well as amplitude ratio on velocity profiles, pumping action and frictional force, streamlines pattern and trapping of blood are studied with particular emphasis. The computational results are presented in graphical form. The results are found to be in good agreement with those of Shapiro et. al \\cite{r25} that was carried out for a non-porous channel in the absence of couple stress effect. The present study puts forward an imp...

  19. Development of Stepper motor based Two DOF Robotic Arm Transferring Liquid using Peristaltic Pump

    OpenAIRE

    Padma Thiagarajan; Sudha Ramasamy; Karthikesh.R; Manikandan.P

    2013-01-01

    The aim of this work is to transfer liquid contents from one micro cell to another using two stepper motors and a peristaltic pump. There are two objectives here. One is to develop a low cost roboticarm using stepper motors. The second objective is the control and calibration of the peristaltic pump. All parts are controlled and operated by their respective microcontrollers. Fulfillment of both the objectives leads to an integrated system to transfer liquids from one cell to another. The end ...

  20. Dynamic simulation of a peristaltic micropump considering coupled fluid flow and structural motion

    OpenAIRE

    Lin, Qiao; Yang, Bozhi; Xie, Jun; Tai, Yu-Chong

    2007-01-01

    This paper presents lumped-parameter simulation of dynamic characteristics of peristaltic micropumps. The pump consists of three pumping cells connected in series, each of which is equipped with a compliant diaphragm that is electrostatically actuated in a peristaltic sequence to mobilize the fluid. Diaphragm motion in each pumping cell is first represented by an effective spring subjected to hydrodynamic and electrostatic forces. These cell representations are then used to construct a system...

  1. Peristaltic Flow of Phan-Thien-Tanner Fluid in an Asymmetric Channel with Porous Medium

    OpenAIRE

    Kuppalapalle Vajravelu; S.Sreenadh; Lakshminarayana, P; G. Sucharitha; Rashidi, M. M.

    2016-01-01

    This paper deals with peristaltic transport of Phan-Thien-Tanner fluid in an asymmetric channel induced by sinusoidal peristaltic waves traveling down the flexible walls of the channel. The flow is investigated in a wave frame of reference moving with the velocity of the waveby using the long wavelength and low Reynolds number approximations.The nonlinear governing equations are solved employing a perturbation method by choosing as the perturbation parameter. The expressions for velocity, s...

  2. Sensitivity Enhancement in Magnetic Sensors Based on Ferroelectric-Bimorphs and Multiferroic Composites.

    Science.gov (United States)

    Sreenivasulu, Gollapudi; Qu, Peng; Petrov, Vladimir; Qu, Hongwei; Srinivasan, Gopalan

    2016-01-01

    Multiferroic composites with ferromagnetic and ferroelectric phases have been studied in recent years for use as sensors of AC and DC magnetic fields. Their operation is based on magneto-electric (ME) coupling between the electric and magnetic subsystems and is mediated by mechanical strain. Such sensors for AC magnetic fields require a bias magnetic field to achieve pT-sensitivity. Novel magnetic sensors with a permanent magnet proof mass, either on a ferroelectric bimorph or a ferromagnetic-ferroelectric composite, are discussed. In both types, the interaction between the applied AC magnetic field and remnant magnetization of the magnet results in a mechanical strain and a voltage response in the ferroelectric. Our studies have been performed on sensors with a Nd-Fe-B permanent magnet proof mass on (i) a bimorph of oppositely-poled lead zirconate titanate (PZT) platelets and (ii) a layered multiferroic composite of PZT-Metglas-Ni. The sensors have been characterized in terms of sensitivity and equivalent magnetic noise N. Noise N in both type of sensors is on the order of 200 pT/√Hz at 1 Hz, a factor of 10 improvement compared to multiferroic sensors without a proof mass. When the AC magnetic field is applied at the bending resonance for the bimorph, the measured N ≈ 700 pT/√Hz. We discuss models based on magneto-electro-mechanical coupling at low frequency and bending resonance in the sensors and theoretical estimates of ME voltage coefficients are in very good agreement with the data. PMID:26907290

  3. Sensitivity Enhancement in Magnetic Sensors Based on Ferroelectric-Bimorphs and Multiferroic Composites

    Directory of Open Access Journals (Sweden)

    Gollapudi Sreenivasulu

    2016-02-01

    Full Text Available Multiferroic composites with ferromagnetic and ferroelectric phases have been studied in recent years for use as sensors of AC and DC magnetic fields. Their operation is based on magneto-electric (ME coupling between the electric and magnetic subsystems and is mediated by mechanical strain. Such sensors for AC magnetic fields require a bias magnetic field to achieve pT-sensitivity. Novel magnetic sensors with a permanent magnet proof mass, either on a ferroelectric bimorph or a ferromagnetic-ferroelectric composite, are discussed. In both types, the interaction between the applied AC magnetic field and remnant magnetization of the magnet results in a mechanical strain and a voltage response in the ferroelectric. Our studies have been performed on sensors with a Nd-Fe-B permanent magnet proof mass on (i a bimorph of oppositely-poled lead zirconate titanate (PZT platelets and (ii a layered multiferroic composite of PZT-Metglas-Ni. The sensors have been characterized in terms of sensitivity and equivalent magnetic noise N. Noise N in both type of sensors is on the order of 200 pT/√Hz at 1 Hz, a factor of 10 improvement compared to multiferroic sensors without a proof mass. When the AC magnetic field is applied at the bending resonance for the bimorph, the measured N ≈ 700 pT/√Hz. We discuss models based on magneto-electro-mechanical coupling at low frequency and bending resonance in the sensors and theoretical estimates of ME voltage coefficients are in very good agreement with the data.

  4. Sensitivity Enhancement in Magnetic Sensors Based on Ferroelectric-Bimorphs and Multiferroic Composites.

    Science.gov (United States)

    Sreenivasulu, Gollapudi; Qu, Peng; Petrov, Vladimir; Qu, Hongwei; Srinivasan, Gopalan

    2016-02-20

    Multiferroic composites with ferromagnetic and ferroelectric phases have been studied in recent years for use as sensors of AC and DC magnetic fields. Their operation is based on magneto-electric (ME) coupling between the electric and magnetic subsystems and is mediated by mechanical strain. Such sensors for AC magnetic fields require a bias magnetic field to achieve pT-sensitivity. Novel magnetic sensors with a permanent magnet proof mass, either on a ferroelectric bimorph or a ferromagnetic-ferroelectric composite, are discussed. In both types, the interaction between the applied AC magnetic field and remnant magnetization of the magnet results in a mechanical strain and a voltage response in the ferroelectric. Our studies have been performed on sensors with a Nd-Fe-B permanent magnet proof mass on (i) a bimorph of oppositely-poled lead zirconate titanate (PZT) platelets and (ii) a layered multiferroic composite of PZT-Metglas-Ni. The sensors have been characterized in terms of sensitivity and equivalent magnetic noise N. Noise N in both type of sensors is on the order of 200 pT/√Hz at 1 Hz, a factor of 10 improvement compared to multiferroic sensors without a proof mass. When the AC magnetic field is applied at the bending resonance for the bimorph, the measured N ≈ 700 pT/√Hz. We discuss models based on magneto-electro-mechanical coupling at low frequency and bending resonance in the sensors and theoretical estimates of ME voltage coefficients are in very good agreement with the data.

  5. Sensitivity Enhancement in Magnetic Sensors Based on Ferroelectric-Bimorphs and Multiferroic Composites

    Science.gov (United States)

    Sreenivasulu, Gollapudi; Qu, Peng; Petrov, Vladimir; Qu, Hongwei; Srinivasan, Gopalan

    2016-01-01

    Multiferroic composites with ferromagnetic and ferroelectric phases have been studied in recent years for use as sensors of AC and DC magnetic fields. Their operation is based on magneto-electric (ME) coupling between the electric and magnetic subsystems and is mediated by mechanical strain. Such sensors for AC magnetic fields require a bias magnetic field to achieve pT-sensitivity. Novel magnetic sensors with a permanent magnet proof mass, either on a ferroelectric bimorph or a ferromagnetic-ferroelectric composite, are discussed. In both types, the interaction between the applied AC magnetic field and remnant magnetization of the magnet results in a mechanical strain and a voltage response in the ferroelectric. Our studies have been performed on sensors with a Nd-Fe-B permanent magnet proof mass on (i) a bimorph of oppositely-poled lead zirconate titanate (PZT) platelets and (ii) a layered multiferroic composite of PZT-Metglas-Ni. The sensors have been characterized in terms of sensitivity and equivalent magnetic noise N. Noise N in both type of sensors is on the order of 200 pT/√Hz at 1 Hz, a factor of 10 improvement compared to multiferroic sensors without a proof mass. When the AC magnetic field is applied at the bending resonance for the bimorph, the measured N ≈ 700 pT/√Hz. We discuss models based on magneto-electro-mechanical coupling at low frequency and bending resonance in the sensors and theoretical estimates of ME voltage coefficients are in very good agreement with the data. PMID:26907290

  6. Largest in the world bimorph deformable mirror for high-power laser beam correction

    Science.gov (United States)

    Kudryashov, Alexis; Samarkin, Vadim; Aleksandrov, Alex; Borsoni, Giles; Jitsuno, Takahisa; Romanov, Pavel; Sheldakova, Julia

    2016-03-01

    The deformable mirror with the size of 410x468 mm controlled by the bimorph piezoceramic plates and multilayer piezoceramic stacks was developed. The results of the measurements of the response functions of all the actuators and of the surface shape of the deformable mirror are presented in this paper. The study of the mirror with a Fizeau interferometer and a Shack-Hartmann wavefront sensor has shown that it was possible to improve the flatness of the surface down to a residual roughness of 0.033 μm (RMS). The possibility of correction of the aberrations in high power lasers was numerically demonstrated.

  7. State Feedback Control for Adjusting the Dynamic Behavior of a Piezoactuated Bimorph Atomic Force Microscopy Probe

    CERN Document Server

    Orun, Bilal; Basdogan, Cagatay; Guvenc, Levent

    2012-01-01

    We adjust the transient dynamics of a piezo-actuated bimorph Atomic Force Microscopy (AFM) probe using a state feedback controller. This approach enables us to adjust the quality factor and the resonance frequency of the probe simultaneously. First, we first investigate the effect of feedback gains on dynamic response of the probe and then show that the time constant of the probe can be reduced by reducing its quality factor and/or increasing its resonance frequency to reduce the scan error in tapping mode AFM.

  8. Screen printed PZT/PZT thick film bimorph MEMS cantilever device for vibration energy harvesting

    DEFF Research Database (Denmark)

    Xu, R.; Lei, A.; Christiansen, T. L.;

    2011-01-01

    We present a MEMS-based PZT/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass. The most common piezoelectric energy harvesting devices utilize a cantilever beam of a non piezoelectric material as support beneath or in-between the piezoelectric material....... It provides mechanical support but it also reduces the power output. Our device replaces the support with another layer of the piezoelectric material, and with the absence of an inactive mechanical support all of the stresses induced by the vibrations will be harvested by the active piezoelectric elements....

  9. The effects of first-order strain gradient in micro piezoelectric-bimorph power harvesters.

    Science.gov (United States)

    Hu, Yuantai; Wang, Jining; Yang, Feng; Xue, Huan; Hu, Hongping; Wang, Ji

    2011-04-01

    The effects of first-order strain gradient in micro piezoelectric-bimorph (PB) power harvesters are investigated by including the first-order gradient terms in the energy density functions. For a PB, the gradient effects can be focused on the analysis of the strain gradient effect in the thickness direction through choosing the strains and the electric displacements as the independent constitutive variables. It is shown theoretically that the first-order gradient effects have raised the natural frequency of the PB and effectively enhanced the output power density of the harvester. PMID:21507763

  10. Electrothermally-Actuated Micromirrors with Bimorph Actuators—Bending-Type and Torsion-Type

    Directory of Open Access Journals (Sweden)

    Cheng-Hua Tsai

    2015-06-01

    Full Text Available Three different electrothermally-actuated MEMS micromirrors with Cr/Au-Si bimorph actuators are proposed. The devices are fabricated with the SOIMUMPs process developed by MEMSCAP, Inc. (Durham, NC, USA. A silicon-on-insulator MEMS process has been employed for the fabrication of these micromirrors. Electrothermal actuation has achieved a large angular movement in the micromirrors. Application of an external electric current 0.04 A to the bending-type, restricted-torsion-type, and free-torsion-type mirrors achieved rotation angles of 1.69°, 3.28°, and 3.64°, respectively.

  11. A peristaltic micropump using traveling waves on a polymer membrane

    International Nuclear Information System (INIS)

    We demonstrate a peristaltic micropump that utilizes traveling waves on polymer membranes to transport liquids. This micropump requires no valves and, more importantly, the traveling waves can be generated by a single actuator. These features enable the design of simple, compact devices. This micropump has a hydraulic displacement amplification mechanism (HDAM) that encapsulates an incompressible fluid with flexible polymer membranes made of polydimethyl siloxane. A microchannel is attached to the top side of the HDAM. We used a cantilever-type piezoelectric actuator to oscillate the flexible membrane at the bottom of the HDAM, while the top-side membrane drives the liquid in the channel. This format enables rectangular parallelepiped micropumps as compact as 36 mm long, 10 mm wide and several millimeters high, depending on the channel height. Experiments using the fabricated micropumps equipped with microchannels of various heights revealed that the flow rate was dependent on the ratio of the amplitude of the traveling waves to the height of the fluidic channel. The manufactured micropump could successfully generate a maximum flow rate of 1.5 ml min−1 at 180 mW. (paper)

  12. Peristaltic motion of third grade fluid in curved channel

    Institute of Scientific and Technical Information of China (English)

    S.HINA; M.MUSTAFA; T.HAYAT; F.E.ALSAADI

    2014-01-01

    Analysis is performed to study the slip effects on the peristaltic flow of non-Newtonian fluid in a curved channel with wall properties. The resulting nonlinear partial differential equations are transformed to a single ordinary differential equation in a stream function by using the assumptions of long wavelength and low Reynolds number. This differential equation is solved numerically by employing the built-in routine for solving nonlinear boundary value problems (BVPs) through the software Mathematica. In addition, the analytic solutions for small Deborah number are computed with a regular perturbation technique. It is noticed that the symmetry of bolus is destroyed in a curved channel. An intensification in the slip effect results in a larger magnitude of axial velocity. Further, the size and circulation of the trapped boluses increase with an increase in the slip parameter. Different from the case of planar channel, the axial velocity profiles are tilted towards the lower part of the channel. A comparative study between analytic and numerical solutions shows excellent agreement.

  13. Modeling and simulations of new electrostatically driven, bimorph actuator for high beam steering micromirror deflection angles

    Science.gov (United States)

    Walton, John P.; Coutu, Ronald A.; Starman, LaVern

    2015-02-01

    There are numerous applications for micromirror arrays seen in our everyday lives. From flat screen televisions and computer monitors, found in nearly every home and office, to advanced military weapon systems and space vehicles, each application bringing with it a unique set of requirements. The microelectromechanical systems (MEMS) industry has researched many ways micromirror actuation can be accomplished and the different constraints on performance each design brings with it. This paper investigates a new "zipper" approach to electrostatically driven micromirrors with the intent of improving duel plane beam steering by coupling large deflection angles, over 30°, and a fast switching speed. To accomplish this, an extreme initial deflection is needed which can be reached using high stress bimorph beams. Currently this requires long beams and high voltage for the electrostatic pull in or slower electrothermal switching. The idea for this "zipper" approach is to stack multiple beams of a much shorter length and allow for the deflection of each beam to be added together in order to reach the required initial deflection height. This design requires much less pull-in voltage because the pull-in of one short beam will in turn reduce the height of the all subsequent beams, making it much easier to actuate. Using modeling and simulation software to characterize operations characteristics, different bimorph cantilever beam configurations are explored in order to optimize the design. These simulations show that this new "zipper" approach increases initial deflection as additional beams are added to the assembly without increasing the actuation voltage.

  14. Beam cleanup of a 532-nm pulsed solid-state laser using a bimorph mirror

    Institute of Scientific and Technical Information of China (English)

    Xiang Lei; Bing Xu; Ping Yang; Lizhi Dong; Wenjin Liu; Hu Yan

    2012-01-01

    A successful beam cleanup of a 5-mJ/200-μs pulsed solid-state laser system operating at 532-nm wavelength is demonstrated. In this beam cleanup system, a wave-front sensor-less adaptive optics (AO) system is set up with a 20-element bimorph mirror (BM), a high-voltage amplifier, a charge-coupled device camera, and a control software implementing the stochastic parallel gradient descent (SPGD) algorithm. The brightness of the laser focal spot is improved because the wave-front distortions have been compensated. The performance of this system is presented and the experimental results are analyzed.%A successful beam cleanup of a 5-mJ/200-μs pulsed solid-state laser system operating at 532-nm wavelength is demonstrated.In this beam cleanup system,a wave-front sensor-less adaptive optics (AO) system is set up with a 20-element bimorph mirror (BM),a high-voltage amplifier,a charge-coupled device camera,and a control software implementing the stochastic parallel gradient descent (SPGD) algorithm.The brightness of the laser focal spot is improved because the wave-front distortions have been compensated.The performance of this system is presented and the experimental results are analyzed.

  15. An analytical solution for the magneto-electro-elastic bimorph beam forced vibrations problem

    Science.gov (United States)

    Milazzo, A.; Orlando, C.; Alaimo, A.

    2009-08-01

    Based on the Timoshenko beam theory and on the assumption that the electric and magnetic fields can be treated as steady, since elastic waves propagate very slowly with respect to electromagnetic ones, a general analytical solution for the transient analysis of a magneto-electro-elastic bimorph beam is obtained. General magneto-electric boundary conditions can be applied on the top and bottom surfaces of the beam, allowing us to study the response of the bilayer structure to electromagnetic stimuli. The model reveals that the magneto-electric loads enter the solution as an equivalent external bending moment per unit length and as time-dependent mechanical boundary conditions through the definition of the bending moment. Moreover, the influences of the electro-mechanic, magneto-mechanic and electromagnetic coupling on the stiffness of the bimorph stem from the computation of the beam equivalent stiffness constants. Free and forced vibration analyses of both multiphase and laminated magneto-electro-elastic composite beams are carried out to check the effectiveness and reliability of the proposed analytic solution.

  16. Construction of a Fish‐like Robot Based on High Performance Graphene/PVDF Bimorph Actuation Materials

    Science.gov (United States)

    Xiao, Peishuang; Yi, Ningbo; Zhang, Tengfei; Chang, Huicong; Yang, Yang; Zhou, Ying

    2016-01-01

    Smart actuators have many potential applications in various areas, so the development of novel actuation materials, with facile fabricating methods and excellent performances, are still urgent needs. In this work, a novel electromechanical bimorph actuator constituted by a graphene layer and a PVDF layer, is fabricated through a simple yet versatile solution approach. The bimorph actuator can deflect toward the graphene side under electrical stimulus, due to the differences in coefficient of thermal expansion between the two layers and the converse piezoelectric effect and electrostrictive property of the PVDF layer. Under low voltage stimulus, the actuator (length: 20 mm, width: 3 mm) can generate large actuation motion with a maximum deflection of about 14.0 mm within 0.262 s and produce high actuation stress (more than 312.7 MPa/g). The bimorph actuator also can display reversible swing behavior with long cycle life under high frequencies. on this basis, a fish‐like robot that can swim at the speed of 5.02 mm/s is designed and demonstrated. The designed graphene‐PVDF bimorph actuator exhibits the overall novel performance compared with many other electromechanical avtuators, and may contribute to the practical actuation applications of graphene‐based materials at a macro scale.

  17. Analytical modeling and experimental verification of vibration-based piezoelectric bimorph beam with a tip-mass for power harvesting

    Science.gov (United States)

    Wang, Hongjin; Meng, Qingfeng

    2013-03-01

    Power harvesting techniques that convert vibration energy into electrical energy through piezoelectric transducers show strong potential for powering smart wireless sensor devices in applications of structural health monitoring. This paper presents an analytical model of the dynamic behavior of an electromechanical piezoelectric bimorph cantilever harvester connected with an AC-DC circuit based on the Euler-Bernoulli beam theory and Hamiltonian theorem. A new cantilevered piezoelectric bimorph structure is proposed in which the plug-type connection between support layer and tip-mass ensures that the gravity center of the tip-mass is collinear with the gravity center of the beam so that the brittle fracture of piezoelectric layers can also be avoided while vibrating with large amplitude. The tip-mass is equated by the inertial force and inertial moment acting at the end of the piezoelectric bimorph beam based on D'Alembert's principle. An AC-DC converting circuit soldered with the piezoelectric elements is also taken into account. A completely new analytic expression of the global behavior of the electromechanical piezoelectric bimorph harvesting system with AC-DC circuit under input base transverse excitation is derived. Moreover, an experimental energy harvester is fabricated and the theoretical analysis and experimental results of the piezoelectric harvester under the input base transverse displacement excitation are validated by using measurements of the absolute tip displacement, electric voltage response, electric current response and electric power harvesting.

  18. An Efficient Spectral Element Model with Electric DOFs for the Static and Dynamic Analysis of a Piezoelectric Bimorph

    Directory of Open Access Journals (Sweden)

    Xingjian Dong

    2014-01-01

    Full Text Available An efficient spectral element (SE model for static and dynamic analysis of a piezoelectric bimorph is proposed. It combines an equivalent single layer (ESL model for the mechanical displacement field with a sublayer approximation for the electric potential. The 2D Gauss-Lobatto-Legendre (GLL shape functions are used to discretize the displacements and then the governing equation of motion is derived following the standard SE method procedure. It is shown numerically that the present SE model can well predict both the global and local responses such as mechanical displacements, natural frequencies, and the electric potentials across the bimorph thickness. In the case of bimorph sensor application, it is revealed that the distribution of the induced electric potential across the thickness does not affect the global natural frequencies much. Furthermore, the effects of the order of Legendre polynomial and the mesh size on the convergence rate are investigated. Comparison of the present results for a bimorph sensor with those from 3D finite element (FE simulations establishes that the present SE model is accurate, robust, and computationally efficient.

  19. Endoscopy analysis for the peristaltic flow of nanofluids containing carbon nanotubes with heat transfer

    Energy Technology Data Exchange (ETDEWEB)

    Akbar, Noreen Sher [National University of Sciences and Technology, Islamabad (Pakistan)

    2015-07-01

    Cu-water nanofluid with carbon nanotubes is considered for the peristaltic flow in an endoscope. The peristaltic flow for nanofluid is modelled considering that the peristaltic rush wave is a sinusoidal wave that propagates along the walls of the tube. The governing equations for the proposed model are simplified by using the assumptions of long-wavelength and low Reynolds number. Exact solutions have been evaluated for velocity, temperature, and pressure gradient. Graphical results for the numerical values of the flow parameters, i.e. Hartmann number M, the solid volume fraction φ of the nanoparticles, Grashof number Gr, heat absorption parameter β, and radius of the inner tube ε, have been presented for the pressure difference, frictional forces, velocity profile, and temperature profile, and trapping phenomena have been discussed at the end of the article.

  20. Portable Valve-less Peristaltic Micro-pump Design and Fabrication

    CERN Document Server

    Yang, H; Hu, C -C

    2008-01-01

    This paper is to describe a design and fabrication method for a valve-less peristaltic micro-pump. The valve-less peristaltic micro-pump with three membrane chambers in a serial is actuated by three piezoelectric (PZT) actuators. With the fluidic flow design, liquid in the flow channel is pumped to a constant flow speed ranged from 0.4 to 0.48 mm/s. In term of the maximum flow rate of the micro-pump is about 365 mircoliters/min, when the applied voltage is 24V and frequency 50 Hz. Photolithography process was used to fabricate the micro-pump mold. PDMS molding and PDMS bonding method were used to fabricate the micro-channel and actuator chambers. A portable drive controller was designed to control three PZT actuators in a proper sequence to drive the chamber membrane. Then, all parts were integrated into the portable valve-less peristaltic micro-pump system.

  1. Peristaltic transport of Carreau-Yasuda fluid in a curved channel with slip effects.

    Directory of Open Access Journals (Sweden)

    Tasawar Hayat

    Full Text Available The wide occurrence of peristaltic pumping should not be surprising at all since it results physiologically from neuro-muscular properties of any tubular smooth muscle. Of special concern here is to predict the rheological effects on the peristaltic motion in a curved channel. Attention is focused to develop and simulate a nonlinear mathematical model for Carreau-Yasuda fluid. The progressive wave front of peristaltic flow is taken sinusoidal (expansion/contraction type. The governing problem is challenge since it has nonlinear differential equation and nonlinear boundary conditions even in the long wavelength and low Reynolds number regime. Numerical solutions for various flow quantities of interest are presented. Comparison for different flow situations is also made. Results of physical quantities are interpreted with particular emphasis to rheological characteristics.

  2. Peristaltic Pumping of Blood in micro-vessels of Non-uniform Cross-section

    CERN Document Server

    Misra, J C

    2010-01-01

    The paper is devoted to a study of the peristaltic motion of blood in the micro-circulatory system. The vessel is considered of non-uniform cross-section. The progressive peristaltic waves are taken to be of sinusoidal nature. The Reynolds number is considered to be small. Blood is considered to be a Herschel-Bulkley fluid. Of particular concern here is to investigate the effects of amplitude ratio, mean pressure gradient, yield stress and the power law index on the velocity distribution, streamline pattern and wall shear stress. Basing upon the study, extensive numerical calculations has been made. The study reveals that peristaltic pumping as well as velocity and wall shear stress are appreciably affected due to the non-uniform geometry of blood vessels. They are also highly sensitive to the magnitude of the amplitude of the amplitude ratio and the value of the fluid index.

  3. Portable Valve-less Peristaltic Micro-pump Design and Fabrication

    OpenAIRE

    H. Yang; Tsai, T. -H.; Hu, C.-C.

    2008-01-01

    Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/16838); International audience; This paper is to describe a design and fabrication method for a valve-less peristaltic micro-pump. The valve-less peristaltic micro-pump with three membrane chambers in a serial is actuated by three piezoelectric (PZT) actuators. With the fluidic flow design, liquid in the flow channel is pumped to a constant flow speed ranged from 0.4 to 0.48 mm/s. In term of the maximum flo...

  4. Flow Rate Driven by Peristaltic Movement in Plasmodial Tube of Physarum Polycephalum

    Science.gov (United States)

    Yamada, Hiroyasu; Nakagaki, Toshiyuki

    2008-07-01

    We report a theoretical analysis of protoplasmic streaming driven by peristaltic movement in an elastic tube of an amoeba-like organism. The Plasmodium of Physarum polycephalum, a true slime mold, is a large amoeboid organism that adopts a sheet-like form with a tubular network. The network extends throughout the Plasmodium and enables the transport and circulation of chemical signals and nutrients. This tubular flow is driven by periodically propagating waves of active contraction of the tube cortex, a process known as peristaltic movement. We derive the relationship between the phase velocity of the contraction wave and the flow rate, and we discuss the physiological implications of this relationship.

  5. Design and analysis of a connected broadband multi-piezoelectric-bimorph- beam energy harvester.

    Science.gov (United States)

    Zhang, Haifeng; Afzalul, Karim

    2014-06-01

    The rapid growth of remote, wireless, and microelectromechanical system (MEMS) devices over the past decades has motivated the development of a self-powered system that can replace traditional electrochemical batteries. Piezoelectric energy harvesters are ideal for capturing energy from mechanical vibrations in the ambient environment. Numerous studies have been made of this application of piezoelectric energy conversion; however, the narrow frequency operation band has limited its application to generate useful power. In this paper, a broadband energy harvester with an array/matrix of piezoelectric bimorphs connected by springs has been designed and analyzed based on the 1-D piezoelectric beam equations. The predicted result shows that the operational frequency band can be enlarged significantly by carefully adjusting the small end masses, length of the beam and spring stiffness. An optimal selection of the load impedance to realize the maximum power output is discussed. The results provide an important foundation for future broadband energy harvester design.

  6. Design and analysis of a connected broadband multi-piezoelectric-bimorph- beam energy harvester.

    Science.gov (United States)

    Zhang, Haifeng; Afzalul, Karim

    2014-06-01

    The rapid growth of remote, wireless, and microelectromechanical system (MEMS) devices over the past decades has motivated the development of a self-powered system that can replace traditional electrochemical batteries. Piezoelectric energy harvesters are ideal for capturing energy from mechanical vibrations in the ambient environment. Numerous studies have been made of this application of piezoelectric energy conversion; however, the narrow frequency operation band has limited its application to generate useful power. In this paper, a broadband energy harvester with an array/matrix of piezoelectric bimorphs connected by springs has been designed and analyzed based on the 1-D piezoelectric beam equations. The predicted result shows that the operational frequency band can be enlarged significantly by carefully adjusting the small end masses, length of the beam and spring stiffness. An optimal selection of the load impedance to realize the maximum power output is discussed. The results provide an important foundation for future broadband energy harvester design. PMID:24859665

  7. The self-generated peristaltic motion of cascaded pneumatic actuators for micro pumps

    International Nuclear Information System (INIS)

    This paper presents a new actuation mechanism for the self-generated peristaltic motion of cascaded actuators and its application to micro pumps. The operational method is based on the fluidic circuit of an elastic tube. The elastic tube is modeled as a ladder network consisting of fluidic resistances in series and fluidic capacitances in parallel like multi-stage low-pass filters in an electrical circuit. All segments of the lumped model of the elastic tube have different dynamic characteristics because their time constants are different. In other words, all segments should be deformed sequentially like peristaltic motion. This phenomenon has good potential to cause peristaltic motion of the cascaded actuators in response to the application of single-phase pneumatic signals. Analogues between the electrical and fluidic circuits were applied to a pneumatic micro pump with a micro fluidic channel and three pneumatic actuators connecting a unique micro channel for supplying the compressed air. The polymeric micro pumps were fabricated with soft lithography using only polyimethylsiloxsane. The proposed working principle was verified through simulation of the static deformation of the cascaded actuator diaphragms and the actuator, as well as tested experimentally. The dual operational modes of the proposed device (i.e., rubber-seal valve and peristaltic pumping mode) were also verified and successfully demonstrated in a liquid pumping test of the single and double pumps

  8. Development of Stepper motor based Two DOF Robotic Arm Transferring Liquid using Peristaltic Pump

    Directory of Open Access Journals (Sweden)

    Padma Thiagarajan

    2013-02-01

    Full Text Available The aim of this work is to transfer liquid contents from one micro cell to another using two stepper motors and a peristaltic pump. There are two objectives here. One is to develop a low cost roboticarm using stepper motors. The second objective is the control and calibration of the peristaltic pump. All parts are controlled and operated by their respective microcontrollers. Fulfillment of both the objectives leads to an integrated system to transfer liquids from one cell to another. The end effecter of the robotic arm is connected to the peristaltic pump. The pump has two pipes connected to it. Through one pipe it takes in the liquid and through the other pipe it delivers the liquid into the second cell. After transferring one sample of liquid, the arm moves to a cleaning module where the end effecter is cleaned to avoid cross contamination. The robotic arm is built using stepper motors and controlled using Atmega32 microcontroller whereas the peristaltic pump is controlled and calibrated using 8051 microcontroller. The pumping is done with the help of DC motors. As a result, the working of the robotic arm and theperistaltic pump is verified experimentally.

  9. The self-generated peristaltic motion of cascaded pneumatic actuators for micro pumps

    Science.gov (United States)

    Jeong, Ok Chan; Konishi, Satoshi

    2008-08-01

    This paper presents a new actuation mechanism for the self-generated peristaltic motion of cascaded actuators and its application to micro pumps. The operational method is based on the fluidic circuit of an elastic tube. The elastic tube is modeled as a ladder network consisting of fluidic resistances in series and fluidic capacitances in parallel like multi-stage low-pass filters in an electrical circuit. All segments of the lumped model of the elastic tube have different dynamic characteristics because their time constants are different. In other words, all segments should be deformed sequentially like peristaltic motion. This phenomenon has good potential to cause peristaltic motion of the cascaded actuators in response to the application of single-phase pneumatic signals. Analogues between the electrical and fluidic circuits were applied to a pneumatic micro pump with a micro fluidic channel and three pneumatic actuators connecting a unique micro channel for supplying the compressed air. The polymeric micro pumps were fabricated with soft lithography using only polyimethylsiloxsane. The proposed working principle was verified through simulation of the static deformation of the cascaded actuator diaphragms and the actuator, as well as tested experimentally. The dual operational modes of the proposed device (i.e., rubber-seal valve and peristaltic pumping mode) were also verified and successfully demonstrated in a liquid pumping test of the single and double pumps.

  10. Peristaltic transport of a Maxwell fluid in a porous asymmetric channel through a porous medium

    Directory of Open Access Journals (Sweden)

    Safia Akram

    2014-12-01

    Full Text Available The present study investigates the peristaltic flow of a Maxwell fluid in a porous asymmetric channel through a porous medium. An analytical solution has been found using regular perturbation method. The stream function and average mean velocity are obtained. The graphical results are presented to discuss the physical behavior of various parameters appearing in the problem.

  11. Peristaltic flow of a Maxwell fluid in a channel with compliant walls

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Nasir [Department of Mathematics, Quaid-i-Azam University 45320, Islamabad 44000 (Pakistan)], E-mail: nasirali_qau@yahoo.com; Hayat, Tasawar [Department of Mathematics, Quaid-i-Azam University 45320, Islamabad 44000 (Pakistan); Asghar, Saleem [Department of Mathematical Sciences, COMSATS Institute of Information Technology, Islamabad (Pakistan)

    2009-01-15

    This paper describes the peristaltic motion of a non-Newtonian fluid in a channel having compliant boundaries. Constitutive equations for a Maxwell fluid have been used. Perturbation method has been used for the analytic solution. The influence of pertinent parameters is analyzed. Comparison of the present analysis of Maxwell fluid is made with the existing results of viscous fluid.

  12. Slip and heat transfer effects on peristaltic motion of a Carreau fluid in an asymmetric channel

    Energy Technology Data Exchange (ETDEWEB)

    Hayat, Tasawar [Quaid-i-Azam Univ., Islamabad (Pakistan). Dept. of Mathematics; King Saud Univ., Riyadh (Saudi Arabia). Dept. of Mathematics; Saleem, Najma [Quaid-i-Azam Univ., Islamabad (Pakistan). Dept. of Mathematics; Hendi, Awatif A. [Dept. of Physics, Riyadh (Saudi Arabia). Faculty of Science

    2010-12-15

    An analysis has been carried out for peristaltic flow and heat transfer of a Carreau fluid in an asymmetric channel with slip effect. The governing problem is solved under long wavelength approximation. The variations of pertinent dimensionless parameters on temperature are discussed. Pumping and trapping phenomena are studied. (orig.)

  13. Slip effects on the magnetohydrodynamic peristaltic flow of a maxwell fluid

    Energy Technology Data Exchange (ETDEWEB)

    Hayat, Tasawar [Quiad-I-Azam Univ., Islamabad (Pakistan). Dept. of Mathematics; King Saud Univ., Riyadh (Saudi Arabia). Dept. of Mathematics; Hina, Sadia [Quiad-I-Azam Univ., Islamabad (Pakistan). Dept. of Mathematics; Hendi, Awatif A. [Dept. of Physics, Riyadh (Saudi Arabia). Faculty of Science

    2010-12-15

    The influence of slip on the magnetohydrodynamic (MHD) peristaltic flow in a planar channel with compliant walls is examined. An incompressible Maxwell fluid saturates the porous medium. An established solution is valid for small wave number. The mathematical expression of the stream function is presented. Several interesting flow parameters are sketched and examined. (orig.)

  14. A mathematical model for the peristaltic flow of chyme movement in small intestine.

    Science.gov (United States)

    Tripathi, Dharmendra

    2011-10-01

    A mathematical model based on viscoelastic fluid (fractional Oldroyd-B model) flow is considered for the peristaltic flow of chyme in small intestine, which is assumed to be in the form of an inclined cylindrical tube. The peristaltic flow of chyme is modeled more realistically by assuming that the peristaltic rush wave is a sinusoidal wave, which propagates along the tube. The governing equations are simplified by making the assumptions of long wavelength and low Reynolds number. Analytical approximate solutions of problem are obtained by using homotopy analysis method and convergence of the obtained series solution is properly checked. For the realistic values of the emerging parameters such as fractional parameters, relaxation time, retardation time, Reynolds number, Froude number and inclination of tube, the numerical results for the pressure difference and the frictional force across one wavelength are computed and discussed the roles played by these parameters during the peristaltic flow. On the basis of this study, it is found that the first fractional parameter, relaxation time and Froude number resist the movement of chyme, while, the second fractional parameter, retardation time, Reynolds number and inclination of tube favour the movement of chyme through the small intestine during pumping. It is further revealed that size of trapped bolus reduces with increasing the amplitude ratio whereas it is unaltered with other parameters. PMID:21802431

  15. Peristaltic Flow of Phan-Thien-Tanner Fluid in an Asymmetric Channel with Porous Medium

    Directory of Open Access Journals (Sweden)

    Kuppalapalle Vajravelu

    2016-01-01

    Full Text Available This paper deals with peristaltic transport of Phan-Thien-Tanner fluid in an asymmetric channel induced by sinusoidal peristaltic waves traveling down the flexible walls of the channel. The flow is investigated in a wave frame of reference moving with the velocity of the waveby using the long wavelength and low Reynolds number approximations.The nonlinear governing equations are solved employing a perturbation method by choosing as the perturbation parameter. The expressions for velocity, stream function and pressure gradient are obtained. The features of the flow characteristics are analyzed through graphs and the obtained results are discussed in detail. It is noticed that the peristaltic pumping gets reduced due to an increase in the phase difference of the traveling waves. It is also observed that the size of the trapping bolus is a decreasing function of the permeability parameter and the Weissenberg number. Furthermore, the results obtained for the flow characteristics reveal many interesting behaviors that warrant further study on the non-Newtonian fluid phenomena, especially the Peristaltic flow phenomena.

  16. Mechano-optical switching in a mems integrated photonic crystal slab waveguide

    NARCIS (Netherlands)

    Abdulla, S.M.C.; Kauppinen, L.J.; Dijkstra, M.A.; Berenschot, J.W.; Boer, de M.J.; Ridder, de R.M.; Krijnen, G.J.M.

    2011-01-01

    A photonic crystal slab waveguide (PhC-WG) with an integrated MEMS bimorph cantilever actuator has been successfully fabricated using deep UV lithography and surface micromaching techniques. The cantilever is equipped with tips that are self-aligned with respect to the holes of the PhC-WG such that

  17. Active control of flow noise sources in turbulent boundary layer on a flat-plate using piezoelectric bimorph film

    Energy Technology Data Exchange (ETDEWEB)

    Song, Woo Seog; Lee, Seung Bae [Inha University, Incheon (Korea, Republic of); Shin, Dong Shin [Hongik University, Seoul (Korea, Republic of); Na, Yang [Konkuk University, Seoul (Korea, Republic of)

    2006-11-15

    The piezoelectric bimorph film, which, as an actuator, can generate more effective displacement than the usual PVDF film, is used to control the turbulent boundary-layer flow. The change of wall pressures inside the turbulent boundary layer is observed by using the multi-channel microphone array flush-mounted on the surface when actuation at the non-dimensional frequency f{sub b}{sup +} =0.008 and 0.028 is applied to the turbulent boundary layer. The wall pressure characteristics by the actuation to produce local displacement are more dominantly influenced by the size of the actuator module than the actuation frequency. The movement of large-scale turbulent structures to the upper layer is found to be the main mechanism of the reduction in the wall-pressure energy spectrum when the 700{nu}/u{sub {tau}}-long bimorph film is periodically actuated at the non-dimensional frequency f{sub b}{sup +} =0.008 and 0.028. The bimorph actuator is triggered with the time delay for the active forcing at a single frequency when a 1/8' pressure-type, pin-holed microphone sensor detects the large-amplitude pressure event by the turbulent spot. The wall-pressure energy in the late-transitional boundary layer is partially reduced near the convection wavenumber by the open-loop control based on the large amplitude event.

  18. Adaptive Q control for tapping-mode nanoscanning using a piezoactuated bimorph probe.

    Science.gov (United States)

    Gunev, Ihsan; Varol, Aydin; Karaman, Sertac; Basdogan, Cagatay

    2007-04-01

    A new approach, called adaptive Q control, for tapping-mode atomic force microscopy (AFM) is introduced and implemented on a homemade AFM setup utilizing a laser Doppler vibrometer and a piezoactuated bimorph probe. In standard Q control, the effective Q factor of the scanning probe is adjusted prior to the scanning depending on the application. However, there is a trade-off in setting the effective Q factor of an AFM probe. The Q factor is either increased to reduce the tapping forces or decreased to increase the maximum achievable scan speed. Realizing these two benefits simultaneously using standard Q control is not possible. In adaptive Q control, the Q factor of the probe is set to an initial value as in standard Q control, but then modified on the fly during scanning when necessary to achieve this goal. In this article, we present the basic theory behind adaptive Q control, the electronics enabling the online modification of the probe's effective Q factor, and the results of the experiments comparing three different methods: scanning (a) without Q control, (b) with standard Q control, and (c) with adaptive Q control. The results show that the performance of adaptive Q control is superior to the other two methods.

  19. Development of in-series piezoelectric bimorph bending beam actuators for active flow control applications

    Science.gov (United States)

    Chan, Wilfred K.; Clingman, Dan J.; Amitay, Michael

    2016-04-01

    Piezoelectric materials have long been used for active flow control purposes in aerospace applications to increase the effectiveness of aerodynamic surfaces on aircraft, wind turbines, and more. Piezoelectric actuators are an appropriate choice due to their low mass, small dimensions, simplistic design, and frequency response. This investigation involves the development of piezoceramic-based actuators with two bimorphs placed in series. Here, the main desired characteristic was the achievable displacement amplitude at specific driving voltages and frequencies. A parametric study was performed, in which actuators with varying dimensions were fabricated and tested. These devices were actuated with a sinusoidal waveform, resulting in an oscillating platform on which to mount active flow control devices, such as dynamic vortex generators. The main quantification method consisted of driving these devices with different voltages and frequencies to determine their free displacement, blocking force, and frequency response. It was found that resonance frequency increased with shorter and thicker actuators, while free displacement increased with longer and thinner actuators. Integration of the devices into active flow control test modules is noted. In addition to physical testing, a quasi-static analytical model was developed and compared with experimental data, which showed close correlation for both free displacement and blocking force.

  20. Impulse excitation of piezoelectric bimorphs for energy harvesting: a dimensionless model

    Science.gov (United States)

    Pozzi, Michele

    2014-04-01

    Energy harvesting (EH) is a multidisciplinary research area, involving physics, materials science and engineering, with the objective of providing renewable sources of power sufficient to operate targeted low-power applications. Piezoelectric transducers are often used for inertial vibrational as well as direct excitation EH. However, due to the stiffness of the most common material (PZT), compact and light-weight harvesters have high resonant frequencies, making them inefficient at extracting low-frequency power from the environment. The technique of frequency up-conversion, in the form of either plucking or impulse excitation, aims to bridge this frequency gap. In this paper, the technique is modelled analytically with focus on impulse excitation via impact or shock. An analytical model is developed in a standard way starting from the Euler-Bernoulli beam equations adapted to a piezoelectric bimorph. A set of dimensionless variables and parameters is defined and a system of differential equations derived. Here the system is solved numerically for a wide range of the two group parameters present, covering piezoelectric coupling strength between PVDF and PMN-PT. One major result is that the strength of the coupling strongly affects the timescale of the process, but has only a minor effect on the total energy converted. The model can be readily adapted to different excitation profiles.

  1. Development and Validation of an Enhanced Coupled-Field Model for PZT Cantilever Bimorph Energy Harvester

    Directory of Open Access Journals (Sweden)

    Long Zhang

    2013-01-01

    Full Text Available The power source with the limited life span has motivated the development of the energy harvesters that can scavenge the ambient environment energy and convert it into the electrical energy. With the coupled field characteristics of structure to electricity, piezoelectric energy harvesters are under consideration as a means of converting the mechanical energy to the electrical energy, with the goal of realizing completely self-powered sensor systems. In this paper, two previous models in the literatures for predicting the open-circuit and close-circuit voltages of a piezoelectric cantilever bimorph (PCB energy harvester are first described, that is, the mechanical equivalent spring mass-damper model and the electrical equivalent circuit model. Then, the development of an enhanced coupled field model for the PCB energy harvester based on another previous model in the literature using a conservation of energy method is presented. Further, the laboratory experiments are carried out to evaluate the enhanced coupled field model and the other two previous models in the literatures. The comparison results show that the enhanced coupled field model can better predict the open-circuit and close-circuit voltages of the PCB energy harvester with a proof mass bonded at the free end of the structure in order to increase the energy-harvesting level of the system.

  2. Peristaltic Pumping of Blood Through Small Vessels of Varying Cross-Section

    Science.gov (United States)

    Misra, J. C.; Maiti, S.

    2012-11-01

    The paper is devoted to a study of the peristaltic motion of blood in the micro-circulatory system. The vessel is considered to be of varying cross-section. The progressive peristaltic waves are taken to be of sinusoidal nature. Blood is considered to be a Herschel-Bulkley fluid. Of particular concern here is to investigate the effects of amplitude ratio, mean pressure gradient, yield stress and the power law index on the velocity distribution, streamline pattern and wall shear stress. On the basis of the derived analytical expression, extensive numerical calculations have been made. The study reveals that velocity of blood and wall shear stress are appreciably affected due to the non-uniform geometry of blood vessels. They are also highly sensitive to the magnitude of the amplitude ratio and the value of the fluid index.

  3. Efficient worm-like locomotion: slip and control of soft-bodied peristaltic robots

    International Nuclear Information System (INIS)

    In this work, we present a dynamic simulation of an earthworm-like robot moving in a pipe with radially symmetric Coulomb friction contact. Under these conditions, peristaltic locomotion is efficient if slip is minimized. We characterize ways to reduce slip-related losses in a constant-radius pipe. Using these principles, we can design controllers that can navigate pipes even with a narrowing in radius. We propose a stable heteroclinic channel controller that takes advantage of contact force feedback on each segment. In an example narrowing pipe, this controller loses 40% less energy to slip compared to the best-fit sine wave controller. The peristaltic locomotion with feedback also has greater speed and more consistent forward progress. (paper)

  4. Magnetic Field and Gravity Effects on Peristaltic Transport of a Jeffrey Fluid in an Asymmetric Channel

    Directory of Open Access Journals (Sweden)

    A. M. Abd-Alla

    2014-01-01

    Full Text Available In this paper, the peristaltic flow of a Jeffrey fluid in an asymmetric channel has been investigated. Mathematical modeling is carried out by utilizing long wavelength and low Reynolds number assumptions. Closed form expressions for the pressure gradient, pressure rise, stream function, axial velocity, and shear stress on the channel walls have been computed numerically. Effects of the Hartmann number, the ratio of relaxation to retardation times, time-mean flow, the phase angle and the gravity field on the pressure gradient, pressure rise, streamline, axial velocity, and shear stress are discussed in detail and shown graphically. The results indicate that the effect of Hartmann number, ratio of relaxation to retardation times, time-mean flow, phase angle, and gravity field are very pronounced in the peristaltic transport phenomena. Comparison was made with the results obtained in the presence and absence of magnetic field and gravity field.

  5. Design and dynamic characterization of "single-stroke" peristaltic PDMS micropumps.

    Science.gov (United States)

    Lai, Hoyin; Folch, Albert

    2011-01-21

    In this paper, we present a monolithic PDMS micropump that generates peristaltic flow using a single control channel that actuates a group of different-sized microvalves. An elastomeric microvalve design with a raised seat, which improves bonding reliability, is incorporated into the micropump. Pump performance is evaluated based on several design parameters--size, number, and connection of successive microvalves along with control channel pressure at various operating frequencies. Flow rates ranging 0-5.87 µL min(-1) were observed. The micropump design demonstrated here represents a substantial reduction in the number of/real estate taken up by the control lines that are required to run a peristaltic pump, hence it should become a widespread tool for parallel fluid processing in high-throughput microfluidics. PMID:20957288

  6. Development of a peristaltic micropump for bio-medical applications based on mini LIPCA

    OpenAIRE

    Pham, My; Nguyen, Thanh Tung; Goo, Nam Seo

    2008-01-01

    This paper presents the design, fabrication, and experimental characterization of a peristaltic micropump. The micropump is composed of two layers fabricated from polydimethylsiloxane (PDMS) material. The first layer has a rectangular channel and two valve seals. Three rectangular mini lightweight piezo-composite actuators are integrated in the second layer, and used as actuation parts. Two layers are bonded, and covered by two polymethyl methacrylate (PMMA) plates, which help increase the st...

  7. Effect of Wall Properties on the Peristaltic Flow of a Non-Newtonian Fluid

    Directory of Open Access Journals (Sweden)

    Maryiam Javed

    2014-01-01

    Full Text Available The effect of wall properties is analyzed on the peristaltic motion of a Burgers’ fluid. Sinusoidal waves are considered on the channel walls. Small amplitude assumption is taken into account to solve the required boundary value problem. Various flow parameters of interest are sketched and discussed through graphs. Comparative study of the mean velocity for different fluid models is presented the mean velocity is found maximum in viscous fluid when compared with the Maxwell, Oldroyd-B and Burgers’ fluids.

  8. Peristaltic transport of Johnson-Segalman fluid under effect of a magnetic field

    Directory of Open Access Journals (Sweden)

    Moustafa Elshahed

    2005-01-01

    Full Text Available The peristaltic transport of Johnson-Segalman fluid by means of an infinite train of sinusoidal waves traveling along the walls of a two-dimensional flexible channel is investigated. The fluid is electrically conducted by a transverse magnetic field. A perturbation solution is obtained for the case in which amplitude ratio is small. Numerical results are reported for various values of the physical parameters of interest.

  9. Effect of induced magnetic field on peristaltic flow of a micropolar fluid in an asymmetric channel

    OpenAIRE

    Shit, G. C.; Roy, M.; E. Y. K. Ng

    2010-01-01

    Of concern in this paper is an investigation of peristaltic transport of a physiological fluid in an asymmetric channel under long wave length and low-Reynolds number assumptions. The flow is assumed to be incompressible, viscous, electrically conducting micropolar fluid and the effect of induced magnetic field is taken into account. Exact analytical solutions obtained for the axial velocity, microrotation component, stream line pattern, magnetic force function, axial-induced magnetic field a...

  10. A Mathematical Model for Studying the Slip Effect on Peristaltic Motion with Heat and Mass Transfer

    Institute of Scientific and Technical Information of China (English)

    Tasawar Hayat; Najma Saleem; Awatif A. Hendi

    2011-01-01

    A mathematical model is presented with an interest to examine the peristaltic motion in an asymmetric channel by taking into account the slip, heat and mass transfer. Constitutive relationships for a micropolar fluid are used. The solution procedure for nonlinear analysis is given under long wavelength and low Reynolds number approximations. The effects of sundry parameters entering into the expressions of axial velocity,temperature and concentration are explored. Pumping and trapping phenomena are discussed.

  11. Non-Newtonian effects in the peristaltic flow of a Maxwell fluid

    OpenAIRE

    Tsiklauri, D.; Beresnev, I.

    2001-01-01

    We analyzed the effect of viscoelasticity on the dynamics of fluids in porous media by studying the flow of a Maxwell fluid in a circular tube, in which the flow is induced by a wave traveling on the tube wall. The present study investigates novelties brought about into the classic peristaltic mechanism by inclusion of non-Newtonian effects that are important, for example, for hydrocarbons. This problem has numerous applications in various branches of science, including stimulation of fluid f...

  12. Peristaltic Creeping Flow of Power Law Physiological Fluids through a Nonuniform Channel with Slip Effect

    OpenAIRE

    M. K. Chaube; Tripathi, D.; O. Anwar Bég; Shashi Sharma; PANDEY, V.S.

    2015-01-01

    A mathematical study on creeping flow of non-Newtonian fluids (power law model) through a nonuniform peristaltic channel, in which amplitude is varying across axial displacement, is presented, with slip effects included. The governing equations are simplified by employing the long wavelength and low Reynolds number approximations. The expressions for axial velocity, stream function, pressure gradient, and pressure difference are obtained. Computational and numerical results for velocity profi...

  13. Dynamic simulation of a peristaltic micropump considering coupled fluid flow and structural motion

    Science.gov (United States)

    Lin, Qiao; Yang, Bozhi; Xie, Jun; Tai, Yu-Chong

    2007-02-01

    This paper presents lumped-parameter simulation of dynamic characteristics of peristaltic micropumps. The pump consists of three pumping cells connected in series, each of which is equipped with a compliant diaphragm that is electrostatically actuated in a peristaltic sequence to mobilize the fluid. Diaphragm motion in each pumping cell is first represented by an effective spring subjected to hydrodynamic and electrostatic forces. These cell representations are then used to construct a system-level model for the entire pump, which accounts for both cell- and pump-level interactions of fluid flow and diaphragm vibration. As the model is based on first principles, it can be evaluated directly from the device's geometry, material properties and operating parameters without using any experimentally identified parameters. Applied to an existing pump, the model correctly predicts trends observed in experiments. The model is then used to perform a systematic analysis of the impact of geometry, materials and pump loading on device performance, demonstrating its utility as an efficient tool for peristaltic micropump design.

  14. Gastrointestinal monitor: automatic titration of jejunal inflow to match peristaltic outflow.

    Science.gov (United States)

    Moss, Gerald; Posada, Jose G

    2007-06-15

    A peristaltic gradient insures that chyme normally removed from the jejunal feeding site continues to be propelled caudad. The trigger for iatrogenic "feeding intolerance" is the inadvertently overwhelming of the jejunum's peristaltic outflow, even momentarily. Even minimum local stasis can stimulate a vagal reflex response. Motility of the sluggish gut further slows, leading to generalized abdominal distention, malaise, immobility, and impaired respiratory mechanics. Vagal vascular reflexes could explain the 1:1000 incidence of bowel necrosis for jejunally fed patients. We developed a clinical regimen that continuously "checks for residual" at the enteral feeding site, monitoring the adequacy of emptying. The jejunal inflow automatically is titrated to match peristaltic outflow if the latter cannot keep up. Intermittent suction aspirates the feeding catheter into a plastic chamber for 30 s. All swallowed air is removed efficiently within the close confines of the jejunal segment, without wasting digestive juices. The degassed aspirate is returned by gravity with the feedings during the second half of the 1-min cycle, unless incipient excess (>or=20 mL) fluid overflows. Only this relatively small volume of potentially excess fluid is discarded, forestalling the local distention. All patients tolerated immediate feeding without discomfort or abdominal distention, including three that had esophageal resection (including vagotomy) for carcinoma. Postoperative full enteral nutrition can be achieved quickly and safely with minimum attention, despite initially marginal gastrointestinal function. PMID:17509263

  15. Effect of actuation sequence on flow rates of peristaltic micropumps with PZT actuators.

    Science.gov (United States)

    Jang, Ling-Sheng; Shu, Kuan; Yu, Yung-Chiang; Li, Yuan-Jie; Chen, Chiun-Hsun

    2009-02-01

    Many biomedical applications require the administration of drugs at a precise and preferably programmable rate. The flow rate generated by the peristaltic micropumps used in such applications depends on the actuation sequence. Accordingly, the current study performs an analytical and experimental investigation to determine the correlation between the dynamic response of the diaphragms in the micropump and the actuation sequence. A simple analytical model of a peristaltic micropump is established to analyze the shift in the resonant frequency of the diaphragms caused by the viscous damping effect. The analytical results show that this damping effect increases as the oscillation frequency of the diaphragm increases. A peristaltic micropump with three piezoelectric actuators is fabricated on a silicon substrate and is actuated using 2-, 3-, 4- and 6-phase actuation sequences via a driving system comprising a microprocessor and a phase controller. A series of experiments is conducted using de-ionized water as the working fluid to determine the diaphragm displacement and the flow rates induced by each of the different actuation sequences under phase frequencies ranging from 50 Hz to 1 MHz. The results show that the damping effect of actuation sequences influences diaphragm resonant frequency, which in turn affects the profiles of flow rates. PMID:18821016

  16. Particle motion in unsteady two-dimensional peristaltic flow with application to the ureter

    Science.gov (United States)

    Jiménez-Lozano, Joel; Sen, Mihir; Dunn, Patrick F.

    2009-04-01

    Particle motion in an unsteady peristaltic fluid flow is analyzed. The fluid is incompressible and Newtonian in a two-dimensional planar geometry. A perturbation method based on a small ratio of wave height to wavelength is used to obtain a closed-form solution for the fluid velocity field. This analytical solution is used in conjunction with an equation of motion for a small rigid sphere in nonuniform flow taking Stokes drag, virtual mass, Faxén, Basset, and gravity forces into account. Fluid streamlines and velocity profiles are calculated. Theoretical values for pumping rates are compared with available experimental data. An application to ureteral peristaltic flow is considered since fluid flow in the ureter is sometimes accompanied by particles such as stones or bacteriuria. Particle trajectories for parameters that correspond to calcium oxalates for calculosis and Escherichia coli type for bacteria are analyzed. The findings show that retrograde or reflux motion of the particles is possible and bacterial transport can occur in the upper urinary tract when there is a partial occlusion of the wave. Dilute particle mixing is also investigated, and it is found that some of the particles participate in the formation of a recirculating bolus, and some of them are delayed in transit and eventually reach the walls. This can explain the failure of clearing residuals from the upper urinary tract calculi after successful extracorporeal shock wave lithotripsy. The results may also be relevant to the transport of other physiological fluids and industrial applications in which peristaltic pumping is used.

  17. Thermally developing MHD peristaltic transport of nanofluids with velocity and thermal slip effects

    Science.gov (United States)

    Sher Akbar, Noreen; Bintul Huda, A.; Tripathi, D.

    2016-09-01

    We investigate the velocity slip and thermal slip effects on peristaltically driven thermal transport of nanofluids through the vertical parallel plates under the influence of transverse magnetic field. The wall surface is propagating with sinusoidal wave velocity c. The flow characteristics are governed by the mass, momentum and energy conservation principle. Low Reynolds number and large wavelength approximations are taken into consideration to simplify the non-linear terms. Analytical solutions for axial velocity, temperature field, pressure gradient and stream function are obtained under certain physical boundary conditions. Two types of nanoparticles, SiO2 and Ag, are considered for analysis with water as base fluid. This is the first article in the literature that discusses the SiO2 and Ag nanoparticles for a peristaltic flow with variable viscosity. The effects of physical parameters on velocity, temperature, pressure and trapping are discussed. A comparative study of SiO2 nanofluid, Ag nanofluid and pure water is also presented. This model is applicable in biomedical engineering to make thermal peristaltic pumps and other pumping devices like syringe pumps, etc. It is observed that pressure for pure water is maximum and pressure for Ag nanofluid is minimum.

  18. Peristaltic flow in non-uniform vessels of the micro-circulatory system

    CERN Document Server

    Maiti, S

    2013-01-01

    Of concern in the paper is generalized a theoretical study concerning the peristaltic flow of blood in the micro-circulatory system. The vessel is considered to be of non-uniform cross-section and blood to be a non-Newtonian fluid. The progressive wave front of the peristaltic flow is supposed sinusoidal/straight section dominated (SSD) (expansion/contraction type); Reynolds number is considered to be small with reference to the flow of physiological fluids. The non-Newtonian behaviour of blood is illustrated by considering the Herschel-Bulkley fluid model. The objective of the study has been to examine the effect of the effects of amplitude ratio, mean pressure gradient, yield stress and the power law index on the velocity distribution, wall shear stress, streamline pattern and trapping. Considerable quantitative differences between the results obtained for transport in two dimensional channel and an axisymmetric circular tube are noticed. The study shows that peristaltic pumping, flow velocity and wall shea...

  19. Electroelastic modeling and experimental validations of piezoelectric energy harvesting from broadband random vibrations of cantilevered bimorphs

    Science.gov (United States)

    Zhao, S.; Erturk, A.

    2013-01-01

    We present electroelastic modeling, analytical and numerical solutions, and experimental validations of piezoelectric energy harvesting from broadband random vibrations. The modeling approach employed herein is based on a distributed-parameter electroelastic formulation to ensure that the effects of higher vibration modes are included, since broadband random vibrations, such as Gaussian white noise, might excite higher vibration modes. The goal is to predict the expected value of the power output and the mean-square shunted vibration response in terms of the given power spectral density (PSD) or time history of the random vibrational input. The analytical method is based on the PSD of random base excitation and distributed-parameter frequency response functions of the coupled voltage output and shunted vibration response. The first of the two numerical solution methods employs the Fourier series representation of the base acceleration history in an ordinary differential equation solver while the second method uses an Euler-Maruyama scheme to directly solve the resulting electroelastic stochastic differential equations. The analytical and numerical simulations are compared with several experiments for a brass-reinforced PZT-5H bimorph under different random excitation levels. The simulations exhibit very good agreement with the experimental measurements for a range of resistive electrical boundary conditions and input PSD levels. It is also shown that lightly damped higher vibration modes can alter the expected power curve under broadband random excitation. Therefore, the distributed-parameter modeling and solutions presented herein can be used as a more accurate alternative to the existing single-degree-of-freedom solutions for broadband random vibration energy harvesting.

  20. DYNAMIC BIMORPH THERMO-PIEZOELECTRIC BENDERS WITH ARBITRARY SUPPORT LOCATION. PART I: APPLICATION TO ENERGY HARVESTING-ANALYTICAL DERIVATIONS

    Directory of Open Access Journals (Sweden)

    Bagdasaryan G. Y.

    2016-03-01

    Full Text Available A comprehensive theoretical analysis of a dynamic thermo-ferro-electric pre-stressed bimorph energy harvester is performed. The analysis also takes into account pyroelectric and thermal expansion effects. The most general analytical expression for the energy conversation coefficients are presented for bi-layer. These coefficients we derive for more general situation when mechanical, electrical, thermal fields are present. We derive coefficients (transformation coefficients for sensing, actuating, and energy harvesting. As a particular case, we derive an analytical expression for the energy harvesting coefficient due to pyroelectric and thermal expansion effects in a rater general situation. This is a function of material properties, location of boundary conditions, vibration frequency, and in plane compressive/tensile follower force. Numerical simulations of the analytical results are presented. Effects of volume fraction, material properties, applied mechanical loads, and boundary conditions on the harvesting coefficients are introduced in the figures. The results for a cantilever and a simply-supported plate-layer are obtained as particular cases. The result for a low frequency (static system is obtained as a particular case by approaching the vibration frequency to zero. It is shown that volume fraction, material properties, plain compressive/tensile follower force, the location of the boundary conditions, and the vibrational frequency of the bimorph strongly influence the strain distribution, and this in effect influences the charge coefficient and the generation of energy. The proposed model can be extended to thermal energy harvesters of piezoelectric-shape memory alloy (SMA composites.

  1. Tolerability, safety and efficacy of Iloprost infusion without peristaltic pump in systemic sclerosis

    Directory of Open Access Journals (Sweden)

    S. Tosi

    2011-09-01

    Full Text Available Objective. To evaluate safety, tolerability and efficacy on Raynaud’s phenomenon (Rp of iloprost infusion without peristaltic pump in patients with systemic sclerosis (SSc. Patients and methods. The inclusion criteria were diagnosis of SSc, age between 18 and 65 years, presence of Rp, and absence of any controindication to the use of iloprost. The treatment was carried out in a day hospital setting and consisted first of 5 consecutive days of iloprost infusion (from an initial dose of 1.0 ng/Kg/min up to 2 ng/kg/min, and then of 2 days of infusions at the maximum possible dose every 45 days for one year. All of the adverse events were carefully recorded and the changes in the Rp were measured by a 5 grade scale (worsened, unmodified, slightly improved, very improved, disappeared. Results. Thirty-eight SSc patients (all females, mean age 49 years (range 18.5-65, disease duration 1.5 years (range 0.5-10.8 were enrolled in the study. During the first cycle of therapy, 14 avderse events occurred in 11 (28.9% patients and during the next cycles, 3 adverse events were seen in 3 (7.9% patients. In all of the cases they were mild and transient. Rp was considered very improved in 15 (39.5% patients, slightly improved in 13 (34.2%, unmodified in 8 (21% and worse in 2 (5.2%. Discussion. In this study intravenous iloprost without peristaltic pump proved to be safe, well tolerated, and as effective as traditional infusion through peristaltic pump in improving Rp in patients with SSc.

  2. Hall and ion slip effects on peristaltic flow of Jeffrey nanofluid with Joule heating

    Science.gov (United States)

    Hayat, T.; Shafique, Maryam; Tanveer, A.; Alsaedi, A.

    2016-06-01

    This paper addresses mixed convective peristaltic flow of Jeffrey nanofluid in a channel with complaint walls. The present investigation includes the viscous dissipation, thermal radiation and Joule heating. Hall and ion slip effects are also taken into account. Related problems through long wavelength and low Reynolds number are examined for stream function, temperature and concentration. Impacts of thermal radiation, Hartman number, Brownian motion parameter, thermophoresis, Joule heating, Hall and ion slip parameters are investigated in detail. It is observed that velocity increases and temperature decreases with Hall and ion slip parameters. Further the thermal radiation on temperature has qualitatively similar role to that of Hall and ion slip effects.

  3. Peristaltic flow of Johnson-Segalman fluid in asymmetric channel with convective boundary conditions

    Institute of Scientific and Technical Information of China (English)

    H YASMIN; T HAYAT; A ALSAEDI; HH ALSULAMI

    2014-01-01

    This work is concerned with the peristaltic transport of the Johnson-Segalman fluid in an asymmetric channel with convective boundary conditions. The mathematical modeling is based upon the conservation laws of mass, linear momentum, and energy. The resulting equations are solved after long wavelength and low Reynolds number are used. The results for the axial pressure gradient, velocity, and temperature profiles are obtained for small Weissenberg number. The expressions of the pressure gra-dient, velocity, and temperature are analyzed for various embedded parameters. Pumping and trapping phenomena are also explored.

  4. A Peristaltic Micro Pump Driven by a Rotating Motor with Magnetically Attracted Steel Balls

    OpenAIRE

    Zhaoying Zhou; Kang Wu; Xiongying Ye; Min Du

    2009-01-01

    In this paper, we present a membrane peristaltic micro pump driven by a rotating motor with magnetically attracted steel balls for lab-on-a-chip applications. The fabrication process is based on standard soft lithography technology and bonding of a PDMS layer with a PMMA substrate. A linear flow rate range ~490 μL/min was obtained by simply varying the rotation speed of a DC motor, and a maximum back pressure of 592 Pa was achieved at a rotation speed of 43 rpm. The flow rate of the pump can ...

  5. Peristaltic flow with thermal conductivity of H2O + Cu nanofluid and entropy generation

    Directory of Open Access Journals (Sweden)

    Noreen Sher Akbar

    2015-01-01

    Full Text Available In this article, it is opted to investigate the effects of entropy and induced magnetic field for the peristaltic flow of copper water fluid in the asymmetric horizontal channel , the mathematical formulation is presented, the resulting equations are solved exactly. The obtained expressions for pressure gradient , pressure rise, temperature, axial magnetic field, current density, velocity phenomenon entropy generation number and Bejan number are described through graphs for various pertinent parameters. The streamlines are drawn for some physical quantities to discuss the trapping phenomenon.

  6. Peristaltic transport of Conducting Bingham fluid in contact with a Newtonian fluid in a channel

    Directory of Open Access Journals (Sweden)

    M.Arun kumar

    2013-04-01

    Full Text Available Peristaltic pumping by a sinusoidal traveling wave in the walls of a two dimensional channel filled with two immiscible fluids with magnetic effect is investigated. The core region of the channel is occupied by a Bingham fluid where as the peripheral region is occupied by a Newtonian fluid. The flow is examined in a wave frame of reference moving with the velocity of the wave. The expressions for the stream function, the velocity and the pressure rise are obtained. The equation for the interface separating the two fluids is obtained. Numerical results are reported for several of the physical parameters of interest. We observed that the lower values of

  7. Magnetohydrodynamic Peristaltic Flow of a Pseudoplastic Fluid in a Curved Channel

    Science.gov (United States)

    Noreen, Saima; Hayat, Tasawar; Alsaedi, Ahmed

    2013-05-01

    A mathematical model is developed to examine the effects of an induced magnetic field on the peristaltic flow in a curved channel. The non-Newtonian pseudoplastic fluid model is used to depict the combined elastic and viscous properties. The analysis has been carried out in the wave frame of reference, long wavelength and low Reynolds scheme are implemented. A series solution is obtained through perturbation analysis. Results for stream function, pressure gradient, magnetic force function, induced magnetic field, and current density are constructed. The effects of significant parameters on the flow quantities are sketched and discussed.

  8. Radiative Peristaltic Flow of Jeffrey Nanofluid with Slip Conditions and Joule Heating

    Science.gov (United States)

    Hayat, Tasawar; Shafique, Maryam; Tanveer, Anum; Alsaedi, Ahmed

    2016-01-01

    Mixed convection peristaltic flow of Jeffrey nanofluid in a channel with compliant walls is addressed here. The present investigation includes the viscous dissipation, thermal radiation and Joule heating. Whole analysis is performed for velocity, thermal and concentration slip conditions. Related problems through long wavelength and low Reynolds number are examined for stream function, temperature and concentration. Impacts of thermal radiation, Hartman number, Brownian motion parameter, thermophoresis, Joule heating and slip parameters are explored in detail. Clearly temperature is a decreasing function of Hartman number and radiation parameter. PMID:26886919

  9. Magnetohydrodynamic peristaltic flow of a hyperbolic tangent fluid in a vertical asymmetric channel with heat transfer

    Institute of Scientific and Technical Information of China (English)

    Sohail Nadeem; Safia Akram

    2011-01-01

    In the present paper we discuss the magnetohydrodynamic (MHD) peristaltic flow of a hyperbolic tangent fluid model in a vertical asymmetric channel under a zero Reynolds number and long wavelength approximation. Exact solution of the temperature equation in the absence of dissipation term has been computed and the analytical expression for stream function and axial pressure gradient are established. The flow is analyzed in a wave frame of reference moving with the velocity of wave. The expression for pressure rise has been computed numerically. The physical features of pertinent parameters are analyzed by plotting graphs and discussed in detail.

  10. Effect of Slip on Peristaltic Flow of Powell-Eyring Fluid in a Symmetric Channel

    Directory of Open Access Journals (Sweden)

    T. Hayat

    2014-01-01

    Full Text Available Peristaltic flow of non-Newtonian fluid in a symmetric channel with partial slip effect is examined. The non-Newtonian behavior of fluid is characterized by the constitutive equations of Powell-Eyring fluid. The motion is induced by a sinusoidal wave traveling along the flexible walls of channel. The flow is analyzed in a wave frame of reference moving with the velocity of wave. The equations governing the flow are solved by adopting lubrication approach. Series solutions for the stream function and axial pressure gradient are obtained. Impact of slip and other emerging flow parameters is plotted and analyzed graphically.

  11. Mathematical Analysis for Peristaltic Flow of Two Phase Nanofluid in a Curved Channel

    Science.gov (United States)

    Nadeem, S.; Iqra, Shahzadi

    2015-11-01

    This paper describes the theoretical analysis for peristaltic motion of water base nanofluid containing distinct types of the nanoparticles like Cu, TiO2, and Al2O3. Equations of nano fluid are modelled and simplified by constructing the suppositions of low Reynolds number as well as long wave length. The reduced equations are solved exactly. Solutions are represented through graphs. Outcomes for the velocity, temperature, pressure rise and stream lines are analyzed graphically. The work presented here is based on the fictitious values, however some other values can be tested experimentally.

  12. The Mathematical Analysis for Peristaltic Flow of Hyperbolic Tangent Fluid in a Curved Channel

    Institute of Scientific and Technical Information of China (English)

    S.Nadeem; E.N.Maraj

    2013-01-01

    In the present paper,we have investigated the peristaltic flow of hyperbolic tangent fluid in a curved channel.The governing equations of hyperbolic tangent fluid model for curved channel are derived including the effects of curvature.The highly nonlinear partial differential equations are simplified by using the wave frame transformation,long wave length and low Reynolds number assumptions.The reduced nonlinear partial differential equation is solved analytically with the help of homotopy perturbation method (HPM).The physical features of pertinent parameters have been discussed by plotting the graphs of pressure rise and stream functions.

  13. Peristaltic transport of a fractional Burgers' fluid with variable viscosity through an inclined tube

    Science.gov (United States)

    Rachid, Hassan

    2015-12-01

    In the present study,we investigate the unsteady peristaltic transport of a viscoelastic fluid with fractional Burgers' model in an inclined tube. We suppose that the viscosity is variable in the radial direction. This analysis has been carried out under low Reynolds number and long-wavelength approximations. An analytical solution to the problem is obtained using a fractional calculus approach. Figures are plotted to show the effects of angle of inclination, Reynolds number, Froude number, material constants, fractional parameters, parameter of viscosity and amplitude ratio on the pressure gradient, pressure rise, friction force, axial velocity and on the mechanical efficiency.

  14. Peristaltic flow of a Johnson-Segalman fluid through a deformable tube

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yongqi [Darmstadt University of Technology, Department of Mechanical Engineering, Darmstadt (Germany); Universitaet fuer Bodenkultur, Institute of Geotechnical Engineering, Vienna (Austria); Hayat, Tasawar [Quaid-i-Azam University, Mathematics Department, Islamabad (Pakistan); Hutter, Kolumban [ETH Zuerich, VAW, Zuerich (Switzerland)

    2007-09-15

    To understand theoretically the flow properties of physiological fluids we have considered as a model the peristaltic motion of a Johnson-Segalman fluid in a tube with a sinusoidal wave traveling down its wall. The perturbation solution for the stream function is obtained for large wavelength and small Weissenberg number. The expressions for the axial velocity, pressure gradient, and pressure rise per wavelength are also constructed. The general solution of the governing nonlinear partial differential equation is given using a transformation method. The numerical solution is also obtained and is compared with the perturbation solution. Numerical results are demonstrated for various values of the physical parameters of interest. (orig.)

  15. Mixed convection peristaltic flow of third order nanofluid with an induced magnetic field.

    Directory of Open Access Journals (Sweden)

    Saima Noreen

    Full Text Available This research is concerned with the peristaltic flow of third order nanofluid in an asymmetric channel. The governing equations of third order nanofluid are modelled in wave frame of reference. Effect of induced magnetic field is considered. Long wavelength and low Reynolds number situation is tackled. Numerical solutions of the governing problem are computed and analyzed. The effects of Brownian motion and thermophoretic diffusion of nano particles are particularly emphasized. Physical quantities such as velocity, pressure rise, temperature, induced magnetic field and concentration distributions are discussed.

  16. Peristaltic flow in an asymmetric channel with convective boundary conditions and Joule heating

    Institute of Scientific and Technical Information of China (English)

    Abbasi Fahad Munir; Hayat Tasawar; Ahmad Bashir

    2014-01-01

    The peristaltic transport of viscous fluid in an asymmetric channel is concentrated. The channel walls exhibit convective boundary conditions. Both cases of hydrodynamic and magnetohydrodynamic (MHD) fluids are considered. Mathematical analysis has been presented in a wave frame of reference. The resulting problems are non-dimensionalized. Long wavelength and low Reynolds number approximations are employed. Joule heating effect on the thermal equation is retained. Analytic solutions for stream function and temperature are constructed. Numerical integration is carried out for pressure rise per wavelength. Effects of influential flow parameters have been pointed out through graphs.

  17. Effect of Rotation and Magnetic Field through Porous Medium on Peristaltic Transport of a Jeffrey Fluid in Tube

    Directory of Open Access Journals (Sweden)

    S. R. Mahmoud

    2011-01-01

    Full Text Available This paper is concerned with the analysis of peristaltic motion of a Jeffrey fluid in a tube with sinusoidal wave travelling down its wall. The effect of rotation, porous medium, and magnetic field on peristaltic transport of a Jeffrey fluid in tube is studied. The fluid is electrically conducting in the presence of rotation and a uniform magnetic field. An analytic solution is carried out for long wavelength, axial pressure gradient, and low Reynolds number considerations. The results for pressure rise and frictional force per wavelength were obtained, evaluated numerically, and discussed briefly.

  18. Soret and Dufour Effects on MHD Peristaltic Flow of Jeffrey Fluid in a Rotating System with Porous Medium

    Science.gov (United States)

    Hayat, Tasawar; Rafiq, Maimona; Ahmad, Bashir

    2016-01-01

    The objective of present paper is to examine the peristaltic flow of magnetohydrodynamic (MHD) Jeffrey fluid saturating porous space in a channel through rotating frame. Unlike the previous attempts, the flow formulation is based upon modified Darcy's law porous medium effect in Jeffrey fluid situation. In addition the impacts due to Soret and Dufour effects in the radiative peristaltic flow are accounted. Rosseland’s approximation has been utilized for the thermal radiative heat flux. Lubrication approach is implemented for the simplification. Resulting problems are solved for the stream function, temperature and concentration. Graphical results are prepared and analyzed for different parameters of interest entering into the problems. PMID:26808387

  19. Soret and Dufour Effects on MHD Peristaltic Flow of Jeffrey Fluid in a Rotating System with Porous Medium.

    Science.gov (United States)

    Hayat, Tasawar; Rafiq, Maimona; Ahmad, Bashir

    2016-01-01

    The objective of present paper is to examine the peristaltic flow of magnetohydrodynamic (MHD) Jeffrey fluid saturating porous space in a channel through rotating frame. Unlike the previous attempts, the flow formulation is based upon modified Darcy's law porous medium effect in Jeffrey fluid situation. In addition the impacts due to Soret and Dufour effects in the radiative peristaltic flow are accounted. Rosseland's approximation has been utilized for the thermal radiative heat flux. Lubrication approach is implemented for the simplification. Resulting problems are solved for the stream function, temperature and concentration. Graphical results are prepared and analyzed for different parameters of interest entering into the problems. PMID:26808387

  20. Influence of magnetic field on peristaltic flow of a Casson fluid in an asymmetric channel: Application in crude oil refinement

    Science.gov (United States)

    Sher Akbar, Noreen

    2015-03-01

    The influence of magnetic field on peristaltic flow of a Casson fluid model is considered. The model for peristaltic literature is modelled first time. The governing coupled equations are constructed under long wavelength and low Reynold's number approximation. Exact solutions are evaluated for stream function and pressure gradient. The important findings in this study are the variation of the Hartmann number M, Casson fluid parameter ζ and amplitudes a, b, d and ϕ. The velocity field increases due to increase in Hartmann number M near the channel walls while velocity field decreases at the centre of the channel.

  1. A High-Performance, Low-Cost Laser Shutter using a Piezoelectric Cantilever Actuator

    CERN Document Server

    Bowden, W; Baird, P E G; Gill, P

    2016-01-01

    We report the design and characterization of an optical shutter based on a piezoelectric cantilever. Compared to conventional electro-magnetic shutters, the device is intrinsically low power and acoustically quiet. The cantilever position is controlled by a high-voltage op-amp circuit for easy tuning of the range of travel, and mechanical slew rate, which enables a factor of 30 reduction in mechanical noise compared to a rapidly switched device. We achieve shuttering rise and fall times of 11 $\\mu$s, corresponding to mechanical slew rates of 1.3 $\\textrm{ ms}^{-1}$, with an timing jitter of less than 1 $\\mu$s. When used to create optical pulses, we achieve minimum pulse durations of 250 $\\mu$s. The reliability of the shutter was investigated by operating continuously for one week at 10 Hz switching rate. After this period, neither the shutter delay or actuation speed had changed by a notable amount. We also show that the high-voltage electronics can be easily configured as a versatile low-noise, high-bandwidt...

  2. Nanoporous-Gold-Based Hybrid Cantilevered Actuator Dealloyed and Driven by A Modified Rotary Triboelectric Nanogenerator

    Science.gov (United States)

    Li, Xuequan; Liu, Mengmeng; Huang, Baisheng; Liu, Hong; Hu, Weiguo; Shao, Li-Hua; Wang, Zhong Lin

    2016-01-01

    We firstly designed an electrochemical system for dealloying to synthesize nanoporous gold (NPG) and also driving the novel NPG based actuator by utilizing a modified rotary triboelectric nanogenerator (TENG). Compared to the previous reported TENG whose outputs decline due to temperature rising resulting from electrodes friction, the modified TENG with a cooling system has stable output current and voltage increased by 14% and 20%, respectively. The novel cantilevered hybrid actuator characterised by light-weight (ca. 3 mg) and small volume (ca. 30 mm × 2 mm × 10 μm) is driven by a microcontroller modulated TENG with the displacement of 2.2 mm, which is about 106 times larger than that of traditional cantilever using planar surfaces. The energy conversion efficiencies defined as the energy consumed during dealloying and actuation compared with the output of TENG are 47% and 56.7%, respectively. PMID:27063987

  3. The Relation between Peristaltic and Segmental Contraction, Mixing, and Absorption in the Small Intestine

    Science.gov (United States)

    Banco, Gino; Brasseur, James; Wang, Yanxing; Ailiani, Amit; Neuberger, Thomas; Webb, Andrew

    2009-11-01

    The physiology and mechanics of the small intestine originates with lumen-scale fluid motions generated by enterically controlled muscle wall contractions. Although complex in appearance, we have shown with principle component decomposition of gut motion from a rat model that simpler component structure may integrate to produce basic peristaltic and segmental motions. To couple these measured modes with fluid mixing and nutrient absorption we have developed 2-D and axisymmetric models of the gut using the lattice-Boltzmann framework with scalar and second order moving boundary conditions. Previous models indicated that peristalsis is detrimental to absorption and therefore that gut motility is likely bimodal, transitioning between peristalsis and segmental modes to optimize the transport of chyme vs. nutrient absorption. However we have since discovered that more complex control is possible due to potential transitions between ``trapped'' vs. ``nontrapped'' peristaltic fluid motions, depending on occlusion ratio. These transitions lead to an important distinction between 2-D and axisymmetric models and indicate that gut motility may be more finely controlled than previously thought. [Supported by NSF

  4. Slip Effects on Peristaltic Transport of a Particle-Fluid Suspension in a Planar Channel

    Directory of Open Access Journals (Sweden)

    Mohammed H. Kamel

    2015-01-01

    Full Text Available Peristaltic pumping induced by a sinusoidal traveling wave in the walls of a two-dimensional channel filled with a viscous incompressible fluid mixed with rigid spherical particles is investigated theoretically taking the slip effect on the wall into account. A perturbation solution is obtained which satisfies the momentum equations for the case in which amplitude ratio (wave amplitude/channel half width is small. The analysis has been carried out by duly accounting for the nonlinear convective acceleration terms and the slip condition for the fluid part on the wavy wall. The governing equations are developed up to the second order of the amplitude ratio. The zeroth-order terms yield the Poiseuille flow and the first-order terms give the Orr-Sommerfeld equation. The results show that the slip conditions have significant effect within certain range of concentration. The phenomenon of reflux (the mean flow reversal is discussed under slip conditions. It is found that the critical reflux pressure is lower for the particle-fluid suspension than for the particle-free fluid and is affected by slip condition. A motivation of the present analysis has been the hope that such theory of two-phase flow process under slip condition is very useful in understanding the role of peristaltic muscular contraction in transporting biofluid behaving like a particle-fluid mixture. Also the theory is important to the engineering applications of pumping solid-fluid mixture by peristalsis.

  5. Peristaltic Transport of a Rheological Fluid: Model for Movement of Food Bolus Through Esophagus

    CERN Document Server

    Misra, J C

    2011-01-01

    Fluid mechanical peristaltic transport through esophagus has been of concern in the paper. A mathematical model has been developed with an aim to study the peristaltic transport of a rheological fluid for arbitrary wave shapes and tube lengths. The Ostwald-de Waele power law of viscous fluid is considered here to depict the non-Newtonian behaviour of the fluid. The model is formulated and analyzed with the specific aim of exploring some important information concerning the movement of food bolus through the esophagus. The analysis has been carried out by using lubrication theory. The study is particularly suitable for cases where the Reynolds number is small. The esophagus is treated as a circular tube through which the transport of food bolus takes places by periodic contraction of the esophageal wall. Variation of different variables concerned with the transport phenomena such as pressure, flow velocity, particle trajectory and reflux are investigated for a single wave as well as for a train of periodic per...

  6. Williamson Fluid Model for the Peristaltic Flow of Chyme in Small Intestine

    Directory of Open Access Journals (Sweden)

    Sohail Nadeem

    2012-01-01

    Full Text Available Mathematical model for the peristaltic flow of chyme in small intestine along with inserted endoscope is considered. Here, chyme is treated as Williamson fluid, and the flow is considered between the annular region formed by two concentric tubes (i.e., outer tube as small intestine and inner tube as endoscope. Flow is induced by two sinusoidal peristaltic waves of different wave lengths, traveling down the intestinal wall with the same speed. The governing equations of Williamson fluid in cylindrical coordinates have been modeled. The resulting nonlinear momentum equations are simplified using long wavelength and low Reynolds number approximations. The resulting problem is solved using regular perturbation method in terms of a variant of Weissenberg number We. The numerical solution of the problem is also computed by using shooting method, and comparison of results of both solutions for velocity field is presented. The expressions for axial velocity, frictional force, pressure rise, stream function, and axial pressure gradient are obtained, and the effects of various emerging parameters on the flow characteristics are illustrated graphically. Furthermore, the streamlines pattern is plotted, and it is observed that trapping occurs, and the size of the trapped bolus varies with varying embedded flow parameters.

  7. A study of unsteady physiological magneto-fluid flow and heat transfer through a finite length channel by peristaltic pumping.

    Science.gov (United States)

    Tripathi, Dharmendra; Bég, O Anwar

    2012-08-01

    Magnetohydrodynamic peristaltic flows arise in controlled magnetic drug targeting, hybrid haemodynamic pumps and biomagnetic phenomena interacting with the human digestive system. Motivated by the objective of improving an understanding of the complex fluid dynamics in such flows, we consider in the present article the transient magneto-fluid flow and heat transfer through a finite length channel by peristaltic pumping. Reynolds number is small enough and the wavelength to diameter ratio is large enough to negate inertial effects. Analytical solutions for temperature field, axial velocity, transverse velocity, pressure gradient, local wall shear stress, volume flowrate and averaged volume flowrate are obtained. The effects of the transverse magnetic field, Grashof number and thermal conductivity on the flow patterns induced by peristaltic waves (sinusoidal propagation along the length of channel) are studied using graphical plots. The present study identifies that greater pressure is required to propel the magneto-fluid by peristaltic pumping in comparison to a non-conducting Newtonian fluid, whereas, a lower pressure is required if heat transfer is effective. The analytical solutions further provide an important benchmark for future numerical simulations. PMID:23057236

  8. A study of unsteady physiological magneto-fluid flow and heat transfer through a finite length channel by peristaltic pumping.

    Science.gov (United States)

    Tripathi, Dharmendra; Bég, O Anwar

    2012-08-01

    Magnetohydrodynamic peristaltic flows arise in controlled magnetic drug targeting, hybrid haemodynamic pumps and biomagnetic phenomena interacting with the human digestive system. Motivated by the objective of improving an understanding of the complex fluid dynamics in such flows, we consider in the present article the transient magneto-fluid flow and heat transfer through a finite length channel by peristaltic pumping. Reynolds number is small enough and the wavelength to diameter ratio is large enough to negate inertial effects. Analytical solutions for temperature field, axial velocity, transverse velocity, pressure gradient, local wall shear stress, volume flowrate and averaged volume flowrate are obtained. The effects of the transverse magnetic field, Grashof number and thermal conductivity on the flow patterns induced by peristaltic waves (sinusoidal propagation along the length of channel) are studied using graphical plots. The present study identifies that greater pressure is required to propel the magneto-fluid by peristaltic pumping in comparison to a non-conducting Newtonian fluid, whereas, a lower pressure is required if heat transfer is effective. The analytical solutions further provide an important benchmark for future numerical simulations.

  9. Fabrication and performance evaluation of a metal-based bimorph piezoelectric MEMS generator for vibration energy harvesting

    Science.gov (United States)

    Kuo, Chun-Liang; Lin, Shun-Chiu; Wu, Wen-Jong

    2016-10-01

    This paper presents the development of a bimorph microelectromechanical system (MEMS) generator for vibration energy harvesting. The bimorph generator is in cantilever beam structure formed by laminating two lead zirconate titanate thick-film layers on both sides of a stainless steel substrate. Aiming to scavenge vibration energy efficiently from the environment and transform into useful electrical energy, the two piezoelectric layers on the device can be poled for serial and parallel connections to enhance the output voltage or output current respectively. In addition, a tungsten proof mass is bonded at the tip of the device to adjust the resonance frequency. The experimental result shows superior performance the generator. At the 0.5 g base excitation acceleration level, the devices pooled for serial connection and the device poled for parallel connection possess an open-circuit output voltage of 11.6 VP-P and 20.1 VP-P, respectively. The device poled for parallel connection reaches a maximum power output of 423 μW and an output voltage of 15.2 VP-P at an excitation frequency of 143.4 Hz and an externally applied based excitation acceleration of 1.5 g, whereas the device poled serial connection achieves a maximum power output of 413 μW and an output voltage of 33.0 VP-P at an excitation frequency of 140.8 Hz and an externally applied base excitation acceleration of 1.5 g. To demonstrate the feasibility of the MEMS generator for real applications, we finished the demonstration of a self-powered Bluetooth low energy wireless temperature sensor sending readings to a smartphone with only the power from the MEMS generator harvesting from vibration.

  10. A Mathematical Model for Peristaltic Transport of Micro-Polar Fluids

    Directory of Open Access Journals (Sweden)

    S. K. Pandey

    2011-01-01

    Full Text Available A mathematical model has been constructed for peristaltic transport of micro-polar fluid in a circular cylindrical tube of finite length by letting sinusoidal waves propagate along the wall that induce contraction and relaxation but not expansion beyond the natural boundary. Axial and radial velocities and micro-rotation components are formulated for micro-polar fluid transportations by applying the method of long wavelength and low Reynolds number approximations in the analysis. Pressure distribution along the tube length is studied to investigate temporal effects. An in-depth study has been done to learn the effects of coupling number and micro-polar parameter. The effects of coupling number and micro-polar parameter are investigated also on mechanical efficiency, reflux and trapping. A significant difference observed is that unlike integral wave-trains propagating along the tube walls that have identical peaks of pressure, non-integral wave-trains have peaks of different sizes.

  11. Simultaneous effects of slip and wall properties on MHD peristaltic motion of nanofluid with Joule heating

    Science.gov (United States)

    Hayat, T.; Nisar, Z.; Ahmad, B.; Yasmin, H.

    2015-12-01

    This paper is devoted to the magnetohydrodynamic (MHD) peristaltic transport of nanofluid in a channel with wall properties. Flow analysis is addressed in the presence of viscous dissipation, partial slip and Joule heating effects. Mathematical modelling also includes the salient features of Brownian motion and thermophoresis. Both analytic and numerical solutions are provided. Comparison between the solutions is shown in a very good agreement. Attention is focused to the Brownian motion parameter, thermophoresis parameter, Hartman number, Eckert number and Prandtl number. Influences of various parameters on skin friction coefficient, Nusselt and Sherwood numbers are also investigated. It is found that both the temperature and nanoparticles concentration are increasing functions of Brownian motion and thermophoresis parameters.

  12. Development of a peristaltic gas micropump with a single chamber and multiple electrodes

    International Nuclear Information System (INIS)

    This paper reports on the development of a multi-electrode electrostatically driven peristaltic gas micropump. The micropump consists of a single chamber and a flexible diaphragm with a multi-electrode pattern. The single-chamber design is divided into smaller cells by the electrodes; the characteristic operating frequency of the micropump increases as the number of electrodes increases. The flow rate is also observed to increase to maximum before decreasing for larger numbers of electrodes. Whereas the maximum flow rate of a 4-electrode micropump is about 40 µl min−1 at 14 Hz, the maximum flow rate of the 16-electrode micropump is about 250 µl min−1 at 1400 Hz and that of the 32-electrode micropump is 150 µl min−1 at 4000 Hz. (paper)

  13. Development of a Peristaltic Micropump for Bio-Medical Applications Based on Mini LIPCA

    Institute of Scientific and Technical Information of China (English)

    Thanh Tung Nguyen; My Pham; Nam Seo Goo

    2008-01-01

    This paper presents the design, fabrication, and experimental characterization of a peristaltic micropump. The micropump is composed of two layers fabricated from Polydimethylsiloxane (PDMS) material. The first layer has a rectangular channel and two valve seals. Three rectangular mini lightweight piezo-composite actuators are integrated in the second layer, and used as actuation parts.Two layers are bonded, and covered by two Polymethyl Methacrylate (PMMA) plates, which help increase the stiffness of the micropump.A maximum flow rate of 900 uL·min-1 and a maximum backpressure of 1.8 kPa are recorded when water is used as pump liquid. We measured the power consumption of the micropump. The micropump is found to be a prom- ising candidate for bio-medical application due to its bio-compatibility, portability, bidirectionality, and simple effective design.

  14. Peristaltic Transport of Prandtl-Eyring Liquid in a Convectively Heated Curved Channel.

    Science.gov (United States)

    Hayat, Tasawar; Bibi, Shahida; Alsaadi, Fuad; Rafiq, Maimona

    2016-01-01

    Here peristaltic activity for flow of a Prandtl-Eyring material is modeled and analyzed for curved geometry. Heat transfer analysis is studied using more generalized convective conditions. The channel walls satisfy complaint walls properties. Viscous dissipation in the thermal equation accounted. Unlike the previous studies is for uniform magnetic field on this topic, the radial applied magnetic field has been utilized in the problems development. Solutions for stream function (ψ), velocity (u), and temperature (θ) for small parameter β have been derived. The salient features of heat transfer coefficient Z and trapping are also discussed for various parameters of interest including magnetic field, curvature, material parameters of fluid, Brinkman, Biot and compliant wall properties. Main observations of present communication have been included in the conclusion section. PMID:27304458

  15. Mixed Convective Peristaltic Flow of Water Based Nanofluids with Joule Heating and Convective Boundary Conditions.

    Science.gov (United States)

    Hayat, Tasawar; Nawaz, Sadaf; Alsaedi, Ahmed; Rafiq, Maimona

    2016-01-01

    Main objective of present study is to analyze the mixed convective peristaltic transport of water based nanofluids using five different nanoparticles i.e. (Al2O3, CuO, Cu, Ag and TiO2). Two thermal conductivity models namely the Maxwell's and Hamilton-Crosser's are used in this study. Hall and Joule heating effects are also given consideration. Convection boundary conditions are employed. Furthermore, viscous dissipation and heat generation/absorption are used to model the energy equation. Problem is simplified by employing lubrication approach. System of equations are solved numerically. Influence of pertinent parameters on the velocity and temperature are discussed. Also the heat transfer rate at the wall is observed for considered five nanofluids using the two phase models via graphs. PMID:27104596

  16. Effect of induced magnetic field on peristaltic flow of a micropolar fluid in an asymmetric channel

    CERN Document Server

    Shit, G C; Ng, E Y K; 10.1002/cnm.1397

    2010-01-01

    Of concern in this paper is an investigation of peristaltic transport of a physiological fluid in an asymmetric channel under long wave length and low-Reynolds number assumptions. The flow is assumed to be incompressible, viscous, electrically conducting micropolar fluid and the effect of induced magnetic field is taken into account. Exact analytical solutions obtained for the axial velocity, microrotation component, stream line pattern, magnetic force function, axial-induced magnetic field as well as the current density distribution across the channel. The flow phenomena for the pumping characteristics, trapping and reflux are also investigated. The results presented reveal that the velocity decreases with the increase of magnetic field as well as the coupling parameter. Moreover, the trapping fluid can be eliminated by the application of an external magnetic field. Thus, the study bears the promise of important applications in physiological systems.

  17. Peristaltic flow of a reactive viscous fluid through a porous saturated channel and convective cooling conditions

    Science.gov (United States)

    Asghar, S.; Hussain, Q.; Hayat, T.; Alsaedi, A.

    2015-07-01

    This article addresses the heat transfer in a peristaltic flow of a reactive combustible viscous fluid through a porous saturated medium. The flow here is induced because of travelling waves along the channel walls. It is assumed that exothermic chemical reactions take place within the channel under the Arrhenius kinetics and the convective heat exchange with the ambient medium at the surfaces of the channel walls follows Newton's law of cooling. The analysis is carried out in the presence of viscous dissipation and without consumption of the material. The governing equations are formulated by employing the long-wavelength approximation. Closed-form solutions for the stream function, axial velocity, and axial pressure gradient are obtained. It is found that the temperature decreases at high Biot numbers, and the Nusselt number increases with increasing reaction parameter. The Biot number and reaction parameter produce the opposite effects on the Nusselt number.

  18. Simultaneous effects of slip and wall properties on MHD peristaltic motion of nanofluid with Joule heating

    Energy Technology Data Exchange (ETDEWEB)

    Hayat, T. [Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan); Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Department of Mathematics, King Abdulaziz University, P.O. Box 80257, Jeddah 21589 (Saudi Arabia); Nisar, Z. [Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan); Ahmad, B. [Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Department of Mathematics, King Abdulaziz University, P.O. Box 80257, Jeddah 21589 (Saudi Arabia); Yasmin, H., E-mail: qau2011@gmail.com [Department of Mathematics, COMSATS Institute of Information Technology, G.T. Road, Wah Cantt 47040 (Pakistan)

    2015-12-01

    This paper is devoted to the magnetohydrodynamic (MHD) peristaltic transport of nanofluid in a channel with wall properties. Flow analysis is addressed in the presence of viscous dissipation, partial slip and Joule heating effects. Mathematical modelling also includes the salient features of Brownian motion and thermophoresis. Both analytic and numerical solutions are provided. Comparison between the solutions is shown in a very good agreement. Attention is focused to the Brownian motion parameter, thermophoresis parameter, Hartman number, Eckert number and Prandtl number. Influences of various parameters on skin friction coefficient, Nusselt and Sherwood numbers are also investigated. It is found that both the temperature and nanoparticles concentration are increasing functions of Brownian motion and thermophoresis parameters. - Highlights: • Temperature rises when Brownian motion and thermophoresis effects intensify. • Temperature profile increases when thermal slip parameter increases. • Concentration field is a decreasing function of concentration slip parameter. • Temperature decreases whereas concentration increases for Hartman number.

  19. Peristaltic flow of a micropolar fluid with nano particles in small intestine

    Science.gov (United States)

    Akbar, Noreen Sher; Nadeem, S.

    2013-12-01

    The present article analyzed the peristaltic flow of a nanofluid in a uniform tube for micropolar fluid. The governing equations for proposed model are developed in cylindrical coordinates system. The flow is discussed in a wave frame of reference moving with velocity of the wave c. Under the assumptions of longwave length the reduced coupled nonlinear differential equations of momentum, energy, and concentrations are solved by Homotopy perturbation method is used to get the solutions for velocity, temperature, nano particle, microrotation component. The solutions consists Brownian motion number N b, thermophoresis number N t, local temperature Grashof number B r and local nano particle Grashof number G r . The effects of various parameters involved in the problem are investigated for pressure rise, pressure gradient, temperature and concentration profile. Five different waves are taken into account for analysis. Streamlines have been plotted at the end of the article.

  20. Characteristics of Jeffrey fluid model for peristaltic flow of chyme in small intestine with magnetic field

    Science.gov (United States)

    Akbar, Noreen Sher; Nadeem, S.; Lee, Changhoon

    In the present article we have analyzed the Jeffrey fluid model for the peristaltic flow of chyme in the small intestine. We have formulated the problem using two non-periodic sinusoidal waves of different wavelengths propagating with same speed c along the outer wall of the tube. Governing equations for the problem under consideration have been simplified under the assumptions of long wavelength and low Reynolds number approximation (such assumptions are consistent since Re (Reynolds number) is very small and long wavelength approximation also exists in the small intestine). Exact solutions have been calculated for velocity and pressure rise. Physical behavior of different parameters of Jeffrey fluid has been presented graphically for velocity, pressure rise, pressure gradient and frictional forces. The trapping phenomenon is also discussed at the end of the article.

  1. Simulations of peristaltic slip-flow of hydromagnetic bio-fluid in a curved channel

    Science.gov (United States)

    Ali, N.; Javid, K.; Sajid, M.

    2016-02-01

    The influence of slip and magnetic field on transport characteristics of a bio-fluid are analyzed in a curved channel. The problem is modeled in curvilinear coordinate system under the assumption that the wavelength of the peristaltic wave is larger in magnitude compared to the width of the channel. The resulting nonlinear boundary value problem (BVP) is solved using an implicit finite difference technique (FDT). The flow velocity, pressure rise per wavelength and stream function are illustrated through graphs for various values of rheological and geometrical parameters of the problem. The study reveals that a thin boundary layer exists at the channel wall for strong magnetic field. Moreover, small values of Weissenberg number counteract the curvature and make the velocity profile symmetric. It is also observed that pressure rise per wavelength in pumping region increases (decreases) by increasing magnetic field, Weissenberg number and curvature of the channel (slip parameter).

  2. Multi-channel peristaltic pump for microfluidic applications featuring monolithic PDMS inlay

    DEFF Research Database (Denmark)

    Skafte-Pedersen, Peder; Sabourin, David; Dufva, Martin;

    2009-01-01

    The design, fabrication and characterization of a miniaturized, mechanically-actuated 12-channel peristaltic pump for microfluidic applications and built from simple, low-cost materials and fabrication methods is presented. Two pump configurations are tested, including one which reduces pulsating...... flow. Both use a monolithic PDMS pumping inlay featuring three-dimensional geometries favourable to pumping applications and 12 wholly integrated circular channels. Flow rates in the sub-µL min-1 to µL min-1 range were obtained. Channel-to-channel flow rate variability was comparable to a commercial...... pumping system at lower flow rates. The small footprint, 40 mm by 80 mm, of the micropump renders it portable, and allows its use on microscope stages adjacent to microfluidic devices, thus reducing system dead volumes. The micropump's design allows potential use in remote and resource-limited locations...

  3. Peristaltic Transport of Prandtl-Eyring Liquid in a Convectively Heated Curved Channel.

    Directory of Open Access Journals (Sweden)

    Tasawar Hayat

    Full Text Available Here peristaltic activity for flow of a Prandtl-Eyring material is modeled and analyzed for curved geometry. Heat transfer analysis is studied using more generalized convective conditions. The channel walls satisfy complaint walls properties. Viscous dissipation in the thermal equation accounted. Unlike the previous studies is for uniform magnetic field on this topic, the radial applied magnetic field has been utilized in the problems development. Solutions for stream function (ψ, velocity (u, and temperature (θ for small parameter β have been derived. The salient features of heat transfer coefficient Z and trapping are also discussed for various parameters of interest including magnetic field, curvature, material parameters of fluid, Brinkman, Biot and compliant wall properties. Main observations of present communication have been included in the conclusion section.

  4. Peristaltic Pumping near Post-CME Supra-Arcade Current Sheets

    CERN Document Server

    Scott, Roger B; McKenzie, David E

    2013-01-01

    Measurements of temperature and density near supra-arcade current sheets suggest that plasma on unreconnected field lines may experience some degree of "pre-heating" and "pre-densification" prior to their reconnection. Models of patchy reconnection allow for heating and acceleration of plasma along reconnected field lines but do not offer a mechanism for transport of thermal energy across field lines. Here we present a model in which a reconnected flux tube retracts, deforming the surrounding layer of unreconnected field. The deformation creates constrictions that act as peristaltic pumps, driving plasma flow along affected field lines. Under certain circumstances these flows lead to shocks that can extend far out into the unreconnected field, altering the plasma properties in the affected region. These findings have direct implications for observations in the solar corona, particularly in regard to such phenomena as high temperatures near current sheets in eruptive solar flares and wakes seen in the form of ...

  5. Development of a peristaltic micropump for bio-medical applications based on mini LIPCA

    CERN Document Server

    Pham, My; Goo, Nam Seo

    2008-01-01

    This paper presents the design, fabrication, and experimental characterization of a peristaltic micropump. The micropump is composed of two layers fabricated from polydimethylsiloxane (PDMS) material. The first layer has a rectangular channel and two valve seals. Three rectangular mini lightweight piezo-composite actuators are integrated in the second layer, and used as actuation parts. Two layers are bonded, and covered by two polymethyl methacrylate (PMMA) plates, which help increase the stiffness of the micropump. A maximum flow rate of 900 mokroliter per min and a maximum backpressure of 1.8 kPa are recorded when water is used as pump liquid. We measured the power consumption of the micropump. The micropump is found to be a promising candidate for bio-medical application due to its bio-compatibility, portability, bidirectionality, and simple effective design.

  6. A Peristaltic Micro Pump Driven by a Rotating Motor with Magnetically Attracted Steel Balls

    Directory of Open Access Journals (Sweden)

    Zhaoying Zhou

    2009-04-01

    Full Text Available In this paper, we present a membrane peristaltic micro pump driven by a rotating motor with magnetically attracted steel balls for lab-on-a-chip applications. The fabrication process is based on standard soft lithography technology and bonding of a PDMS layer with a PMMA substrate. A linear flow rate range ~490 μL/min was obtained by simply varying the rotation speed of a DC motor, and a maximum back pressure of 592 Pa was achieved at a rotation speed of 43 rpm. The flow rate of the pump can also be adjusted by using steel balls with different diameters or changing the number of balls. Nevertheless, the micro pump can also work in high speed mode. A high back pressure up to 10 kPa was achieved at 500 rpm using a high speed DC motor, and an utmost flow rate up to 5 mL/min was reached.

  7. Peristaltic motion of Johnson-Segalman fluid in a curved channel with slip conditions.

    Directory of Open Access Journals (Sweden)

    Sadia Hina

    Full Text Available Slip effects on the peristaltic transport of Johnson-Segalman fluid through a curved channel have been addressed. The influence of wall properties is also analyzed. Long wavelength and low Reynolds number assumptions have been utilized in the mathematical formulation of the problem. The equations so formed have been solved numerically by shooting method through computational software Mathematica 8. In addition the analytic solution for small Weissenberg number (elastic parameter is computed through a regular perturbation method. An excellent agreement is noticed between the two solutions. The results indicate an increase in the magnitude of velocity with an intensification in the slip effect. Moreover the size and circulation of the trapped boluses increase with an increase in the slip parameter. Unlike the planar channel, the profiles of axial velocity are not symmetric about the central line of the channel.

  8. Peristaltic motion of Johnson-Segalman fluid in a curved channel with slip conditions.

    Science.gov (United States)

    Hina, Sadia; Mustafa, Meraj; Hayat, Tasawar

    2014-01-01

    Slip effects on the peristaltic transport of Johnson-Segalman fluid through a curved channel have been addressed. The influence of wall properties is also analyzed. Long wavelength and low Reynolds number assumptions have been utilized in the mathematical formulation of the problem. The equations so formed have been solved numerically by shooting method through computational software Mathematica 8. In addition the analytic solution for small Weissenberg number (elastic parameter) is computed through a regular perturbation method. An excellent agreement is noticed between the two solutions. The results indicate an increase in the magnitude of velocity with an intensification in the slip effect. Moreover the size and circulation of the trapped boluses increase with an increase in the slip parameter. Unlike the planar channel, the profiles of axial velocity are not symmetric about the central line of the channel.

  9. Simulations of peristaltic slip-flow of hydromagnetic bio-fluid in a curved channel

    Directory of Open Access Journals (Sweden)

    N. Ali

    2016-02-01

    Full Text Available The influence of slip and magnetic field on transport characteristics of a bio-fluid are analyzed in a curved channel. The problem is modeled in curvilinear coordinate system under the assumption that the wavelength of the peristaltic wave is larger in magnitude compared to the width of the channel. The resulting nonlinear boundary value problem (BVP is solved using an implicit finite difference technique (FDT. The flow velocity, pressure rise per wavelength and stream function are illustrated through graphs for various values of rheological and geometrical parameters of the problem. The study reveals that a thin boundary layer exists at the channel wall for strong magnetic field. Moreover, small values of Weissenberg number counteract the curvature and make the velocity profile symmetric. It is also observed that pressure rise per wavelength in pumping region increases (decreases by increasing magnetic field, Weissenberg number and curvature of the channel (slip parameter.

  10. Effects of heat transfer on peristaltic motion of Oldroyd fluid in the presence of inclined magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Afsar Khan, A. [Department of Mathematics and Statistics, FBAS, IIUI, Islamabad (Pakistan); Ellahi, R., E-mail: rahmatellahi@yahoo.com [Department of Mathematics and Statistics, FBAS, IIUI, Islamabad (Pakistan); Department of Mechanical Engineering, Bourns Hall, University of California Riverside, CA 92521 (United States); Mudassar Gulzar, M. [National University of Sciences and Technology, College of Electrical and Mechanical Engineering Islamabad (Pakistan); Sheikholeslami, Mohsen [Department of Mechanical Engineering, Babol University of Technology, Babol (Iran, Islamic Republic of)

    2014-12-15

    In this study the peristaltic motion of Oldroyd fluid in an asymmetric channel is investigated. Mathematical analysis has been carried out in the presence of an inclined magnetic field. Heat transfer is also taken into account. The physical problem is first modeled and then the analytical solutions of coupled equations are developed by regular perturbation method. Assumptions of long wavelength approximation are used. Effects of inclined magnetic field on the axial velocity and temperature are presented. Physical features of pertinent parameters such as wave number δ, Reynolds number Re, Weissenberg number Wi, Prandtl number Pr and Hartmann number M are also discussed graphically at the end of the paper. - Highlights: • This paper analyses heat transfer and inclined magnetic effects in peristaltic motion of Oldroyd fluid. • An asymmetric channel under long wavelength approximation is considered. • Regular perturbation method is used to find analytical solutions. • Effects of sundry parameters are presented through graphs.

  11. Peristaltic Transport of a Physiological Fluid in an Asymmetric Porous Channel in the Presence of an External Magnetic Field

    OpenAIRE

    Misra, J. C.; Maiti, S.; Shit, G. C.

    2010-01-01

    The paper deals with a theoretical investigation of the peristaltic transport of a physiological fluid in a porous asymmetric channel under the action of a magnetic field. The stream function, pressure gradient and axial velocity are studied by using appropriate analytical and numerical techniques. Effects of different physical parameters such as permeability, phase difference, wave amplitude and magnetic parameter on the velocity, pumping characteristics, streamline pattern and trapping are ...

  12. Simultaneous effects of Hall and convective conditions on peristaltic flow of couple-stress fluid in an inclined asymmetric channel

    Indian Academy of Sciences (India)

    T Hayat; Maryam Iqbal; Humaira Yasmin; Fuad E Alsaadi; Huijun Gao

    2015-07-01

    A mathematical model is developed to analyse the peristaltic flow of couple-stress fluid in an inclined asymmetric channel with convective conditions. Soret and Dufour and Hall effects are taken into account. Analysis has been carried out in a wave frame of reference. Expressions for velocity, pressure gradient, temperature and concentration are constructed. Pumping and trapping phenomena are examined. Impact of sundry parameters on the velocity, temperature and concentration is discussed.

  13. Transient magneto-peristaltic flow of couple stress biofluids: a magneto-hydro-dynamical study on digestive transport phenomena.

    Science.gov (United States)

    Tripathi, Dharmendra; Anwar Bég, O

    2013-11-01

    Magnetic fields are increasingly being utilized in endoscopy and gastric transport control. In this regard, the present study investigates the influence of a transverse magnetic field in the transient peristaltic rheological transport. An electrically-conducting couple stress non-Newtonian model is employed to accurately simulate physiological fluids in peristaltic flow through a sinusoidally contracting channel of finite length. This model is designed for computing the intra-bolus oesophageal and intestinal pressures during the movement of food bolus in the digestive system under magneto-hydro-dynamic effects. Long wavelength and low Reynolds number approximations have been employed to reduce the governing equations from nonlinear to linear form, this being a valid approach for creeping flows which characterizes physiological dynamics. Analytical approximate solutions for axial velocity, transverse velocity, pressure gradient, local wall shear stress and volumetric flow rate are obtained for the non-dimensional conservation equations subject to appropriate boundary conditions. The effects of couple stress parameter and transverse magnetic field on the velocity profile, pressure distribution, local wall shear stress and the averaged flow rate are discussed with the aid of computational results. The comparative study of non-integral and integral number of waves propagating along the finite length channel is also presented. Magnetic field and non-Newtonian properties are found to strongly influence peristaltic transport. PMID:23911695

  14. Transient magneto-peristaltic flow of couple stress biofluids: a magneto-hydro-dynamical study on digestive transport phenomena.

    Science.gov (United States)

    Tripathi, Dharmendra; Anwar Bég, O

    2013-11-01

    Magnetic fields are increasingly being utilized in endoscopy and gastric transport control. In this regard, the present study investigates the influence of a transverse magnetic field in the transient peristaltic rheological transport. An electrically-conducting couple stress non-Newtonian model is employed to accurately simulate physiological fluids in peristaltic flow through a sinusoidally contracting channel of finite length. This model is designed for computing the intra-bolus oesophageal and intestinal pressures during the movement of food bolus in the digestive system under magneto-hydro-dynamic effects. Long wavelength and low Reynolds number approximations have been employed to reduce the governing equations from nonlinear to linear form, this being a valid approach for creeping flows which characterizes physiological dynamics. Analytical approximate solutions for axial velocity, transverse velocity, pressure gradient, local wall shear stress and volumetric flow rate are obtained for the non-dimensional conservation equations subject to appropriate boundary conditions. The effects of couple stress parameter and transverse magnetic field on the velocity profile, pressure distribution, local wall shear stress and the averaged flow rate are discussed with the aid of computational results. The comparative study of non-integral and integral number of waves propagating along the finite length channel is also presented. Magnetic field and non-Newtonian properties are found to strongly influence peristaltic transport.

  15. Study of the Behavior of a Bell-Shaped Colonic Self-Expandable NiTi Stent under Peristaltic Movements

    Directory of Open Access Journals (Sweden)

    Sergio Puértolas

    2013-01-01

    Full Text Available Managing bowel obstruction produced by colon cancer requires an emergency intervention to patients usually in poor conditions, and it requires creating an intestinal stoma in most cases. Regardless of that the tumor may be resectable, a two-stage surgery is mandatory. To avoid these disadvantages, endoscopic placement of self-expanding stents has been introduced more than 10 years ago, as an alternative to relieve colonic obstruction. It can be used as a bridge to elective single-stage surgery avoiding a stoma or as a definitive palliative solution in patients with irresectable tumor or poor estimated survival. Stents must be capable of exerting an adequate radial pressure on the stenosed wall, keeping in mind that stent must not move or be crushed, guaranteeing an adequate lumen when affected by peristaltic waves. A finite element simulation of bell-shaped nitinol stent functionality has been done. Catheter introduction, releasing at position, and the effect of peristaltic wave were simulated. To check the reliability of the simulation, a clinical experimentation with porcine specimens was carried out. The stent presented a good deployment and flexibility. Stent behavior was excellent, expanding from the very narrow lumen corresponding to the maximum peristaltic pressure to the complete recovery of operative lumen when the pressure disappears.

  16. Adaptive Q control for Tapping-mode Nano-scanning Using a Piezo-actuated Bimorph Probe

    CERN Document Server

    Gunev, Ihsan; Karaman, Sertac; Basdogan, Cagatay

    2012-01-01

    A new approach, called Adaptive Q-control, for tapping-mode Atomic Force Microscopy (AFM) is introduced and implemented on a home-made AFM set-up utilizing a Laser Doppler Vibrometer (LDV) and a piezo-actuated bimorph probe. In the standard Q-control, the effective Q-factor of the scanning probe is adjusted prior to the scanning depending on the application. However, there is a trade-off in setting the effective Q-factor of an AFM probe. The Q-factor is either increased to reduce the tapping forces or decreased to increase the maximum achievable scan speed. Realizing these two benefits simultaneously using the standard Q-control is not possible. In adaptive Q-control, the Q-factor of the probe is set to an initial value as in standard Q-control, but then modified on the fly during scanning when necessary to achieve this goal. In this paper, we present the basic theory behind the adaptive Q-control, the electronics enabling the on-line modification of the probe's effective Q-factor, and the results of the expe...

  17. A Peristaltic Pump Integrated on a 100% Glass Microchip Using Computer Controlled Piezoelectric Actuators

    Directory of Open Access Journals (Sweden)

    Yo Tanaka

    2014-05-01

    Full Text Available Lab-on-a-chip technology is promising for the miniaturization of chemistry, biochemistry, and/or biology researchers looking to exploit the advantages of a microspace. To manipulate fluid on a microchip, on-chip pumps are indispensable. To date, there have been several types of on-chip pumps including pneumatic, electroactive, and magnetically driven. However these pumps introduce polymers, metals, and/or silicon to the microchip, and these materials have several disadvantages, including chemical or physical instability, or an inherent optical detection limit. To overcome/avoid these issues, glass has been one of the most commonly utilized materials for the production of multi-purpose integrated chemical systems. However, glass is very rigid, and it is difficult to incorporate pumps onto glass microchips. This paper reports the use of a very flexible, ultra-thin glass sheet (minimum thickness of a few micrometers to realize a pump installed on an entirely glass-based microchip. The pump is a peristaltic-type, composed of four serial valves sealing a cavity with two penetrate holes using ultra-thin glass sheet. By this pump, an on-chip circulating flow was demonstrated by directly observing fluid flow, visualized via polystyrene tracking particles. The flow rate was proportional to the pumping frequency, with a maximum flow rate of approximately 0.80 μL/min. This on-chip pump could likely be utilized in a wide range of applications which require the stability of a glass microchip.

  18. Peristaltic transport of a generalized Burgers’ fluid: Application to the movement of chyme in small intestine

    Science.gov (United States)

    Tripathi, Dharmendra; Pandey, S. K.; Das, S.

    2011-07-01

    The present investigation deals with the peristaltic transport of generalized Burgers' fluid with fractional element model in a channel. The analysis is carried out under long wavelength and low Reynolds number assumptions. An efficient mathematical tool, namely, Adomian decomposition method, is used to obtain the analytical approximate solutions of the fractional differential equation. The channel is governed by the propagation of sinusoidal waves that help the walls contract and relax but not expand beyond the natural boundary. The expressions of axial velocity, volume flow rate and pressure gradient are obtained. The effects of the fractional parameters and the material constants are discussed on pressure difference and the friction force across one wavelength. The comparative studies for various models of viscoelastic fluids such as fractional generalized Burgers' model, generalized Burgers' model, fractional Burgers' model and Burgers' model are performed. It is inferred that the movement of viscoelastic chyme with generalized Burgers' model through the small intestine is favorable in comparison to the movement of viscoelastic chyme with fractional generalized Burgers' model.

  19. Motion generation of peristaltic mobile robot with particle swarm optimization algorithm

    Science.gov (United States)

    Homma, Takahiro; Kamamichi, Norihiro

    2015-03-01

    In developments of robots, bio-mimetics is attracting attention, which is a technology for the design of the structure and function inspired from biological system. There are a lot of examples of bio-mimetics in robotics such as legged robots, flapping robots, insect-type robots, fish-type robots. In this study, we focus on the motion of earthworm and aim to develop a peristaltic mobile robot. The earthworm is a slender animal moving in soil. It has a segmented body, and each segment can be shorted and lengthened by muscular actions. It can move forward by traveling expanding motions of each segment backward. By mimicking the structure and motion of the earthworm, we can construct a robot with high locomotive performance against an irregular ground or a narrow space. In this paper, to investigate the motion analytically, a dynamical model is introduced, which consist of a series-connected multi-mass model. Simple periodic patterns which mimic the motions of earthworms are applied in an open-loop fashion, and the moving patterns are verified through numerical simulations. Furthermore, to generate efficient motion of the robot, a particle swarm optimization algorithm, one of the meta-heuristic optimization, is applied. The optimized results are investigated by comparing to simple periodic patterns.

  20. Hall and ion slip effects on peristaltic flow and heat transfer analysis with Ohmic heating

    Institute of Scientific and Technical Information of China (English)

    S ASGHAR; Q HUSSAIN; T HAYAT; F ALSAADI

    2014-01-01

    The peristaltic transport of a magnetohydrodynamic (MHD) fluid is exam-ined for both symmetric and asymmetric channels. Hall and ion slip effects are taken into account. The heat transfer is analyzed by considering the effects of viscous and Ohmic dissipations. The relevant flow problems are first modeled, and then the closed form solutions are constructed under the assumptions of long wavelength and low Reynolds number. The solutions are analyzed through graphical illustration. It is noted that the velocity increases but the temperature decreases with the increases in the Hall and ion slip parameters. The axial pressure gradient is less in magnitude in the presence of Hall and ion slip currents. The Hall and ion slip effects are to decrease the maximum pres-sure against which peristalsis works as a pump. The free pumping flux decreases with the increases in the Hall and ion slip parameters. The increases in the Hall and ion slip parameters result in an increase in the size of the trapped bolus.

  1. 蠕动泵在化学反应过程中的应用%The Peristaltic Pump's Application in the Chemical Reaction Process

    Institute of Scientific and Technical Information of China (English)

    冯雨静; 张晓桂; 高波

    2013-01-01

    为了减轻化学实验人员的劳动强度,提出采用蠕动泵进料。论述了蠕动泵的发展现状,从化学反应过程的应用角度详细阐述了蠕动泵的应用特点和优势,表明蠕动泵在化学反应过程中应用的可行性,简述了蠕动泵软管的应用要求和蠕动泵在应用过程中的控制方法。%In order to reduce the labor intensity of chemical ex-periments,a peristaltic pump feeding method is proposed. This article introduces the peristaltic pump's development status and working principle. Its applying characteristic and advantage in the chemical reaction process are described in details to show the feasibility of the peristaltic pump's application in the chemical reaction process. In addition, this article expounds the application requirements of peristaltic pump hose and the controlling ways and means when applying the peristaltic pump.

  2. 5-HT3 and 5-HT4 antagonists inhibit peristaltic contractions in guinea-pig distal colon by mechanisms independent of endogenous 5-HT

    Directory of Open Access Journals (Sweden)

    Tiong Cheng Sia

    2013-08-01

    Full Text Available Recent studies have shown that endogenous serotonin is not required for colonic peristalsis in vitro, nor gastrointestinal (GI transit in vivo. However, antagonists of 5-Hydroxytryptamine (5-HT receptors can inhibit peristalsis and GI-transit in mammals, including humans. This raises the question of how these antagonists inhibit GI-motility and transit, if depletion of endogenous 5-HT does not cause any significant inhibitory changes to either GI-motility or transit ? We investigated the mechanism by which 5-HT3 and 5-HT4 antagonists inhibit distension-evoked peristaltic contractions in guinea-pig distal colon. In control animals, repetitive peristaltic contractions of the circular muscle were evoked in response to fixed fecal pellet distension. Distension-evoked peristaltic contractions were unaffected in animals with mucosa and submucosal plexus removed, that were also treated with reserpine (to deplete neuronal 5-HT. In control animals, peristaltic contractions were blocked temporarily by ondansetron (1-10µM and SDZ-205-557 (1-10µM in many animals. Interestingly, after this temporary blockade, and whilst in the continued presence of these antagonists, peristaltic contractions recovered, with characteristics no different from controls. Surprisingly, similar effects were seen in mucosa-free preparations, which had no detectable 5-HT, as detected by mass spectrometry. In summary, distension-evoked peristaltic reflex contractions of the circular muscle layer of the guinea-pig colon can be inhibited temporarily, or permanently, in the same preparation by selective 5-HT3 and 5-HT4 antagonists, depending on the concentration of the antagonists applied. These effects also occur in preparations that lack any detectable 5-HT. We suggest caution should be exercised when interpreting the effects of 5-HT3 and 5-HT4 antagonists; and the role of endogenous 5-HT, in the generation of distension-evoked colonic peristalsis.

  3. Peristaltic flow of a couple stress fluid under the effect of induced magnetic field in an asymmetric channel

    Energy Technology Data Exchange (ETDEWEB)

    Nadeem, Sohail; Akram, Safia [Quaid-i-Azam University, Department of Mathematics, Islamabad (Pakistan)

    2011-01-15

    The present paper investigates the peristaltic transport of a couple stress fluid in an asymmetric channel with the effect of the induced magnetic field. The exact solutions of momentum and the magnetic field equations have been calculated under the assumptions of long wave length and low but finite Reynolds number. The expression for pressure rise has been computed numerically using mathematics software Mathematica. The graphical results have been presented to discuss the physical behavior of various physical parameters of interest. Finally, the trapping phenomena have been discussed for various physical parameters. (orig.)

  4. Convective heat and mass transfer on MHD peristaltic flow of Williamson fluid with the effect of inclined magnetic field

    Science.gov (United States)

    Veera Krishna, M.; Swarnalathamma, B. V.

    2016-05-01

    In this paper, we discussed the peristaltic MHD flow of an incompressible and electrically conducting Williamson fluid in a symmetric planar channel with heat and mass transfer under the effect of inclined magnetic field. Viscous dissipation and Joule heating are also taken into consideration. Mathematical model is presented by using the long wavelength and low Reynolds number approximations. The differential equations governing the flow are highly nonlinear and thus perturbation solution for small Weissenberg number (We Effects of the heat and mass transfer on the longitudinal velocity, temperature and concentration are studied in detail. Main observations are presented in the concluding section. The streamlines pattern is also given due attention.

  5. Effect of an inclined magnetic field on peristaltic flow of Williamson fluid in an inclined channel with convective conditions

    Science.gov (United States)

    Hayat, T.; Bibi, Shahida; Rafiq, M.; Alsaedi, A.; Abbasi, F. M.

    2016-03-01

    This paper deals with the influence of inclined magnetic field on peristaltic flow of an incompressible Williamson fluid in an inclined channel with heat and mass transfer. Convective conditions of heat and mass transfer are employed. Viscous dissipation and Joule heating are taken into consideration. Mathematical modeling also includes Soret and Dufour effects. Channel walls have compliant properties. Analysis has been carried out through long wavelength and low Reynolds number approach. Resulting problems are solved for small Weissenberg number. Impacts of variables reflecting the salient features of wall properties, Biot numbers and Soret and Dufour on the velocity, temperature, concentration and heat transfer coefficient are pointed out. Trapping phenomenon is also analyzed.

  6. Numerical Analysis for Peristaltic Motion of MHD Eyring-Prandtl Fluid in an Inclined Symmetric Cannel with Inclined Magnetic Field

    Directory of Open Access Journals (Sweden)

    Fahad Abbasi

    2016-01-01

    Full Text Available This article addresses the peristaltic transport of Eyring-Prandtl fluid in an inclined asymmetric channel. Heat and mass transfer phenomena along with Soret and Dufour effects is analyzed. Effects of inclined magnetic field and Joule heating are also discussed. Long wavelength approximation is adopted. Numerical computations for flow quantities of interest are analyzed. It is found that the parabolic velocity profile tends to shift from center of the channel towards the channel walls in the case of opposing flow. Velocity and temperature decrease whereas concentration increases by increasing the non-Newtonian parameter. Further the dependence of magnetic field on the angle is quite significant

  7. Analytical Analysis of Peristaltic Flow of a Six Constant Jeffreys Model of Fluid in an Inclined Planar Channel

    Directory of Open Access Journals (Sweden)

    Safia AKRAM

    2013-01-01

    Full Text Available In this paper we have investigated the peristaltic flow of an incompressible six constant Jeffreys model of fluid in an asymmetric channel. The flow is investigated in a wave frame of reference moving with the velocity of the wave. We have modeled the governing equations of a two dimensional six constant Jeffreys model of fluid under long wave length and low Reynolds number approximation. The analytical and numerical solutions of the proposed problem are discussed. The expression for the pressure rise is calculated using numerical integration. The Graphical results are presented to interpret various physical parameters of interest.

  8. Peristaltic Transport of a Physiological Fluid in an Asymmetric Porous Channel in the Presence of an External Magnetic Field

    CERN Document Server

    Misra, J C; Shit, G C; 10.1142/S0219519408002784

    2010-01-01

    The paper deals with a theoretical investigation of the peristaltic transport of a physiological fluid in a porous asymmetric channel under the action of a magnetic field. The stream function, pressure gradient and axial velocity are studied by using appropriate analytical and numerical techniques. Effects of different physical parameters such as permeability, phase difference, wave amplitude and magnetic parameter on the velocity, pumping characteristics, streamline pattern and trapping are investigated with particular emphasis. The computational results are presented in graphical form. The results are found to be in perfect agreement with those of a previous study carried out for a non-porous channel in the absence of a magnetic field.

  9. Mixed convective heat and mass transfer analysis for peristaltic transport in an asymmetric channel with Soret and Dufour effects

    Institute of Scientific and Technical Information of China (English)

    F M Abbasi; A Alsaedi; T Hayat

    2014-01-01

    The present investigation addresses the simultaneous effects of heat and mass transfer in the mixed convection peristaltic flow of viscous fluid in an asymmetric channel. The channel walls exhibit the convective boundary conditions. In addition, the effects due to Soret and Dufour are taken into consideration. Resulting problems are solved for the series solutions. Numerical values of heat and mass transfer rates are displayed and studied. Results indicate that the concentration and temperature of the fluid increase whereas the mass transfer rate at the wall decreases with increase of the mass transfer Biot number. Furthermore, it is observed that the temperature decreases with the increase of the heat transfer Biot number.

  10. Combined effect of couple stresses and heat and mass transfer on peristaltic flow with slip conditions in a tube.

    Science.gov (United States)

    Sobh, Ayman M

    2013-10-01

    In this article, the influence of heat and mass transfer on peristaltic transport of a couple stress fluid in a uniform tube with slip conditions on the wall is studied. The problem can model the blood flow in living creatures. Under long wavelength approximation and zero Reynolds number, exact solutions for the axial velocity component, pressure gradient, and both temperature and concentration fields are derived. The pressure rise is computed numerically and explained graphically. Moreover, effects of various physical parameters of the problem on temperature distribution, concentration field, and trapping are studied and discussed graphically.

  11. DYNAMIC BIMORPH THERMO-PIEZOELECTRIC BENDERS WITH ARBITRARY SUPPORT LOCATION. PART II: APPLICATION TO ENERGY HARVESTING-NUMERICAL RESULTS AND DISCUSSIONS

    Directory of Open Access Journals (Sweden)

    Bagdasaryan, Gevorg Y.

    2016-06-01

    Full Text Available A comprehensive theoretical analysis of a dynamic thermo-ferro-electric pre-stressed bimorph energy harvester is performed. The analysis also takes into account pyroelectric and thermal expansion effects. The most general analytical expression for the energy conversation coefficients are presented for bi-layer. These coefficients we derive for more general situation when mechanical, electrical, thermal fields are present. We derive coefficients (transformation coefficients for sensing, actuating, and energy harvesting. As a particular case, we derive an analytical expression for the energy harvesting coefficient due to pyroelectric and thermal expansion effects in a rater general situation. This is a function of material properties, location of boundary conditions, vibration frequency, and in plane compressive/tensile follower force. Numerical simulations of the analytical results are presented. Effects of volume fraction, material properties, applied mechanical loads, and boundary conditions on the harvesting coefficients are introduced in the figures. The results for a cantilever and a simply-supported plate-layer are obtained as particular cases. The result for a low frequency (static system is obtained as a particular case by approaching the vibration frequency to zero. It is shown that volume fraction, material properties, plain compressive/tensile follower force, the location of the boundary conditions, and the vibrational frequency of the bimorph strongly influence the strain distribution, and this in effect influences the charge coefficient and the generation of energy. The proposed model can be extended to thermal energy harvesters of piezoelectric-shape memory alloy (SMA composites.

  12. Pre-stressed piezoelectric bimorph micro-actuators based on machined 40 µm PZT thick films: batch scale fabrication and integration with MEMS

    International Nuclear Information System (INIS)

    The projected force–displacement capability of piezoelectric ceramic films in the 20–50 µm thickness range suggests that they are well suited to many micro-fluidic and micro-pneumatic applications. Furthermore when they are configured as bending actuators and operated at ∼ 1 V µm−1 they do not necessarily conform to the high-voltage, very low-displacement piezoelectric stereotype. Even so they are rarely found today in commercial micro-electromechanical devices, such as micro-pumps and micro-valves, and the main barriers to making them much more widely available would appear to be processing incompatibilities rather than commercial desirability. In particular, the issues associated with integration of these devices into MEMS at the production level are highly significant and they have perhaps received less attention in the mainstream than they deserve. This paper describes a fabrication route based on ultra-precision ceramic machining and full-wafer bonding for cost-effective batch scale production of thick film PZT bimorph micro-actuators and their integration with MEMS. The resulting actuators are pre-stressed (ceramic in compression) which gives them added performance, they are true bimorphs with bi-directional capability and they exhibit full bulk piezoelectric ceramic properties. The devices are designed to integrate with ancillary systems components using transfer-bonding techniques. The work forms part of the European Framework 6 Project 'Q2M—Quality to Micro'

  13. 压电双晶片扫描器的低温迟滞蠕变特性%Cryogenic hysteresis and creep characteristics of piezoelectric bimorph scanner

    Institute of Scientific and Technical Information of China (English)

    张旋; 潘鸣

    2012-01-01

    The cryogenic hysteresis and creep characteristics of piezoelectric bimorph scanners for cryogenic optical systems in space infrared cameras were studied. The piezoelectric bimorph has superior characteristics of large displacement, high resolution, no self-heating, etc. , moreover, it can work efficiently at a cryogenic temperature. However,the inherent hysteresis and creep characteristics of the piezoelectric bmorph have a large impact on the scanning accuracy when it is used for high precision scanning. In this paper, the hysteresis and creep characteristics of a fabricated piezoelectric bimorph scanner were experimentally studied at room temperature and cryogenic temperature and the results were compared. The results indicate that both hysteresis displacement and creep displacement of the piezoelectric bimorph scanner have a large decrease, but the decrease of total travel displacement is much larger, which leads the hysteresis rate and creep coefficient increase more large. The hysteresis rate at 120 K is twice that at 300 K and the creep coefficient at 120 K increases by an order of magnitude as compared with that at 300 K. Results mean that the hysteresis and creep characteristics of piezoelectric bimorph scanner at cryogenic temperature are more serious than it at room temperature, which will bring greater impact when it is used for high precision applications.%研究了用于空间红外相机低温光学系统的压电双晶片扫描器的低温迟滞蠕变问题.压电双晶片具有行程大,不发热,在低温下仍然能够工作等优点,然而由于压电陶瓷固有的迟滞蠕变特性,使得其扫描精度受到了较大的影响.本文在常温和低温下,对所研制的压电双晶片扫描器的迟滞和蠕变特性进行实验研究和特性对比.结果显示:尽管压电双晶片扫描器的迟滞量和蠕变量均有大幅度下降,但由于总行程的下降幅度更大,使得迟滞度和蠕变系数有较大上升;120 K

  14. Detection of Crohn's disease: Comparison of CT and MR enterography without anti-peristaltic agents performed on the same day

    International Nuclear Information System (INIS)

    Objective: To directly compare CT enterography (CTE) and MR enterography (MRE) without antiperistaltic agents. Materials/methods: 26 patients referred for CTE underwent CTE immediately followed by MRE without use of an anti-peristaltic agent. Each study was evaluated on a 10 point scale for exam quality, level of diagnostic confidence, and presence of Crohn's disease. Kappa analysis was performed to determine the degree of agreement between the CTE and MRE of each patient. Results: 25 patients completed the MRE. The quality of the CTEs was judged as excellent by both readers (reader 1 = average 9.5/10, reader 2 = average 9.1/10). The quality of the MREs was ranked lower than the CTEs by both readers (reader 1 = average 8.9/10, reader 2 = average 7.2/10), which was statistically significant (p < 0.05). The level of confidence in interpretation was not significantly different between CTE and MRE for reader 1 or 2 (p = 0.3). There was substantial agreement between readers for the presence or absence of Crohn's disease on both CTE (kappa = 0.75) and MRE (kappa = 0.67). Conclusion: MR enterography without anti-peristaltic agents results in high diagnostic confidence and excellent agreement for the presence of Crohn's disease.

  15. Effect of radiation and magnetic field on peristaltic transport of nanofluids through a porous space in a tapered asymmetric channel

    Energy Technology Data Exchange (ETDEWEB)

    Kothandapani, M., E-mail: mkothandapani@gmail.com [Department of Mathematics, University College of Engineering Arni, (A Constituent College of Anna University Chennai), Arni 632326, Tamil Nadu (India); Prakash, J., E-mail: prakashjayavel@yahoo.co.in [Department of Mathematics, Arulmigu Meenakshi Amman College of Engineering, Vadamavandal 604410, Tamil Nadu (India)

    2015-03-15

    Theoretical analyses on the effect of radiation and MHD on the peristaltic flow of a nanofluid through a porous medium in a two dimensional tapered asymmetric channel has been made. The nanofluid is assumed to be electrically conducting in the presence of a uniform magnetic field. The transport equation accounts the both Brownian motion and thermophoresis along with the radiation reaction. The problem has been further simplified with the authentic assumptions of long wavelength and small Reynolds number. The analytical expressions obtained for the axial velocity, stream function, temperature field, nanoparticle fraction field and pressure gradient provide satisfactory explanation. Influence of various parameters on the flow characteristics have been discussed with the help of graphical results. The trapping phenomenon has also been discussed in detail. - Highlights: • Combine effect of thermal radiation and MHD on the peristaltic flow of a Newtonian nanofluid are discussed. • This work may be first attempt dealing the study of Newtonian nanofluid flow in the porous tapered asymmetric channel. • The velocity, stream function, temperature field and nanoparticle fraction field provide satisfactory explanation with help of graphs.

  16. Peristaltic hemodynamic flow of couple stress fluid through a porous medium under the influence of magnetic field with slip effect

    Science.gov (United States)

    Swarnalathamma, B. V.; Krishna, M. Veera

    2016-05-01

    In this paper, we discussed the theoretical and computational study of peristaltic hemodynamic flow of couple stress fluids through a porous medium under the influence of magnetic field with wall slip condition. Actually this study is motivated towards the physiological flow of the blood in the micro circulatory system by taking account of the particle size effect. We consider the Reynolds number is small enough and the wave length to diameter ratio is large enough to negate inertial effects. The governing equations for the couple stress fluid flow through porous medium based on stoke constitutive equations and Brinkman model. The exact solutions for axial velocity, pressure gradient, frictional force, stream function and mechanical efficiency are obtained analytically, its behaviour computationally discussed with reference to different physical parameters reflecting couple stress parameter, Hartmann number, permeability parameter, slip parameter as well as amplitude ratio on pumping characteristics and frictional force, stream lines pattern and trapping of peristaltic flow pattern are studied with particular emphasis making use of graphs.

  17. Peristaltic transport of MHD Williamson fluid in an inclined asymmetric channel through porous medium with heat transfer

    Institute of Scientific and Technical Information of China (English)

    K. Ramesh; M. Devakar

    2015-01-01

    The intention of this investigation is to study the effects of heat transfer and inclined magnetic field on the peristaltic flow of Williamson fluid in an asymmetric channel through porous medium. The governing two-dimensional equations are simplified under the assumption of long wavelength approximation. The simplified equations are solved for the stream function, temperature, and axial pressure gradient by using a regular perturbation method. The expression for pressure rise is computed numerically. The profiles of velocity, pressure gradient, temperature, heat transfer coefficient and stream function are sketched and interpreted for various embedded parameters and also the behavior of stream function for various wave forms is discussed through graphs. It is observed that the peristaltic velocity increases from porous medium to non-porous medium, the magnetic effects have increasing effect on the temperature, and the size of the trapped bolus decreases with the increasing of magnetic effects while the trend is reversed with the increasing of Darcy number. Moreover, limiting solutions of our problem are in close agreement with the corresponding results of the Newtonian fluid model.

  18. Numerical simulation of peristaltic flow of a biorheological fluid with shear-dependent viscosity in a curved channel.

    Science.gov (United States)

    Ali, N; Javid, K; Sajid, M; Anwar Bég, O

    2016-01-01

    Peristaltic motion of a non-Newtonian Carreau fluid is analyzed in a curved channel under the long wavelength and low Reynolds number assumptions, as a simulation of digestive transport. The flow regime is shown to be governed by a dimensionless fourth-order, nonlinear, ordinary differential equation subject to no-slip wall boundary conditions. A well-tested finite difference method based on an iterative scheme is employed for the solution of the boundary value problem. The important phenomena of pumping and trapping associated with the peristaltic motion are investigated for various values of rheological parameters of Carreau fluid and curvature of the channel. An increase in Weissenberg number is found to generate a small eddy in the vicinity of the lower wall of the channel, which is enhanced with further increase in Weissenberg number. For shear-thinning bio-fluids (power-law rheological index, n Weissenberg number displaces the maximum velocity toward the upper wall. For shear-thickening bio-fluids, the velocity amplitude is enhanced markedly with increasing Weissenberg number.

  19. A computer-controlled system to simulate conditions of the large intestine with peristaltic mixing, water absorption and absorption of fermentation products

    NARCIS (Netherlands)

    Minekus, M.; Smeets-Peeters, M.; Havenaar, R.; Bernalier, A.; Fonty, G.; Marol-Bonnin, S.; Alric, M.; Marteau, P.; Huis Veld, J.H.J. in 't

    1999-01-01

    This paper introduces a new type of system to simulate conditions in the large intestine. This system combines removal of metabolites and water with peristaltic mixing to obtain and handle physiological concentrations of microorganisms, dry matter and microbial metabolites. The system has been desig

  20. 同步辐射中双压电片反射镜的研究现状∗%Present research status of piezo electric bimorph mirrors in synchrotron radiation sources

    Institute of Scientific and Technical Information of China (English)

    张瑶; 汤善治; 李明; 王立超; 高俊祥

    2016-01-01

    The third-generation synchrotron radiation sources are widely used in physics, chemistry, material science, etc. due to their light beams with high brilliance and low emittance. In order to efficiently utilize such light beams for scientific research, reflective mirrors with excellent figure quality are required. The reflective mirrors on the beamlines of synchrotron radiation sources consist of fixed polished shape mirrors and bendable mirrors. Bendable mirrors have been attracting the attention of the synchrotron radiation community because their curvatures can be varied to realize different focusing properties. Classical bendable mirrors are realized by applying mechanical moment at the ends of the mirror substrates. In this paper, we introduce a new concept of bendable mirrors, X-ray adaptive mirrors which are based on the adaptive optics technology and the properties of piezoelectric bimorph systems. X-ray adaptive mirrors exhibit many advantages over the classical bendable mirrors, such as mechanics-free, figure local corrections, and good focusing properties. The piezoelectric bimorph mirrors have been used in astronomy to correct the wavefront distortions introduced by atmospheric turbulence in real time. The piezoelectric bimorph mirror was first introduced into the field of synchrotron radiation by European Synchrotron Radiation Facility (ESRF) in the 1990s for making an X-ray reflective mirror. Compared with astronomy community, synchrotron radiation community is not interested in high-speed wavefront correction, but looking for the ultimate precision of the surface shape of piezoelectric bimorph mirror. In the second part of this paper, the usual structure and working principle are briefly described. Piezoelectric bimorph mirrors are laminated structures consisting of two strips of an active material such as zirconate lead titanate (PZT) and two faceplates of a reflecting material such as silicon. A discrete or continuous control electrode is located

  1. Numerical Modeling and Experimental Validation by Calorimetric Detection of Energetic Materials Using Thermal Bimorph Microcantilever Array: A Case Study on Sensing Vapors of Volatile Organic Compounds (VOCs).

    Science.gov (United States)

    Kang, Seok-Won; Fragala, Joe; Banerjee, Debjyoti

    2015-01-01

    Bi-layer (Au-Si₃N₄) microcantilevers fabricated in an array were used to detect vapors of energetic materials such as explosives under ambient conditions. The changes in the bending response of each thermal bimorph (i.e., microcantilever) with changes in actuation currents were experimentally monitored by measuring the angle of the reflected ray from a laser source used to illuminate the gold nanocoating on the surface of silicon nitride microcantilevers in the absence and presence of a designated combustible species. Experiments were performed to determine the signature response of this nano-calorimeter platform for each explosive material considered for this study. Numerical modeling was performed to predict the bending response of the microcantilevers for various explosive materials, species concentrations, and actuation currents. The experimental validation of the numerical predictions demonstrated that in the presence of different explosive or combustible materials, the microcantilevers exhibited unique trends in their bending responses with increasing values of the actuation current. PMID:26334276

  2. The Influence of a Micropolar Fluid on Peristaltic Transport in an Annulus: Application of the Clot Model

    Directory of Open Access Journals (Sweden)

    Kh. S. Mekheimer

    2008-01-01

    Full Text Available A serious pathological condition is encountered when some blood constituents deposited on the blood vessels get detached from the wall, join the blood stream again and form a clot. Study of the peristaltic transport of a micropolar fluid in an annular region is investigated under low Reynolds number and long wavelength approximations. We model a small artery as a tube having a sinusoidal wave travelling down its wall and a clot model inside it. Closed form solutions are obtained for the velocity and the microrotation components, as well as the stream function, and they contain new additional parameters, namely, δ, the height of the clot, N, the coupling number and m, the micropolar parameter. The pressure rise and friction force on the inner and the outer tubes have been discussed for various values of the physical parameters of interest.

  3. Numerical analysis for MHD peristaltic transport of Carreau-Yasuda fluid in a curved channel with Hall effects

    Science.gov (United States)

    Abbasi, F. M.; Hayat, T.; Alsaedi, A.

    2015-05-01

    Impact of applied magnetic field on the peristaltic transport of Carreau-Yasuda fluid in a curved conduit is analyzed in this article. Hall effects are also taken into consideration. Lubrication approach is utilized in problem formulation. Resulting nonlinear system is solved numerically. Results for axial velocity, pressure gradient, pressure rise per wavelength and stream function are obtained and studied graphically. Results revealed that for small values of curvature parameter the fluid velocity is not symmetric about the centerline. Also increase in the value of Hall parameter balances the magnetic influence of applied magnetic field by some extent. Further, the Carreau-Yasuda fluid possesses large size of trapped bolus when compared with the Newtonian fluid.

  4. Numerical analysis for MHD peristaltic transport of Carreau–Yasuda fluid in a curved channel with Hall effects

    Energy Technology Data Exchange (ETDEWEB)

    Abbasi, F.M., E-mail: abbasisarkar@gmail.com [Department of Mathematics, Comsats Institute of Information Technology, Islamabad 44000 (Pakistan); Hayat, T. [Department of Mathematics, Quaid-I-Azam University, 45320 Islamabad 44000 (Pakistan); Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Alsaedi, A. [Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

    2015-05-15

    Impact of applied magnetic field on the peristaltic transport of Carreau–Yasuda fluid in a curved conduit is analyzed in this article. Hall effects are also taken into consideration. Lubrication approach is utilized in problem formulation. Resulting nonlinear system is solved numerically. Results for axial velocity, pressure gradient, pressure rise per wavelength and stream function are obtained and studied graphically. Results revealed that for small values of curvature parameter the fluid velocity is not symmetric about the centerline. Also increase in the value of Hall parameter balances the magnetic influence of applied magnetic field by some extent. Further, the Carreau–Yasuda fluid possesses large size of trapped bolus when compared with the Newtonian fluid.

  5. Influences of rotation and thermophoresis on MHD peristaltic transport of Jeffrey fluid with convective conditions and wall properties

    Science.gov (United States)

    Hayat, T.; Rafiq, M.; Ahmad, B.

    2016-07-01

    This article aims to predict the effects of convective condition and particle deposition on peristaltic transport of Jeffrey fluid in a channel. The whole system is in a rotating frame of reference. The walls of channel are taken flexible. The fluid is electrically conducting in the presence of uniform magnetic field. Non-uniform heat source/sink parameter is also considered. Mass transfer with chemical reaction is considered. Relevant equations for the problems under consideration are first modeled and then simplified using lubrication approach. Resulting equations for stream function and temperature are solved exactly whereas mass transfer equation is solved numerically. Impacts of various involved parameters appearing in the solutions are carefully analyzed.

  6. Influence of Magnetic Field on the Peristaltic Flow of a Viscous Fluid through a Finite-Length Cylindrical Tube

    Directory of Open Access Journals (Sweden)

    S. K. Pandey

    2010-01-01

    Full Text Available The paper presents an analytical investigation of the peristaltic transport of a viscous fluid under the influence of a magnetic field through a tube of finite length in a dimensionless form. The expressions of pressure gradient, volume flow rate, average volume flow rate and local wall shear stress have been obtained. The effects of the transverse magnetic field and electrical conductivity (i.e. the Hartmann number on the mechanical efficiency of a peristaltic pump have also been studied. The reflux phenomenon is also investigated. It is concluded, on the basis of the pressure distribution along the tubular length and pumping efficiency, that if the transverse magnetic field and the electric conductivity increase, the pumping machinery exerts more pressure for pushing the fluid forward. There is a linear relation between the averaged flow rate and the pressure applied across one wavelength that can restrain the flow due to peristalsis. It is found that there is a particular value of the averaged flow rate corresponding to a particular pressure that does not depend on the Hartmann number. Naming these values ‘critical values’, it is concluded that the pressure required for checking the flow increases with the Hartmann number above the critical value and decreases with it below the critical value. It is also inferred that magneto-hydrodynamic parameters make the fluid more prone to flow reversal. The conclusion applied to oesophageal swallowing reveals that normal water is easier to swallow than saline water. The latter is more prone to flow reversal. A significant difference between the propagation of the integral and non-integral number of waves along the tube is that pressure peaks are identical in the former and different in the latter cases.

  7. Effects of heat and mass transfer on peristaltic flow of a Bingham fluid in the presence of inclined magnetic field and channel with different wave forms

    Energy Technology Data Exchange (ETDEWEB)

    Akram, Safia, E-mail: safia_akram@yahoo.com [Department of Basic Sciences, MCS, National University of Sciences and Technology, Rawalpindi 46000 (Pakistan); Nadeem, S.; Hussain, Anwar [Department of Mathematics, Quaid-i-Azam University, Islamabad 45320 (Pakistan)

    2014-08-01

    In the present analysis we discussed the influence of heat and mass transfer on the peristaltic flow of a Bingham in an inclined magnetic field and channel with different wave forms. The governing two dimensional equations of momentum, heat and mass transfer are simplified under the assumptions of long wavelength and low Reynolds number approximation. The exact solutions of momentum, heat and mass transfer are calculated. Finally, graphical behaviors of various physical parameters are also discussed through the graphical behavior of pressure rise, pressure gradient, temperature concentration and stream functions. - Highlights: • Combine effects of heat and mass transfer on peristaltic flow problem is discussed. • Effects of inclined magnetic field and channel on new fluid model are discussed. • Effects of different wave forms are also discussed in the present flow problem.

  8. Peristaltic Motion of Non-Newtonian Fluid with Heat and Mass Transfer through a Porous Medium in Channel under Uniform Magnetic Field

    OpenAIRE

    Eldabe, Nabil T. M.; Bothaina M. Agoor; Heba Alame

    2014-01-01

    This paper is devoted to the study of the peristaltic motion of non-Newtonian fluid with heat and mass transfer through a porous medium in the channel under the effect of magnetic field. A modified Casson non-Newtonian constitutive model is employed for the transport fluid. A perturbation series’ method of solution of the stream function is discussed. The effects of various parameters of interest such as the magnetic parameter, Casson parameter, and permeability parameter on the velocity, pre...

  9. Numerical solutions of peristaltic flow of a Newtonian fluid under the effects of magnetic field and heat transfer in a porous concentric tubes

    Energy Technology Data Exchange (ETDEWEB)

    Nadeem, Sohail; Akbar, Noreen Sher; Malik, Muhammad Yousaf [Dept. of Mathematics, Quaid-i-Azam Univ., Islamabad (Pakistan)

    2010-05-15

    In the present article, we have studied the effects of heat transfer on a peristaltic flow of a magnetohydrodynamic (MHD) Newtonian fluid in a porous concentric horizontal tube (an application of an endoscope). The problem under consideration is formulated under the assumptions of long wave-length and neglecting the wave number. A closed form of Adomian solutions and numerical solutions are presented which show a complete agreement with each other. The influence of pertinent parameters is analyzed through graphs. (orig.)

  10. Activation of the umami taste receptor (T1R1/T1R3) initiates the peristaltic reflex and pellet propulsion in the distal colon

    OpenAIRE

    Kendig, Derek M; Hurst, Norman R.; Bradley, Zachary L.; Mahavadi, Sunila; Kuemmerle, John F.; Lyall, Vijay; DeSimone, John; Murthy, Karnam S.; John R Grider

    2014-01-01

    Intraluminal nutrients in the gut affect the peristaltic reflex, although the mechanism is not well defined. Recent evidence supports the presence of taste receptors and their signaling components in enteroendocrine cells, although their function is unclear. This study aimed to determine if nutrients modify colonic motility through activation of taste receptors. Colonic sections were immunostained for the umami taste receptor T1R1/T1R3, which mediates the response to umami ligands, such as mo...

  11. Numerical Modeling and Experimental Validation by Calorimetric Detection of Energetic Materials Using Thermal Bimorph Microcantilever Array: A Case Study on Sensing Vapors of Volatile Organic Compounds (VOCs

    Directory of Open Access Journals (Sweden)

    Seok-Won Kang

    2015-08-01

    Full Text Available Bi-layer (Au-Si3N4 microcantilevers fabricated in an array were used to detect vapors of energetic materials such as explosives under ambient conditions. The changes in the bending response of each thermal bimorph (i.e., microcantilever with changes in actuation currents were experimentally monitored by measuring the angle of the reflected ray from a laser source used to illuminate the gold nanocoating on the surface of silicon nitride microcantilevers in the absence and presence of a designated combustible species. Experiments were performed to determine the signature response of this nano-calorimeter platform for each explosive material considered for this study. Numerical modeling was performed to predict the bending response of the microcantilevers for various explosive materials, species concentrations, and actuation currents. The experimental validation of the numerical predictions demonstrated that in the presence of different explosive or combustible materials, the microcantilevers exhibited unique trends in their bending responses with increasing values of the actuation current.

  12. Optimization design for magneto electric coupling prop erty of the magnet/bimorph comp osite%磁铁/压电双晶片复合材料磁电耦合性能的优化设计∗

    Institute of Scientific and Technical Information of China (English)

    张源; 高雁军; 胡诚; 谭兴毅; 邱达; 张婷婷; 朱永丹; 李美亚

    2016-01-01

    Magnetoelectric (ME) composite as one kind of ME material that can yield a strong coupling effect between magnetic and electric fields at room temperature, has drawn widespread attention for decades due to its rich physics contents and significant technological prospect. Except for traditional magnetostrictive/piezoelectric based ME composites, other ME composites have been reported, among which the magnet/piezo-cantilever composites show super strong ME coupling effect. The magnet/piezo-cantilever composite is generally composed of a piezoelectric cantilever and magnets attached at the free end of the cantilever, which realizes ME coupling by force moment-mediated magnetic torque effect and piezoelectric effect. Recently, various configurations of the magnet/piezo-cantilever composites for obtaining higher ME coupling coefficients have been proposed and demonstrated experimentally. However, few theoretical researches of these magnet/piezo-cantilever composites of different configurations have been carried out, which is of great importance for optimizing the design of ME coupling property of the magnet/piezo-cantilever composites. Here in this paper, a theoretical expression for the low-frequency ME coupling coefficient in the magnet/piezo-cantilever composite is deduced based on piezoelectric constitutive equations by using the theory of elastic mechanics. The typical magnet/bimorph composite is chosen as the theoretical model. Based on the deduced theoretical expression, the dependences of the low-frequency ME coupling coefficients in the magnet/bimorph composite on material and structural parameters are numerically calculated. The results show that there are optimal thickness values of the piezoelectric layers in the magnet/bimorph composite with different metal thickness values and material constituents for achieving maximal low-frequency ME coupling coefficients. The thicker the metal layer in the magnet/bimorph composite, the less insensitive the low

  13. Effects of Slip Condition, Variable Viscosity and Inclined Magnetic Field on the Peristaltic Motion of a Non-Newtonian Fluid in an Inclined Asymmetric Channel

    Directory of Open Access Journals (Sweden)

    A. Afsar Khan

    2016-01-01

    Full Text Available The peristaltic motion of a third order fluid due to asymmetric waves propagating on the sidewalls of a inclined asymmetric channel is discussed. The key features of the problem includes longwavelength and low-Reynolds number assumptions. A mathematical analysis has been carried out to investigate the effect of slip condition, variable viscosity and magnetohydrodynamics (MHD. Followed by the nondimensionalization of the nonlinear governing equations along with the nonlinear boundary conditions, a perturbation analysis is made. For the validity of the approximate solution, a numerical solution is obtained using the iterative collocation technique.

  14. Peristaltic Motion of Non-Newtonian Fluid with Heat and Mass Transfer through a Porous Medium in Channel under Uniform Magnetic Field

    Directory of Open Access Journals (Sweden)

    Nabil T. M. Eldabe

    2014-01-01

    Full Text Available This paper is devoted to the study of the peristaltic motion of non-Newtonian fluid with heat and mass transfer through a porous medium in the channel under the effect of magnetic field. A modified Casson non-Newtonian constitutive model is employed for the transport fluid. A perturbation series’ method of solution of the stream function is discussed. The effects of various parameters of interest such as the magnetic parameter, Casson parameter, and permeability parameter on the velocity, pressure rise, temperature, and concentration are discussed and illustrated graphically through a set of figures.

  15. Hall and radial magnetic field effects on radiative peristaltic flow of Carreau-Yasuda fluid in a channel with convective heat and mass transfer

    Science.gov (United States)

    Hayat, T.; Farooq, S.; Alsaedi, A.; Ahmad, B.

    2016-08-01

    The purpose of present investigation is to study the Hall and MHD effects on peristaltic flow of Carreau-Yasuda fluid in a convectively curved configuration. Thermal radiation, Soret and Dufour effects are also accounted. The channel walls comprised the no slip and compliant properties. Constitutive equations for mass, momentum, energy and concentration are first modeled in view of considered assumptions and then simplified under long wavelength and low Reynolds number approximation. Solution of the resulting system of equations is carried out via a regular perturbation technique. Physical behaviors of velocity, temperature, concentration and streamlines are discussed with the help of graphical representation.

  16. Simultaneous effects of radial magnetic field and wall properties on peristaltic flow of Carreau-Yasuda fluid in curved flow configuration

    Directory of Open Access Journals (Sweden)

    T. Hayat

    2015-12-01

    Full Text Available The objective of present article is to address the magnetohydrodynamic (MHD peristaltic flow of Carreau-Yasuda fluid in a curved geometry. The channel boundaries satisfy wall slip and compliant properties. The fluid is electrically conducting through an applied magnetic field in the radial direction. Heat transfer is also studied. Governing equation comprised the viscous dissipation effects. The non-linear expressions are first obtained and then approximated using long wavelength and low Reynolds number considerations. The resulting systems are solved for the series solutions. The expressions of velocity, temperature, heat transfer coefficient and stream function are obtained and analyzed via graphical illustrations.

  17. Effects of Heat and Mass Transfer on MHD Peristaltic Flow of a Non-Newtonian Fluid through a Porous Medium between Two Coaxial Cylinders

    Directory of Open Access Journals (Sweden)

    Abeer A. Shaaban

    2013-01-01

    Full Text Available We investigated the influence of heat and mass transfer on the peristaltic flow of magnetohydrodynamic Eyring-Powell fluid under low Reynolds number and long-wavelength approximation. The fluid flows between two infinite cylinders; the inner tube is uniform, rigid, and rest, while the outer flexible tube has a sinusoidal wave traveling down its wall. The governing equations are solved numerically using finite-difference technique. The velocity, temperature, and concentration distribution are obtained. The features of flow characteristics are analyzed by plotting graphs and discussed in detail.

  18. Simultaneous effects of radial magnetic field and wall properties on peristaltic flow of Carreau-Yasuda fluid in curved flow configuration

    Science.gov (United States)

    Hayat, T.; Tanveer, A.; Alsaadi, F.

    2015-12-01

    The objective of present article is to address the magnetohydrodynamic (MHD) peristaltic flow of Carreau-Yasuda fluid in a curved geometry. The channel boundaries satisfy wall slip and compliant properties. The fluid is electrically conducting through an applied magnetic field in the radial direction. Heat transfer is also studied. Governing equation comprised the viscous dissipation effects. The non-linear expressions are first obtained and then approximated using long wavelength and low Reynolds number considerations. The resulting systems are solved for the series solutions. The expressions of velocity, temperature, heat transfer coefficient and stream function are obtained and analyzed via graphical illustrations.

  19. Influence of induced magnetic field and heat transfer on the peristaltic motion of a Jeffrey fluid in an asymmetric channel: Closed form solutions

    Energy Technology Data Exchange (ETDEWEB)

    Akram, Safia, E-mail: safia_akram@yahoo.com [Department of Humanities and Basic Sciences, Military College of Signals, National University of Sciences and Technology, Rawalpindi 46000 (Pakistan); Department of Mathematics, Quaid-i-Azam University 45320, Islamabad 44000 (Pakistan); Nadeem, S. [Department of Mathematics, Quaid-i-Azam University 45320, Islamabad 44000 (Pakistan)

    2013-02-15

    We discuss the peristaltic motion of a two dimensional Jeffrey fluid in an asymmetric channel under the effects of induced magnetic field and heat transfer. The problem is simplified by using long wave length and low Reynolds approximations. Exact and closed form Adomian solutions are presented. Expressions for the velocity, stream function, magnetic force function, temperature, pressure gradient and pressure rise are computed. The results of pertinent parameters are discussed. Finally, the trapping phenomena for different wave shapes are discussed. It is observed that the pressure rise for sinusoidal wave is less than trapezoidal wave and greater than triangular in a Jeffrey fluid. - Highlights: Black-Right-Pointing-Pointer The effects of induced magnetic field and heat transfer in peristaltic motion of a two dimensional Jeffrey fluid are discussed. Black-Right-Pointing-Pointer In this paper exact and closed form Adomian solutions are presented. Black-Right-Pointing-Pointer Different wave shapes are considered to observe the behavior of pressure rise and trapping phenomena.

  20. Influence of heat and mass transfer, initial stress and radially varying magnetic field on the peristaltic flow in an annulus with gravity field

    Energy Technology Data Exchange (ETDEWEB)

    Abd-Alla, A.M., E-mail: mohmrr@yahoo.com [Mathematics Department, Faculty of Science, Taif University 888 (Saudi Arabia); Mathematics Department, Faculty of Science, Sohag (Egypt); Abo-Dahab, S.M. [Mathematics Department, Faculty of Science, Taif University 888 (Saudi Arabia); Mathematics Department, Faculty of Science, SVU, Qena 83523 (Egypt); El-Shahrany, H.D. [Mathematics Department, Faculty of Science, Taif University 888 (Saudi Arabia)

    2014-08-01

    In this paper, the effects of both initial stress, radially varying and gravity field on the peristaltic flow of an incompressible MHD Newtonian fluid in a vertical annulus have been studied under the assumption of long wavelength and low-Reynolds number. The analytical solution has been derived for the temperature, concentration and velocity. The results for velocity, concentration and temperature obtained in the analytical form have been evaluated numerically and discussed briefly. The effect of the non-dimensional wave amplitude, the coefficient of viscosity, Sort number, Schmidt number, initial stress, gravitational field and the dimensionless time-mean flow in the wave frame are analyzed theoretically and computed numerically. The expressions for pressure rise, temperature, concentration field, velocity and pressure gradient are sketched for various embedded parameters and interpreted. Numerical results are given and illustrated graphically in each case considered. Comparison was made with the results obtained in the presence and absence of initial stress and gravitational field. - Highlights: • Initial stress, radially varying and gravity field on the peristaltic flow of MHD Newtonian fluid. • The analytical solution for the temperature, concentration and velocity. • Effect of wave amplitude, viscosity, Sort number, Schmidt number, initial stress, gravitational in the wave frame.

  1. Peristaltic propulsion of generalized Burgers' fluids through a non-uniform porous medium: a study of chyme dynamics through the diseased intestine.

    Science.gov (United States)

    Tripathi, D; Anwar Bég, O

    2014-02-01

    A mathematical study of the peristaltic flow of complex rheological viscoelastic fluids using the generalized fractional Burgers' model through a non-uniform channel is presented. This model is designed to study the movement of chyme and undigested chyme (biophysical waste materials) through the small intestine to the large intestine. To simulate blockages and impedance of debris generated by cell shedding, infections, adhesions on the wall and undigested material, a drag force porous media model is utilized. This effectively mimicks resistance to chyme percolation generated by solid matrix particles in the regime. The conduit geometry is mathematically simulated as a sinusoidal propagation with linear increment in shape of the bolus along the length of channel. A modified Darcy-Brinkman model is employed to simulate the generalized flows through isotropic, homogenous porous media, a simplified but physically robust approximation to actual clinical situations. To model the rheological properties of chyme, a viscoelastic Burgers' fluid formulation is adopted. The governing equations are simplified by assuming long wavelength and low Reynolds number approximations. Numerical and approximate analytical solutions are obtained with two semi-numerical techniques, namely the homotopy perturbation method and the variational iteration method. Visualization of the results is achieved with Mathematica software. The influence of the dominant hydromechanical and geometric parameters such as fractional viscoelastic parameters, wave number, non-uniformity constant, permeability parameter, and material constants on the peristaltic flow characteristics are depicted graphically. PMID:24300568

  2. 一种负压驱动的蠕动微型泵设计%Design of a Peristaltic Micropump Driven by Pneumatic Pressure

    Institute of Scientific and Technical Information of China (English)

    崔建国; 王洪

    2012-01-01

    微型泵作为集成微流体中不可或缺的元素,在过去20年间取得了很大的进展.基于真空负压驱动原理,研制了一种结构简单的蠕动式微型泵.微型泵由三层聚二甲基硅氧烷(PDMS)材料构成(气路层,流路层,驱动薄膜层),并通过表面等离子体氧化处理技术实现了PDMS层之间的键合封装,其全部结构均采用激光器加工制作而成.蠕动驱动模式的关键在于利用气路周期性地传递负压力波,进而实现弹性薄膜的顺序变形,其中负压源通过电磁阀(EMV)进行通断控制.这种结构简化了常规蠕动泵模型中的复杂逻辑控制.实验结果表明在50kPa负压和30Hz驱动频率的条件下,获得的最佳流速为170 μL/min.%As an indispensable element in integrated microfluidics, micropumps have gradually evolved over the past two decades. Based on vacuum-driven principle, a simple peristaltic micropump is developed. The micropump fabricated by laser mi-cromachining and plasma bonding of three polydimethylsiloxane (PDMS) layers, includes a pneumatic channel layer, actuation membrane layer, and microfluidic channel layer. As the key to peristaltic motion, the sequential deflection of the elastic membranes is achieved by periodic pressure waveforms ( negative) traveling through the pneumatic channel, provided by a vacuum source regulated by an electromagnetic valve ( EMV). This configuration eliminates the complicated control logic typically required in peristaltic motion. Experiment results show that a maximal flow rate of 170 μL min-1 has been optimized at the pulsed vacuum frequency of 30 Hz with a vacuum pressure of 50 kPa.

  3. Influence of heat and mass transfer, initial stress and radially varying magnetic field on the peristaltic flow in an annulus with gravity field

    Science.gov (United States)

    Abd-Alla, A. M.; Abo-Dahab, S. M.; El-Shahrany, H. D.

    2014-08-01

    In this paper, the effects of both initial stress, radially varying and gravity field on the peristaltic flow of an incompressible MHD Newtonian fluid in a vertical annulus have been studied under the assumption of long wavelength and low-Reynolds number. The analytical solution has been derived for the temperature, concentration and velocity. The results for velocity, concentration and temperature obtained in the analytical form have been evaluated numerically and discussed briefly. The effect of the non-dimensional wave amplitude, the coefficient of viscosity, Sort number, Schmidt number, initial stress, gravitational field and the dimensionless time-mean flow in the wave frame are analyzed theoretically and computed numerically. The expressions for pressure rise, temperature, concentration field, velocity and pressure gradient are sketched for various embedded parameters and interpreted. Numerical results are given and illustrated graphically in each case considered. Comparison was made with the results obtained in the presence and absence of initial stress and gravitational field.

  4. Thermal and velocity slip effects on the MHD peristaltic flow with carbon nanotubes in an asymmetric channel: application of radiation therapy

    Science.gov (United States)

    Akbar, Noreen Sher; Nadeem, S.; Khan, Zafar Hayat

    2014-10-01

    Peristaltic flow is used to study the flow and heat transfer of carbon nanotubes in an asymmetric channel with thermal and velocity slip effects. Two types of carbon nanotubes, namely, single- and multi-wall carbon nanotubes are utilized to see the analysis with water as base fluids. Empirical correlations are used for the thermo-physical properties of carbon nanotubes (CNTs) in terms of solid volume fraction of CNTs. The governing equations are simplified using long wavelength and low Reynolds number approximation. Exact solutions have been evaluated for velocity, pressure gradient, the solid volume fraction of CNTs and temperature profile. The effects of various flow parameters, i.e. Hatmann number M, the solid volume fraction of the nanoparticles ϕ, Grashof number G, velocity slip parameter β, thermal slip parameter γ and Prandtl number P r are presented graphically for both single- (SWCNT) and multi-wall carbon nanotubes (MWCNT).

  5. Peristaltic Flow and Heat Transfer of a Conducting Phan-Thien-Tanner Fluid in an Asymmetric Channel - Application to Chyme Movement in Small Intestine

    Science.gov (United States)

    Vajravelu, K.; Sreenadh, S.; Dhananjaya, S.; Lakshminarayana, P.

    2016-08-01

    In this paper, the influence of heat transfer on the peristaltic flow of a conducting Phan-Thien-Tanner fluid in an asymmetric channel with porous medium is studied. The coupled nonlinear governing differential equations are solved by a perturbation technique. The expressions for the temperature field, the stream function, the axial velocity, and the pressure gradient are obtained. The effects of the various physical parameters such as the magnetic parameter M, the permeability parameter σ, the Brinkman number Br and the Weissenberg number We on the pumping phenomenon are analyzed through graphs and the results are discussed in detail. It is observed that the velocity and the pressure are decreased with increasing the magnetic parameter M whereas the effect of the parameter M on the temperature field is quite the opposite.

  6. Sewer Cleaning Inspection Robot Based on Peristaltic Walking%蠕动式污水管道清淤机器人

    Institute of Scientific and Technical Information of China (English)

    曹建树; 徐宝东; 鲁军; 刘强; 张义; 黄子茂

    2014-01-01

    采用模块化方法对污水管道清淤机器人中的管道清理单元、推进舱、阀组和控制单元等模块加以组合,并对其进行了总体方案设计,给出了机器人蠕动行走液压油路方案,分析了其蠕动行走过程。介绍了系统上、下位机联合控制方案,同时描述了下位机在控制系统中的功能及其对应程序流程。在此基础上,研制了一台污水管道清淤机器人,并对其进行了实验。结果表明:该机器人在现有方案下能够实现预定的设计目标,管道清理检测质量良好,可降低工人工作强度。%By combining pipe cleaning unit,propulsion module,valves and control with modularization method,the general scheme of a novel sewer cleaning inspection robot was designed. The peristaltic walking program based on hydraulic oil circuit of the ro-bot was given,and its peristaltic walking processes were analyzed. United control scheme of the system between host and lower comput-er was introduced. At the same time,the lower computer function in control system and its corresponding program flow were described. Upon this basis,a sewer cleaning inspection robot was developed and it was verified by testing experiments. The results show that the performances of robot have a good agreement with design aim in the scheme,and inspecting effect is good,which can reduce strength of worker.

  7. Influence of Heat Source, Thermal Radiation and Inclined Magnetic Field on Peristaltic Flow of a Hyperbolic Tangent Nanofluid in a Tapered Asymmetric Channel.

    Science.gov (United States)

    Kothandapani, Munirathinam; Prakash, Jayavel

    2014-10-31

    In the present analytic thinking, we have modeled the governing equations of a two dimensional peristaltic transport of a Hyperbolic tangent nanofluid in the presence of a heat source/sink with the combined effects of thermal radiation and inclined magnetic field in a tapered asymmetric channel. The propagation of waves on the non-uniform walls to have different amplitudes and phase but the same wave speed is produced the tapered asymmetric channel. The equations of dimensionless temperature and nanoparticle concentration are solved analytically under assumptions of long wavelength and low Reynolds number. The governing equations of momentum of a hyperbolic tangent nanofluid for the tapered asymmetric channel have also been solved analytically using the regular perturbation method. The expression for average rise in pressure has been figured using numerical integrations. The effects of various physical parameters entering into the problem are discussed numerically and graphically. The phenomenon of trapping is also investigated. Furthermore, the received results show that the maximum pressure rise gets increased in case of non-Newtonian fluid when equated with Newtonian fluid. PMID:25373110

  8. Effects of rotation and magnetic field on the nonlinear peristaltic flow of a second-order fluid in an asymmetric channel through a porous medium

    Institute of Scientific and Technical Information of China (English)

    A.M.Abd-Alla; S.M.Abo-Dahab; H.D.El-Shahrany

    2013-01-01

    In this paper,the effects of both rotation and magnetic field of the peristaltic transport of a second-order fluid through a porous medium in a channel are studied analytically and computed numerically.The material is represented by the constitutive equations for a second-order fluid.Closed-form solutions under the consideration of long wavelength and low Reynolds number is presented.The analytical expressions for the pressure gradient,pressure rise,friction force,stream function,shear stress,and velocity are obtained in the physical domain.The effects of the non-dimensional wave amplitude,porosity,magnetic field,rotation,and the dimensionless time-mean flow in the wave frame are analyzed theoretically and computed numerically.Numerical results are given and illustrated graphically in each case considered.Comparison was made with the results obtained in the presence and absence of rotation,magnetic field,and porosity.The results indicate that the effects of the non-dimensional wave amplitude,porosity,magnetic field,rotation,and the dimensionless time-mean flow are very pronounced in the phenomena.

  9. Comparison of a pulsatile blood pump and a peristaltic roller pump during hemoperfusion treatment in a canine model of paraquat poisoning.

    Science.gov (United States)

    Lee, Jung Chan; Park, Chan Young; Choi, Seong Wook; Kim, Jeong Chul; Lim, Ki Moo; Kim, Kyuseok; Jung, Sung Koo; Kwak, Young Ho; Shin, Sang Do; Jo, Ik Joon; Suh, Gil Joon; Min, Byoung Goo

    2008-07-01

    This study examined the treatment efficacy and the damage to the blood during hemoperfusion for treating paraquat poisoning using two blood pump mechanisms. Paraquat-poisoned animal models were prepared. A conventional hemodialysis machine, AK90, with a peristaltic roller pump and a cardiopulmonary support system, T-PLS, with a pulsatile blood pump were used during the animal experiments. A total of 12 dogs were treated with hemoperfusion using a charcoal column. Six dogs were treated with hemoperfusion and T-PLS, and the other six were treated with AK90. A paraquat dose of 30 mg/kg was administrated by an intravenous injection. Both pumps maintained blood flow rates of 125 mL/min measured by an ultrasonic flowmeter. For anticoagulation, heparin was administrated by an initial bolus (250 IU/kg) and a continuous injection (100 IU/kg/h). During the experiments, T-PLS and AK90 showed a similar toxin removal efficacy. Both devices decreased the plasma paraquat concentration to 10% of the initial dose within 4-h hemoperfusion. The two pumps showed similar hemolysis properties with acceptable levels. Although T-PLS was developed as a cardiopulmonary bypass system, it can also be used as a hemoperfusion treatment device. PMID:18638308

  10. Cineradiography of the liquid bolus swallow. A study of the speed ot the bolus and peristaltic wave and of movement of the hyoid bone, larynx, and epiglottis

    International Nuclear Information System (INIS)

    In the evaluation of the dysphagic patient, radiology is crucial as a technique for monitoring morphology and function. In particular, high-speed cineradiography can reveal a variety of pharyngeal dysfunctions. However, in the literature and in practice the difference between normal and abnormal function is not always clear. This monography is based on high-speed cineradiographies of swallowing in 75 non-dysphagic volunteers and in 189 dysphagic patients. The purpose was to study whether differences in bolus volumes, patient position, age and gender had any effects on the following parameters: the speed of the peristaltic wave and apex of the liquid barium bolus, the length of movement and the movement pattern of the hyoid bone and larynx, and epiglottic function. The study disclosed that the speed of the bolus, the anterior-superior movement and net movement of the hyoid bone increased significantly with larger bolus volumes. The position of the individual in relation to gravity significantly influenced the speed of peristalsis. In most of the measured parameters there were no differences between non-dysphagic and dysphagic individuals expect for differences in the intrapersonal variations and in the anterior-superior movement of the hyoid bone. In patients with pharyngeal dysfunction the initial stage of the elevation of the larynx was significantly lower than in patients without dysfunction. The approximation of the thyroid cartilage to the hyoid bone was significantly greater in individuals with normal epiglottic function than in those with epiglottic dysmobility. It is suggested that abnormal speed of peristalsis may be a mild form of dysfunction. Measurements of the aforementioned speed and movements can be done if bolus volume, age and position of the patient, film speed and magnifications factors are known. Hypotheses concerning epiglottic function and central control of swallowing are proposed. (au)

  11. 流变学流体的蠕动传输:食道中食物块的运动模型%Peristaltic Transport of a Rheological Fluid:Model for Movement of Food Bolus Through Esophagus

    Institute of Scientific and Technical Information of China (English)

    J·C·密斯拉; S·麦蒂; 海治

    2012-01-01

    研究食道中蠕动传输的流体力学.对任意的波形和任意的管道长度,建立起流变学流体蠕动传输的数学模型.用粘性流体的Ostwald-de Waele幂定律,描述非Newton流体的流动特性.解析公式化模型,详细且精确地给出食物块在食道中蠕动传输相关的一些重要性质.分析中应用了润滑理论,本研究特别适合于Reynolds数不大的情况.将食道看作环形的管道,通过食道壁周期性的收缩来传输食物块.就单个波和周期性收缩一组波的传播,研究与传输过程有关变量的变化,如压力、流速、食物颗粒轨迹以及流量等.局部压力的变化,对流变指数n有着高度的敏感性.研究结果清晰地表明,食物块在食道中蠕动传输时,Newton流体或流变学流体构成的连续流体,以组合波传播比大间隔单波传播,传输效率要高得多.%Fluid mechanical peristaltic transport through esophagus had been of concern. A mathematical model had been developed with an aim to study the peristaltic transport of a rheo-logical fluid for arbitrary wave shapes and tube lengths. The Ostwald-de Waele power law of viscous fluid was considered here to depict the non-Newtonian behaviour of the fluid. The model was formulated and analyzed with the specific aim of exploring some important information concerning the movement of food bolus through the esophagus. The analysis had been carried out by using lubrication theory. The study was particularly suitable for cases where the Reynolds number was small. The esophagus was treated as a circular tube through which the transport of food bolus takes places by periodic contraction of the esophageal wall. Variation of different variables concerned with the transport phenomena such as pressure, flow velocity, particle trajectory and reflux were investigated for a single wave as well as for a train of periodic peristaltic waves. Locally variable pressure was seen to be highly sensitive to the flow index n

  12. 微极流体蠕动泵经由滑移边界管道输送的Stokes流动%Study on Stokes Flow of Micro-Polar Fluids by Peristaltic Pumping Through a Tube With Slip Boundary Condition

    Institute of Scientific and Technical Information of China (English)

    D·特里帕蒂; M·K·乔伯; P·K·古泊塔; 吴承平

    2011-01-01

    The Stokes flow of micro-polar fluids by peristaltic pumping through the cylindrical tube under the effect of slip boundary condition was studied. The motion of wall was governed by the sinusoidal wave equation. Analytical and numerical solutions for axial velocity, micro-polar vector, stream function, pressure gradient, friction force and mechanical efficiency were obtained by using the lubrication theory. The impacts of emerging parameters such as coupling number, micro-polar parameter and slip parameter on pumping characteristic, friction force and trapping phenomena were depicted graphically. Numerical computation infers that more pressure requires for peristaltic pumping when coupling number is large while opposite behavior is found for micro-polar parameter and the slip parameter. The size of trapped bolus reduces with coupling number and micro-polar parameter whereas it blows up with slip parameter.%计及管道边界条件滑移的影响,研究微极流体蠕动泵,经由圆柱形管道输运的Stokes流动.壁面运动的控制方程为正弦波方程.使用润滑理论,得到了轴向速度、微转动向量、流函数、压力梯度、摩擦力和机械效率的解析数值解.用图形表示出构成参数,如像耦合参数、微极参数和表征蠕流泵特性的滑移参数、摩擦力和俘获现象的影响.数值计算表明,当耦合参数较大时,需要蠕动泵的压力更大,而微极参数和滑移参数正相反.俘获团块的大小随耦合参数和微极参数的减小而缩小,而随滑移参数的增大而缩小.

  13. 聚二甲基硅氧烷气动微型蠕动泵制作工艺的研究%Study on Process of Polydimethyl Siloxane Pneumatic Peristaltic Micropump

    Institute of Scientific and Technical Information of China (English)

    关艳霞; 王宏; 徐章润

    2009-01-01

    聚二甲基硅氧烷(PDMS)气动微型泵由3个PDMS气动微阀构成,依靠3个微阀的蠕动作用实现输运液体的作用.PDMS气动微泵的关键制作工艺是液体通道的弧形化和PDMS层之间、PDMS层与玻璃基片之间的封接.实验证明AZ4620正性光刻胶所制作的阳模能形成剖面形状呈弧形的液体通道.采用等离子体氧化处理法封接技术实现了PDMS层之间、PDMS层与玻璃基片之间的封接,该工艺易操作,封接速度快,而且封接效果好.%A polydimethyl siloxane (PDMS) pneumatic micropump is constituted of three active pneumatic micro-valves , and the transport of liquid is realized by Peristaltic working of three valves.Major factors in the fabrication of PDMS pneumatic micropumps are the formation of arc-shaped channel profiles of the liquid channel and bonding PDMS layers as well as bonding between the PDMS layer and the glass slide.AZ4620 positive photoresist was demonstrated the best performance as a positive master for producing a liquid channel with an ideal cross sectional profile.The bonding following plasma cleaning showed the best result was used as the bonding means for fabricating PDMS pneumatic micropumps.This process was demonstrated easy to operate,fast to bond.

  14. Application of RAGAZZINI Peristaltic Pump in the Production of New-process Mixiang Baijiu(Liquor)%RAGAZZINI蠕动泵在新工艺米香型白酒生产中的应用

    Institute of Scientific and Technical Information of China (English)

    朱旭平

    2015-01-01

    新工艺米香型白酒生产线属长乐烧企业的创新项目,该项目获广东轻工科技二等奖、获国家轻工科技优秀奖。新工艺与传统工艺最大的区别在于,前者是将熟化后的原料直接加水、加曲输入发酵罐糖化、发酵同罐进行,后者是先将熟化的原料在糖化槽中糖化后加水再输入发酵罐。前者物料为液固松散分离状态,后者为糊化状态,因此常用的气动隔膜泵输送液固松散分离状态物料时就常常将液体抽走,造成管道阻塞。长乐烧酒业在新工艺生产线上利用蠕动泵实现了将熟化原料加水混合物料轻松输入发酵罐的目标,解决了管道阻塞问题,达到了连续生产目的,彻底改变了蒸饭机至发酵罐间物料自动输送的难题。%New-process Mixiang Baijiu(liquor) is the innovative program in Changle Distillery which won the 2nd Prize of Guangdong Light Industry Science and Technology and State Light Industry Science&Technology Excellent Prize. The difference between new-process produc-tion and traditional production were as follows:in the new process (raw materials in liquid&solid separation loose state), water was added di-rectly in cooked raw materials, then caky starter was added for saccharfication and fermentation in the same fermenter;in traditional process (raw materials in gelatinized state), cooked raw materials were saccharified in saccharifying tank at first, then water was added for fermentation in the fermenter. The use of new-process often induced pipe obstruction because the commonly-used pneumatic drive membrane pump drained liquid during the transportation of liquid&solid separation loose raw materials. Changle Distillery used peristaltic pump to settle such prob-lem, which could achieve continuous production and completely solve pipeline blocking from steam machine to fermenter.

  15. Rotary Peristaltic Micro-Pump Based on the Nano-Magnetic Fluid%基于纳米磁性液体的旋转式蠕动微泵

    Institute of Scientific and Technical Information of China (English)

    吴健; 刘同冈; 张亮

    2013-01-01

    A rotary peristaltic micro-pump based on the nano-magnetic fluid was designed,which was composed of an upper substrate,a lower substrate and an elastic film positioned between the two substrates.A micro-channel was machined on each substrate,the magnetic fluid in the upper micro-channel was gathered by a permanent magnet to deform the elastic film in order to push the sample liquid in the lower micro-channel.Both micro-channels were designed with the ring structure to pump the liquid continuously.The operational result indicates that the flow rate and output pressure are the combination result of the positive pressure generated by the gradient magnetic field and the driving force produced by the moving magnetic field.When the rotational speed of the magnetic field is 6 r/min,the maximum output pressure and flow rate of the micro-pump are 1 600 Pa and 1.8 mL/min,respectively.%设计了一种基于纳米磁性液体的旋转式蠕动微泵.泵体由上、下基板和弹性薄膜组成,弹性薄膜位于上、下基板的中间位置.在上、下基板上分别加工出微型管道,上管道中的纳米磁性液体在磁场作用下压迫弹性薄膜变形,从而推动下管道中的液体流动,并且采用环形结构,实现连续泵送的目的.运行结果显示:泵送流量和泵送压力是梯度磁场产生的正压力与移动磁场产生的驱动力共同作用的结果.当磁场旋转速度达到6 r/min时,微泵产生的最大泵送压力达1 600 Pa,此时的流量为1.8 mL/min.

  16. Application of RAGAZZINI Peristaltic Pump in the Production of New-process Mixiang Baijiu(Liquor)%RAGAZZINI蠕动泵在新工艺米香型白酒生产中的应用

    Institute of Scientific and Technical Information of China (English)

    朱旭平

    2015-01-01

    New-process Mixiang Baijiu(liquor) is the innovative program in Changle Distillery which won the 2nd Prize of Guangdong Light Industry Science and Technology and State Light Industry Science&Technology Excellent Prize. The difference between new-process produc-tion and traditional production were as follows:in the new process (raw materials in liquid&solid separation loose state), water was added di-rectly in cooked raw materials, then caky starter was added for saccharfication and fermentation in the same fermenter;in traditional process (raw materials in gelatinized state), cooked raw materials were saccharified in saccharifying tank at first, then water was added for fermentation in the fermenter. The use of new-process often induced pipe obstruction because the commonly-used pneumatic drive membrane pump drained liquid during the transportation of liquid&solid separation loose raw materials. Changle Distillery used peristaltic pump to settle such prob-lem, which could achieve continuous production and completely solve pipeline blocking from steam machine to fermenter.%新工艺米香型白酒生产线属长乐烧企业的创新项目,该项目获广东轻工科技二等奖、获国家轻工科技优秀奖。新工艺与传统工艺最大的区别在于,前者是将熟化后的原料直接加水、加曲输入发酵罐糖化、发酵同罐进行,后者是先将熟化的原料在糖化槽中糖化后加水再输入发酵罐。前者物料为液固松散分离状态,后者为糊化状态,因此常用的气动隔膜泵输送液固松散分离状态物料时就常常将液体抽走,造成管道阻塞。长乐烧酒业在新工艺生产线上利用蠕动泵实现了将熟化原料加水混合物料轻松输入发酵罐的目标,解决了管道阻塞问题,达到了连续生产目的,彻底改变了蒸饭机至发酵罐间物料自动输送的难题。

  17. Single Crystal Bimorph Array Driven Deformable Mirrors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research (SBIR) Phase I project will research a novel deformable mirror design for NASA adaptive optics telescope applications . The...

  18. Magnetic plucking of piezoelectric bimorphs for a wearable energy harvester

    Science.gov (United States)

    Pozzi, Michele

    2016-04-01

    A compact and low-profile energy harvester designed to be worn on the outside of the knee-joint is presented. Frequency up-conversion has been widely adopted in recent times to exploit the high frequency response of piezoelectric transducers within environments where only low frequencies are present. Contactless magnetic plucking is here introduced, in a variable reluctance framework, with the aim of improving the mechanical energy transfer into the transducers, which is sub-optimal with contact plucking. FEA and experiments were used to design an optimal arrangement of ferromagnetic teeth to interact with the magnets fixed to the piezoelectric beams. A prototype was made and extensively tested in a knee-joint simulator controlled with gait data available in the literature. Energy and power produced were measured for walking and running steps. A power management unit was developed using off-the-shelf components, permitting the generation of a stable and regulated supply of 26 mW at 3.3 V during walking. Record levels of rectified (unregulated) electrical power of over 50 and 70 mW per walking and running steps, respectively, were measured.

  19. Single Crystal Bimorph Array (SCBA) Driven Deformable Mirror (DM) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research (SBIR) Phase II project will research a novel deformable mirror design for NASA adaptive optics telescope applications. The...

  20. Fabrication of a peristaltic micro pump with novel cascaded actuators

    International Nuclear Information System (INIS)

    This paper presents the fabrication of an all-PDMS (polydimethylsiloxane) micro pump with novel cascaded actuators as dynamic valves. The micro pump consists of three pneumatic actuators in series and a micro fluidic channel connecting two fluidic inlet and outlet ports. The three-layer bonded pump structure is fabricated through a typical moulding process of PDMS and a simple heating process for the PDMS-to-PDMS bonding. The total size of the micro pump is 5 mm × 5 mm. The dynamic valve pattern of the single actuator is observed under various operational conditions of the square-wave input signal for the estimation of its volume stroke. The maximum volume stroke of the pneumatic actuator for liquid is about 85% of the volume of the liquid chamber. Three types of liquid-pumping tests are performed for characterization of the micro pump such as backpressure, frequency and viscous liquids. The flow rate of the de-ionized (DI) water is about 73.9 nl min−1 at zero backpressure. As the hydraulic difference between inlet and outlet ports increases, the flow rate gradually decreases. In the case of the frequency responses, the micro pump has the maximum flow rate of the DI water at 2 Hz. The viscosity-dependent flow rate of the working fluids is also observed

  1. Evaluation of peristaltic micromixers for highly integrated microfluidic systems.

    Science.gov (United States)

    Kim, Duckjong; Rho, Hoon Suk; Jambovane, Sachin; Shin, Soojeong; Hong, Jong Wook

    2016-03-01

    Microfluidic devices based on the multilayer soft lithography allow accurate manipulation of liquids, handling reagents at the sub-nanoliter level, and performing multiple reactions in parallel processors by adapting micromixers. Here, we have experimentally evaluated and compared several designs of micromixers and operating conditions to find design guidelines for the micromixers. We tested circular, triangular, and rectangular mixing loops and measured mixing performance according to the position and the width of the valves that drive nanoliters of fluids in the micrometer scale mixing loop. We found that the rectangular mixer is best for the applications of highly integrated microfluidic platforms in terms of the mixing performance and the space utilization. This study provides an improved understanding of the flow behaviors inside micromixers and design guidelines for micromixers that are critical to build higher order fluidic systems for the complicated parallel bio/chemical processes on a chip. PMID:27036809

  2. Evaluation of peristaltic micromixers for highly integrated microfluidic systems

    Science.gov (United States)

    Kim, Duckjong; Rho, Hoon Suk; Jambovane, Sachin; Shin, Soojeong; Hong, Jong Wook

    2016-03-01

    Microfluidic devices based on the multilayer soft lithography allow accurate manipulation of liquids, handling reagents at the sub-nanoliter level, and performing multiple reactions in parallel processors by adapting micromixers. Here, we have experimentally evaluated and compared several designs of micromixers and operating conditions to find design guidelines for the micromixers. We tested circular, triangular, and rectangular mixing loops and measured mixing performance according to the position and the width of the valves that drive nanoliters of fluids in the micrometer scale mixing loop. We found that the rectangular mixer is best for the applications of highly integrated microfluidic platforms in terms of the mixing performance and the space utilization. This study provides an improved understanding of the flow behaviors inside micromixers and design guidelines for micromixers that are critical to build higher order fluidic systems for the complicated parallel bio/chemical processes on a chip.

  3. A peristaltic pump driven 89Zr separation module

    DEFF Research Database (Denmark)

    Siikanen, J.; Peterson, M.; Tran, T.;

    2012-01-01

    To facilitate the separation of 89Zr produced in yttrium foils, an automated separation module was designed and assembled. The module separates more than 85% of produced 89Zr - activity in 3 g foils in less than 90 min. About 10 % remains in the dissolving vial. The quality of the separated 89Zr...

  4. A peristaltic pump driven 89Zr separation module

    DEFF Research Database (Denmark)

    Siikanen, J.; Peterson, M.; Tran, T.;

    2012-01-01

    To facilitate the separation of 89Zr produced in yttrium foils, an automated separation module was designed and assembled. The module separates more than 85% of produced 89Zr - activity in 3 g foils in less than 90 min. About 10 % remains in the dissolving vial. The quality of the separated 89Zr ...... activity was investigated for labeling of the HER2-binding monoclonal antibody fragment, trastuzumab-Fab....

  5. Vibration energy harvesting in railway tunnels with a wireless sensor node application

    Energy Technology Data Exchange (ETDEWEB)

    Wischke, Martin

    2012-07-01

    Vibration harvesting is a promising concept to prolong the lifetime of batterypowered stand-alone systems, or even to enable their energy-autonomy. This thesis focuses on ambient vibrations converted by electromechanical transducers into electricity. The final goal is energy scavenging from train-induced vibrations in railway tunnels. This is achieved via the development of a suitable harvester for this environment and the practical demonstration of a vibrationpowered wireless sensor node (WSN). At the beginning of this thesis, extensive vibration measurements were performed in several traffic tunnels. The obtained unique data set formed the basis for the design and test of several harvesters. The railway sleeper was chosen as usable harvester location. A shock-resistant double-side suspended piezoelectric cantilever was developed. Several cantilevers with different eigenfrequencies are combined in an array, creating a robust harvester with a broad bandwidth. A field test of 7 days in the Loetschbergbasis-tunnel verified that, on average the sufficient energy for powering a virtual wireless sensor node was scavenged. For application in a real WSN, the harvester array was scaled up to 10 cantilevers. The power management for the sensor node was developed concurrently. The central component is a power switch that monitors the energy level in the system's storage capacitor and only triggers the wireless interface when sufficient energy is available. Combined with a train detection circuit, the presented energy-autonomous WSN reliably reports every passing vehicle. In addition to the development of an energy-autonomous fully integrated WSN, this work investigates nonlinear properties of PZT ceramics. Consideration of the elastostriction and the electrostriction enables a more precises prediction of the tip displacement of a piezoelectric cantilever actuator. Further, the elastostriction is exploited to modify the resonance frequency of a bimorph cantilever. Basing

  6. Screen printed PZT/PZT thick film bimorph MEMS cantilever device for vibration energy harvesting

    DEFF Research Database (Denmark)

    Xu, Ruichao; Lei, Anders; Dahl-Petersen, Christian;

    2012-01-01

    elements. We show experimental results from two types PZT/PZT harvesting devices, one where the Pb(ZrxTi1−x)O3 (PZT) thick films are high pressure treated during the fabrication and the other where the treatment is omitted. We find that with the high pressure treatment prior to PZT sintering, the films...

  7. Herstellung und In-situ-Charakterisierung von Formgedächtnis-Bimorph-Nanoaktoren

    OpenAIRE

    Lay, Christian Wilhelm

    2015-01-01

    Zur Entwicklung zukünftiger nanoskopischer Manipulatoren als ein Bestandteil intelligenter Nanosysteme werden neue Aktorkonzepte gesucht. Ziel dieser Arbeit ist die Entwicklung von Nanoaktoren aus der Formgedächtnislegierung Ni-Mn-Ga und die In-situ-Untersuchung ihrer thermomechanischen Eigenschaften. Die hier präsentierten Ergebnisse zeigen erstmalige gleichzeitige Messungen mehrerer Eigenschaften von Ni-Mn-Ga-Nanoaktoren, mit denen ein Größeneffekt in Ni-Mn-Ga identifiziert werden kann.

  8. Implementation of an Algorithm for the Locomotion of Quadruped Robot with Bimorph Insect Leg.

    Directory of Open Access Journals (Sweden)

    Gabriel Duarte Gonçalves Pedro

    2015-05-01

    Full Text Available In the last decades the rising of higher processing power computers, together with more sophisticated robot actuators gave an impulse to the field of autonomous robots in robotics. The need to explore dirty, dangerous and difficult terrains is a suitable task for a robot, sparing a human from hazards of the environment. Even though wheeled robots have been used in great scale for explorations, its configuration has the downside of obstacle impediment and depending on the terrain its wheels can get stuck. The legged robot presents more versatility allowing him to surpass such obstacles in some cases. This article presents the continuation of the development of an quadruped robot with biomorphic insect leg.

  9. NOTE: Single-mask microfabrication of three-dimensional objects from strained bimorphs

    Science.gov (United States)

    Moiseeva, E.; Senousy, Y. M.; McNamara, S.; Harnett, C. K.

    2007-09-01

    Recently, techniques known as 'micro-origami' or 'strain architecture' have emerged for the fabrication of out-of-plane micro- and nanostructures by relaxation of a pair of strain-mismatched thin films. Applications of such structures include optical reflectors, actuators and micropositioners. We illustrate how control of the folding order can generate complex three-dimensional objects from metal-oxide bilayers using this approach. By relying on the fact that narrower structures are released from the substrate first, it is possible to create multi-axis loops and interlinked objects with several sequential release steps, using a single photomask. The structures remain planar until released by XeF2 dry silicon etching, making it possible to integrate them with other MEMS and microelectronic devices early in the process.

  10. MHD peristaltic motion of Johnson-Segalman fluid in a channel with compliant walls

    Energy Technology Data Exchange (ETDEWEB)

    Hayat, T. [Department of Mathematics, Quaid-i-Azam University, Islamabad 44000 (Pakistan)], E-mail: t_pensy@hotmail.com; Javed, Maryiam [Department of Mathematics, Quaid-i-Azam University, Islamabad 44000 (Pakistan); Asghar, S. [Department of Mathematical Sciences, COMSATS Institute of Information Technology, H-8, Islamabad (Pakistan)

    2008-07-21

    A mathematical model for magnetohydrodynamic (MHD) flow of a Johnson-Segalman fluid in a channel with compliant walls is analyzed. The flow is engendered due to sinusoidal waves on the channel walls. A series solution is developed for the case in which the amplitude ratio is small. Our computations show that the mean axial velocity of a Johnson-Segalman fluid is smaller than that of a viscous fluid. The variations of various interesting dimensionless parameters are graphed and discussed.

  11. Peristaltic motion of a Johnson-Segalman fluid in a planar channel

    Directory of Open Access Journals (Sweden)

    Hayat T.

    2003-01-01

    Full Text Available This paper is devoted to the study of the two-dimensional flow of a Johnson-Segalman fluid in a planar channel having walls that are transversely displaced by an infinite, harmonic travelling wave of large wavelength. Both analytical and numerical solutions are presented. The analysis for the analytical solution is carried out for small Weissenberg numbers. (A Weissenberg number is the ratio of the relaxation time of the fluid to a characteristic time associated with the flow. Analytical solutions have been obtained for the stream function from which the relations of the velocity and the longitudinal pressure gradient have been derived. The expression of the pressure rise over a wavelength has also been determined. Numerical computations are performed and compared to the perturbation analysis. Several limiting situations with their implications can be examined from the presented analysis.

  12. Peristaltic Motion of Power-Law Fluid with Heat and Mass Transfer

    Institute of Scientific and Technical Information of China (English)

    T.Hayat; S.Hina; Awatif A.Hendi

    2011-01-01

    @@ The effects of wall properties and heat and mass transfer on the peristalsis in a power-law fluid are investigated.The solutions for the stream function, temperature, concentration and heat transfer coefficient are obtained.The axial velocity, temperature and mass concentration are studied for different emerging parameters.

  13. Mechanisms of Barrett's oesophagus (clinical): LOS dysfunction, hiatal hernia, peristaltic defects.

    Science.gov (United States)

    Roman, Sabine; Kahrilas, Peter J

    2015-02-01

    Barrett's oesophagus, with the potential to develop into oesophageal adenocarcinoma (OAC), is a major complication of gastrooesophageal reflux disease (GORD). However, about 50% of patients developing OAC had no known GORD beforehand. Hence, while GORD symptoms, oesophagitis, and Barrett's have a number of common determinants (oesophagogastric junction (OGJ) incompetence, impaired oesophageal clearance mechanisms, hiatus hernia) they also have some independent determinants. Further, although excess oesophageal acid exposure plays a major role in the genesis of long-segment Barrett's oesophagus there is minimal evidence supporting this for short-segment Barrett's. Hence, these may have unique pathophysiological features as well. Long-segment Barrett's seems to share most, if not all, of the risk factors for oesophagitis, particularly high-grade oesophagitis. However, it is uncertain if OGJ function and acid clearance are more severely impaired in patients with long-segment Barrett's compared to patients with high-grade oesophagitis. With respect to short-segment Barrett's, the acid pocket may play an important pathogenic role. Conceptually, extension of the acid pocket into the distal oesophagus, also known as intra-sphincteric reflux, provides a mechanism or acid exposure of the distal osophageal mucosa without the occurrence of discrete reflux events, which are more likely to prompt reflux symptoms and lead to the development of oesophagitis. Hence, intra-sphincteric reflux related to extension of the acid/no acid interface at the proximal margin of the acid pocket may be key in the development of short segment Barrett's. However, currently this is still somewhat speculative and further studies are required to confirm this. PMID:25743453

  14. A handy-motion driven, frequency up-converted hybrid vibration energy harvester using PZT bimorph and nonmagnetic ball

    Science.gov (United States)

    Halim, M. A.; Cho, H. O.; Park, J. Y.

    2014-11-01

    We have presented a frequency up-converted hybrid type (Piezoelectric and Electromagnetic) vibration energy harvester that can be used in powering portable and wearable smart devices by handy motion. A transverse impact mechanism has been employed for frequency up-conversion. Use of two transduction mechanisms increases the output power as well as power density. The proposed device consists of a non-magnetic spherical ball (freely movable at handy motion frequency) to impact periodically on the parabolic top of a piezoelectric (PZT) cantilevered mass by sliding over it, allowing it to vibrate at its higher resonant frequency and generates voltage by virtue of piezoelectric effect. A magnet attached to the cantilever vibrates along with it at the same frequency and a relative motion between the magnet and a coil placed below it, induces emf voltage across the coil terminals as well. A macro-scale prototype of the harvester has been fabricated and tested by handy motion. With an optimum magnet-coil overlap, a maximum 0.98mW and 0.64mW peak powers have been obtained from the piezoelectric and the electromagnetic transducers of the proposed device while shaken, respectively. It offers 84.4μWcm-3 peak power density.

  15. Numerical analysis for peristaltic transport of Carreau-Yasuda fluid with variable thermal conductivity and convective conditions

    Institute of Scientific and Technical Information of China (English)

    F M Abbasi; T Hayat; B Ahmad

    2015-01-01

    Peristalsis of Carreau-Yasuda fluid is investigated. Analysis is carried out in the presence of velocity slip and convective boundary conditions. Thermal conductivity of the fluid is taken to be temperature dependent. Lubrication analysis is used in the formulation of the problem. Resulting nonlinear system of equations is solved numerically. Impact of embedded parameters on the quantities of interest is examined through graphs and tables. Comparison of the behavior of the Carreau-Yasuda, Carreau and Newtonian fluid models is presented. Results show that the heat transfer rate at the wall for the Carreau fluid model is large when compared with the Newtonian or the Carreau-Yasuda fluid model. Also the heat transfer rate at the wall decreases with increase in the velocity slip and variable thermal conductivity parameters. Further, an increase in the Biot number reduces the fluid temperature by a considerable amount.

  16. Spontaneous peristaltic airway contractions propel lung liquid through the bronchial tree of intact and fetal lung explants.

    Science.gov (United States)

    Schittny, J C; Miserocchi, G; Sparrow, M P

    2000-07-01

    Spontaneous contractions of the fetal airways are a well recognized but poorly characterized phenomenon. In the present study spontaneous narrowing of the airways was analyzed in freshly isolated lungs from early to late gestation in fetal pigs and rabbits and in cultured fetal mouse lungs. Propagating waves of contraction traveling proximal to distal were observed in fresh lungs throughout gestation which displaced the lung liquid along the lumen. In the pseudoglandular and canalicular stages (fetal pigs) the frequency ranged from 2.3 to 3.3 contractions/min with a 39 to 46% maximum reduction of lumen diameter. In the saccular stage (rabbit) the frequency was 10 to 12/min with a narrowing of approximately 30%. In the organ cultures the waves of narrowing started at the trachea in whole lungs, or at the main bronchus in lobes (5.2 +/- 1.5 contractions/min, 22 +/- 8% reduction of lumen diameter), and as they proceeded distally along the epithelial tubes the luminal liquid was shifted toward the terminal tubules, which expanded the endbuds. As the tubules relaxed the flow of liquid was reversed. Thus the behavior of airway smooth muscle in the fetal lung is phasic in type (like gastrointestinal muscle) in contrast to that in postnatal lung, where it is tonic. An intraluminal positive pressure of 2.33 +/- 0.77 cm H(2)O was recorded in rabbit fetal trachea. It is proposed that the active tone of the smooth muscle maintains the positive intraluminal pressure and acts as a stimulus to lung growth via the force exerted across the airway wall and adjacent parenchyma. The expansion of the compliant endbuds by the fluid shifts at the airway tip may promote their growth into the surrounding mesenchyme.

  17. Buttressing staples with cholecyst-derived extracellular matrix (CEM) reinforces staple lines in an ex vivo peristaltic inflation model.

    LENUS (Irish Health Repository)

    Burugapalli, Krishna

    2008-11-01

    Staple line leakage and bleeding are the most common problems associated with the use of surgical staplers for gastrointestinal resection and anastomotic procedures. These complications can be reduced by reinforcing the staple lines with buttressing materials. The current study reports the potential use of cholecyst-derived extracellular matrix (CEM) in non-crosslinked (NCEM) and crosslinked (XCEM) forms, and compares their mechanical performance with clinically available buttress materials [small intestinal submucosa (SIS) and bovine pericardium (BP)] in an ex vivo small intestine model.

  18. Design and experimental gait analysis of a multi-segment in-pipe robot inspired by earthworm's peristaltic locomotion

    Science.gov (United States)

    Fang, Hongbin; Wang, Chenghao; Li, Suyi; Xu, Jian; Wang, K. W.

    2014-03-01

    This paper reports the experimental progress towards developing a multi-segment in-pipe robot inspired by earthworm's body structure and locomotion mechanism. To mimic the alternating contraction and elongation of a single earthworm's segment, a robust, servomotor based actuation mechanism is developed. In each robot segment, servomotor-driven cords and spring steel belts are utilized to imitate the earthworm's longitudinal and circular muscles, respectively. It is shown that the designed segment can contract and relax just like an earthworm's body segment. The axial and radial deformation of a single segment is measured experimentally, which agrees with the theoretical predictions. Then a multisegment earthworm-like robot is fabricated by assembling eight identical segments in series. The locomotion performance of this robot prototype is then extensively tested in order to investigate the correlation between gait design and dynamic locomotion characteristics. Based on the principle of retrograde peristalsis wave, a gait generator is developed for the multi-segment earthworm-like robot, following which gaits of the robot can be constructed. Employing the generated gaits, the 8-segment earthworm-like robot can successfully perform both horizontal locomotion and vertical climb in pipes. By changing gait parameters, i.e., with different gaits, locomotion characteristics including average speed and anchor slippage can be significantly tailored. The proposed actuation method and prototype of the multi-segment in-pipe robot as well as the gait generator provide a bionic realization of earthworm's locomotion with promising potentials in various applications such as pipeline inspection and cleaning.

  19. Modeling and optimal design of multilayer thermal cantilever microactuators

    Institute of Scientific and Technical Information of China (English)

    FU JianYu; CHEN DaPeng; YE TianChun; JIAO BinBin; OU Yi

    2009-01-01

    A model of curvature and tip deflection of multilayer thermal cantilever actuators is derived. The sim-plified expression received from the model avoids inverting complex matrices enhances understanding and makes it easier to optimize the structure parameters. Experiment is performed, the modeled andexperimental results demonstrate the validity of the model, and it also indicates that ~oung's module makes great contribution to the deflection; therefore, thin layers cannot be ignored arbitrarily.

  20. Modeling and optimal design of multilayer thermal cantilever microactuators

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A model of curvature and tip deflection of multilayer thermal cantilever actuators is derived.The sim-plified expression received from the model avoids inverting complex matrices enhances understanding and makes it easier to optimize the structure parameters.Experiment is performed,the modeled and experimental results demonstrate the validity of the model,and it also indicates that Young’s module makes great contribution to the deflection;therefore,thin layers cannot be ignored arbitrarily.

  1. Improvements in the technique of vascular perfusion-fixation employing a fluorocarbon-containing perfusate and a peristaltic pump controlled by pressure feedback

    DEFF Research Database (Denmark)

    Rostgaard, J; Qvortrup, K; Poulsen, Steen Seier

    1993-01-01

    oxygenated fluorocarbon to glutaraldehyde perfusate-fixatives, enough oxygen is made accessible for cellular respiration as well as for the oxygen-consuming chemical reactions of glutaraldehyde with the tissue. Data on anaesthesia, operative manoeuvres, mechanical components of the system, preparation...

  2. Effect of cross sectional geometry on PDMS micro peristaltic pump performance: comparison of SU-8 replica molding vs. micro injection molding.

    Science.gov (United States)

    Graf, Neil J; Bowser, Michael T

    2013-10-01

    Two different fabrication methods were employed to fabricate micropumps with different cross-sectional channel geometries. The first was to fabricate rectangular cross-sectional microchannel geometries using the well known fabrication method of replica molding (REM). The second, and far less utilized fabrication technique, was to create microchannel molds using an in-house fabricated handheld micro injection molding apparatus. The injection mold apparatus was designed for use with elastomeric room temperature vulcanization (RTV) polymers, as opposed to most other injection molding machines, which are designed for use with thermoplastic polymers. The injection mold's bottom plate was used as a microchannel molding template. The molding template was created by threading a small-diameter wire (150 μm or less) through the injection mold's bottom plate, with subsequent adhesion and smoothing of a thin piece of aluminum foil over the wire-raised injection mold template. When molded against, the template produced a rounded/Gaussian-shaped PDMS microchannel. The design of the injection mold will be presented, along with a direct comparison for micropump performance metrics such as flow rate, valving characteristics, and maximum backpressures attainable for each of the respective micropump channel geometries. PMID:23917263

  3. Problems with cryogenic operation of piezoelectric bending elements

    Science.gov (United States)

    Duffield, C. L.; Moreland, John; Fickett, F. R.

    1986-05-01

    Piezoelectric bimorphs constructed from lead titanate-zirconate (PZT) ceramic bonded to a brass sheet have been tested at cryogenic temperatures to determine their suitability for use in a low-temperature micropositioner. Experimental data are presented on bimorph sensitivity (displacement per volt) as a function of the number of temperature cycles. Results indicate that bimorphs of this type cannot be calibrated because of irreversible changes in the bending characteristics that occur while cycling from room temperature to 4 K.

  4. An Atomic Force Microscope with Dual Actuation Capability for Biomolecular Experiments

    Science.gov (United States)

    Sevim, Semih; Shamsudhin, Naveen; Ozer, Sevil; Feng, Luying; Fakhraee, Arielle; Ergeneman, Olgaç; Pané, Salvador; Nelson, Bradley J.; Torun, Hamdi

    2016-06-01

    We report a modular atomic force microscope (AFM) design for biomolecular experiments. The AFM head uses readily available components and incorporates deflection-based optics and a piezotube-based cantilever actuator. Jetted-polymers have been used in the mechanical assembly, which allows rapid manufacturing. In addition, a FeCo-tipped electromagnet provides high-force cantilever actuation with vertical magnetic fields up to 0.55 T. Magnetic field calibration has been performed with a micro-hall sensor, which corresponds well with results from finite element magnetostatics simulations. An integrated force resolution of 1.82 and 2.98 pN, in air and in DI water, respectively was achieved in 1 kHz bandwidth with commercially available cantilevers made of Silicon Nitride. The controller and user interface are implemented on modular hardware to ensure scalability. The AFM can be operated in different modes, such as molecular pulling or force-clamp, by actuating the cantilever with the available actuators. The electromagnetic and piezoelectric actuation capabilities have been demonstrated in unbinding experiments of the biotin-streptavidin complex.

  5. Development of piezoelectric-based membranes for synthetic jet actuators: experiments and modeling

    Science.gov (United States)

    Housley, Kevin W.; Clingman, Dan J.; Amitay, Michael

    2016-04-01

    A mathematical model was developed to represent the behavior of circular piezoelectric bimorphs in a synthetic jet actuator. Synthetic jet actuators are popular active flow control devices whose application is being widely explored in aerodynamics. The material properties were matched to those of PZT-5A mounted on a substrate. The actuator's geometry consisted of a cylindrical cavity of low height to diameter aspect ratio. A bimorph formed one of the cylinder's bases. The ingestion/expulsion orifice for the synthetic jet actuator was placed in the edge of the cavity so as to allow for either the present single bimorph or future dual bimorph configurations. Simply supported and rigidly supported boundary conditions were assessed around the circumference of the bimorph. The potential of alternate mode shapes occurring in the bimorphs during operation of the synthetic jet was evaluated. A limited parametric study was conducted varying the thickness of the piezoelectric wafers used in the bimorphs and the geometry of the cavity and orifice. Results were obtained for the displacement of the center of the bimorph's surface and the peak velocity of the air being ingested and expulsed through the orifice. These results were compared to values obtained through a mathematical model. Experimental data present in literature were also compared. The mathematical model was seen to have considerable potential for predicting the performance of synthetic jet actuators and their resonant frequencies but failed to capture the effects of acoustic coupling with the cavity, which is a topic of future research.

  6. 不对称柔性壁管道内幂律流体蠕动传输的精确解%Exact Solution for Peristaltic Transport of Power-Law Fluid in an Asymmetric Channel With Compliant Walls

    Institute of Scientific and Technical Information of China (English)

    T·哈亚特; M·贾佛德1; 黄绍红

    2010-01-01

    在不对称管道内,研究了壁面柔曲性对非Newton流体蠕动流的影响.流变学性质由幂律流体本构方程表征.在数学表达中,采用了长波和低Reynolds数近似.得到了流函数和速度的精确解.给出了流线图及其俘获现象.对所讨论的流动,陈列了关键参数的显著特征,并最后给出了主要结论.

  7. Getting Started with PEAs-Based Flapping-Wing Mechanisms for Micro Aerial Systems

    Directory of Open Access Journals (Sweden)

    José Carlos Durán Hernández

    2016-05-01

    Full Text Available This paper introduces recent advances on flapping-wing Micro and Nano Aerial Vehicles (MAVs and NAVs based on Piezoelectric Actuators (PEA. Therefore, this work provides essential information to address the development of such bio-inspired aerial robots. PEA are commonly used in micro-robotics and precise positioning applications (e.g., micro-positioning and micro-manipulation, whereas within the Unmanned Aerial Vehicles (UAVs domain, motors are the classical actuators used for rotary or fixed-wing configurations. Therefore, we consider it pertinent to provide essential information regarding the modeling and control of piezoelectric cantilever actuators to accelerate early design and development stages of aerial microrobots based on flapping-wing systems. In addition, the equations describing the aerodynamic behavior of a flapping-wing configuration are presented.

  8. Mechanical behavior simulation of MEMS-based cantilever beam using COMSOL multiphysics

    Energy Technology Data Exchange (ETDEWEB)

    Acheli, A., E-mail: aacheli@cdta.dz; Serhane, R. [Centre de Développement des Technologies Avancées (CDTA). BP n°17 Baba Hassen, Alger (Algeria)

    2015-03-30

    This paper presents the studies of mechanical behavior of MEMS cantilever beam made of poly-silicon material, using the coupling of three application modes (plane strain, electrostatics and the moving mesh) of COMSOL Multi-physics software. The cantilevers playing a key role in Micro Electro-Mechanical Systems (MEMS) devices (switches, resonators, etc) working under potential shock. This is why they require actuation under predetermined conditions, such as electrostatic force or inertial force. In this paper, we present mechanical behavior of a cantilever actuated by an electrostatic force. In addition to the simplification of calculations, the weight of the cantilever was not taken into account. Different parameters like beam displacement, electrostatics force and stress over the beam have been calculated by finite element method after having defining the geometry, the material of the cantilever model (fixed at one of ends but is free to move otherwise) and his operational space.

  9. Modulated interaction in double-layer shape memory-based micro-designed actuators

    Science.gov (United States)

    Crăciunescu, Corneliu; Ercuta, Aurel

    2015-12-01

    The effect of superposed transitions in actuators with layered shape memory alloy (SMA) films undergoing martensitic phase transformation is analyzed in terms of a model developed for two layers of different composition, deposited at the same temperature on a substrate. A significant difference is observed in the actuation versus temperature relationship, depending on the thermal and elastic properties of the SMA layers and their martensitic transformation temperature. The prediction of the actuation is exemplified using a multilayer model and is verified for a cantilever actuator with NiTi and NiMnGa layers deposited on a Si substrate. The model sets the ground for a smart selection of SMAs in order to achieve a modulated actuation.

  10. Feedforward and output feedback control of a highly oscillating and nonlinear 2-DOF piezoelectric actuator by using input shaping compensator and a linear quadratic regulator

    Science.gov (United States)

    Al Hamidi, Yasser; Rakotondrabe, Micky

    2016-05-01

    This paper deals with the control of a two degrees of freedom (2-DOF) piezoelectric cantilever actuator which is characterized by badly damped oscillations, hysteresis nonlinearity and cross-couplings. First, a feedforward control scheme based on the zero placement technique is introduced to annihilate the oscillations. Then a disturbance observer and a disturbance compensator are introduced to reduce the effects of low frequencies phenomena (hysteresis and creep) which were approximated by a fictive disturbance. Finally an output feedback scheme based on the linear quadratic regulator is added in order to reduce the cross-couplings effects to improve the tracking performances, and eventually to add robustness. Experiments were carried out and confirm the predicted performances.

  11. A piezoelectrically actuated ball valve

    Science.gov (United States)

    Erwin, L. R.; Schwartz, H. W.; Teitelbaum, B. R.

    1972-01-01

    Bimorph strip composed of two layers of poled piezoelectric ceramic material closes and opens valve. Strip performs like capacitator, allowing initial inrush of current when valve is energized and then only small leakage current flows as valve remains energized.

  12. Figure Control of Lightweight Optical Structures

    Science.gov (United States)

    Main, John A.; Song, Haiping

    2005-01-01

    The goal of this paper is to demonstrate the use of fuzzy logic controllers in modifying the figure of a piezoceramic bimorph mirror. Non-contact electron actuation technology is used to actively control a bimorph mirror comprised two PZT-5H wafers by varying the electron flux and electron voltages. Due to electron blooming generated by the electron flux, it is difficult to develop an accurate control model for the bimorph mirror through theoretical analysis alone. The non-contact shape control system with electron flux blooming can be approximately described with a heuristic model based on experimental data. Two fuzzy logic feedback controllers are developed to control the shape of the bimorph mirror according to heuristic fuzzy inference rules generated from previous experimental results. Validation of the proposed fuzzy logic controllers is also discussed.

  13. Design and characterisation of a piezoelectric knee-joint energy harvester with frequency up-conversion through magnetic plucking

    Science.gov (United States)

    Kuang, Yang; Yang, Zhihao; Zhu, Meiling

    2016-08-01

    Piezoelectric energy harvesting from human motion is challenging because of the low energy conversion efficiency at a low-frequency excitation. Previous studies by the present authors showed that mechanical plucking of a piezoelectric bimorph cantilever was able to provide frequency up-conversion from a few hertz to the resonance frequency of the cantilever, and that a piezoelectric knee-joint energy harvester (KEH) based on this mechanism was able to generate sufficient energy to power a wireless sensor node. However, the direct contact between the bimorph and the plectra leads to reduced longevity and considerable noise. To address these limitations, this paper introduces a magnetic plucking mechanism to replace the mechanical plucking in the KEH, where primary magnets (PM) actuated by knee-joint motion excite the bimorphs through a secondary magnet (SM) fixed on the bimorphs tip and so achieve frequency up-conversion. The key parameters of the new KEH that affect the energy output of a plucked bimorph were investigated. It was found that the bimorph plucked by a repulsive magnetic force produced a higher energy output than an attractive force. The energy output peaked at 32 PMs and increased with a decreasing gap between PM and SM as well as an increasing rotation speed of the PMs. Based on these investigations, a KEH with high energy output was prototyped, which featured 8 piezoelectric bimorphs plucked by 32 PMs through repulsive magnetic forces. The gap between PM and SM was set to 1.5 mm with a consideration on both the energy output and longevity of the bimorphs. When actuated by knee-joint motion of 0.9 Hz, the KEH produced an average power output of 5.8 mW with a life time >7.3 h (about 3.8 × 105 plucking excitations).

  14. Small footprint knife gate microvalves for large flow control

    OpenAIRE

    Braun, Stefan; Haasl, Sjoerd; Sadoon, Samir; Ridgeway, A S; van der Wijngaart, Wouter; Stemme, Göran

    2005-01-01

    This paper introduces the first area-optimized micromachined knife gate microvalve. In comparison to recent microvalves the pressure-flow performance is increased using out-of-plane actuators and an out-of-plane orifice. Three different actuator-gate designs and their fabrication are described. The valve features integrated therinal silicon/aluminum bimorph actuators where the aluminum layer forins the resistive heater as well as the bimorph material. The characterization of the actuators and...

  15. Deployable large aperture optics system for remote sensing applications.

    Energy Technology Data Exchange (ETDEWEB)

    Sumali, Anton Hartono; Martin, Jeffrey W.; Main, John A. (University of Kentucky, Lexington, KY); Macke, Benjamin T.; Massad, Jordan Elias; Chaplya, Pavel Mikhail

    2004-04-01

    This report summarizes research into effects of electron gun control on piezoelectric polyvinylidene fluoride (PVDF) structures. The experimental apparatus specific to the electron gun control of this structure is detailed, and the equipment developed for the remote examination of the bimorph surface profile is outlined. Experiments conducted to determine the optimum electron beam characteristics for control are summarized. Clearer boundaries on the bimorphs control output capabilities were determined, as was the closed loop response. Further controllability analysis of the bimorph is outlined, and the results are examined. In this research, the bimorph response was tested through a matrix of control inputs of varying current, frequency, and amplitude. Experiments also studied the response to electron gun actuation of piezoelectric bimorph thin film covered with multiple spatial regions of control. Parameter ranges that yielded predictable control under certain circumstances were determined. Research has shown that electron gun control can be used to make macrocontrol and nanocontrol adjustments for PVDF structures. The control response and hysteresis are more linear for a small range of energy levels. Current levels needed for optimum control are established, and the generalized controllability of a PVDF bimorph structure is shown.

  16. Piezoelectric Bimorphs’ Characteristics as In-Socket Sensors for Transfemoral Amputees

    Directory of Open Access Journals (Sweden)

    Amr M. El-Sayed

    2014-12-01

    Full Text Available Alternative sensory systems for the development of prosthetic knees are being increasingly highlighted nowadays, due to the rapid advancements in the field of lower limb prosthetics. This study presents the use of piezoelectric bimorphs as in-socket sensors for transfemoral amputees. An Instron machine was used in the calibration procedure and the corresponding output data were further analyzed to determine the static and dynamic characteristics of the piezoelectric bimorph. The piezoelectric bimorph showed appropriate static operating range, repeatability, hysteresis, and frequency response for application in lower prosthesis, with a force range of 0–100 N. To further validate this finding, an experiment was conducted with a single transfemoral amputee subject to measure the stump/socket pressure using the piezoelectric bimorph embedded inside the socket. The results showed that a maximum interface pressure of about 27 kPa occurred at the anterior proximal site compared to the anterior distal and posterior sites, consistent with values published in other studies. This paper highlighted the capacity of piezoelectric bimorphs to perform as in-socket sensors for transfemoral amputees. However, further experiments are recommended to be conducted with different amputees with different socket types.

  17. Magnetic field sensor using a polymer-based vibrator

    Science.gov (United States)

    Wu, Jiang; Hasebe, Kazuhiko; Mizuno, Yosuke; Tabaru, Marie; Nakamura, Kentaro

    2016-09-01

    In this technical note, a polymer-based magnetic sensor with a high resolution was devised for sensing the high magnetic field. It consisted of a bimorph (vibrator) made of poly (phenylene sulfide) (PPS) and a phosphor-bronze foil glued on the free end of the bimorph. According to Faraday’s law of induction, when a magnetic field in the direction perpendicular to the bimorph was applied, the foil cut the magnetic flux, and generated an alternating voltage across the leads at the natural frequency of the bimorph. Because PPS has low mechanical loss, low elastic modulus, and low density, high vibration velocity can be achieved if it is employed as the elastomer of the bimorph. The devised sensor was tested in the magnetic field range of 0.1-570 mT and exhibited a minimum detectable magnetic field of 0.1 mT. At a zero-to-peak driving voltage of 60 V, the sensitivity of the PPS-based magnetic sensor reached 10.5 V T-1, which was 1.36 times the value of the aluminum-based magnetic sensor with the same principle and dimensions.

  18. Increased power to weight ratio of piezoelectric energy harvesters through integration of cellular honeycomb structures

    Science.gov (United States)

    Chandrasekharan, N.; Thompson, L. L.

    2016-04-01

    The limitations posed by batteries have compelled the need to investigate energy harvesting methods to power small electronic devices that require very low operational power. Vibration based energy harvesting methods with piezoelectric transduction in particular has been shown to possess potential towards energy harvesters replacing batteries. Current piezoelectric energy harvesters exhibit considerably lower power to weight ratio or specific power when compared to batteries the harvesters seek to replace. To attain the goal of battery-less self-sustainable device operation the power to weight ratio gap between piezoelectric energy harvesters and batteries need to be bridged. In this paper the potential of integrating lightweight honeycomb structures with existing piezoelectric device configurations (bimorph) towards achieving higher specific power is investigated. It is shown in this study that at low excitation frequency ranges, replacing the solid continuous substrate of conventional bimorph with honeycomb structures of the same material results in a significant increase in power to weight ratio of the piezoelectric harvester. At higher driving frequency ranges it is shown that unlike the traditional piezoelectric bimorph with solid continuous substrate, the honeycomb substrate bimorph can preserve optimum global design parameters through manipulation of honeycomb unit cell parameters. Increased operating lifetime and design flexibility of the honeycomb core piezoelectric bimorph is demonstrated as unit cell parameters of the honeycomb structures can be manipulated to alter mass and stiffness properties of the substrate, resulting in unit cell parameter significantly influencing power generation.

  19. Magnetic field sensor using a polymer-based vibrator

    Science.gov (United States)

    Wu, Jiang; Hasebe, Kazuhiko; Mizuno, Yosuke; Tabaru, Marie; Nakamura, Kentaro

    2016-09-01

    In this technical note, a polymer-based magnetic sensor with a high resolution was devised for sensing the high magnetic field. It consisted of a bimorph (vibrator) made of poly (phenylene sulfide) (PPS) and a phosphor-bronze foil glued on the free end of the bimorph. According to Faraday’s law of induction, when a magnetic field in the direction perpendicular to the bimorph was applied, the foil cut the magnetic flux, and generated an alternating voltage across the leads at the natural frequency of the bimorph. Because PPS has low mechanical loss, low elastic modulus, and low density, high vibration velocity can be achieved if it is employed as the elastomer of the bimorph. The devised sensor was tested in the magnetic field range of 0.1–570 mT and exhibited a minimum detectable magnetic field of 0.1 mT. At a zero-to-peak driving voltage of 60 V, the sensitivity of the PPS-based magnetic sensor reached 10.5 V T‑1, which was 1.36 times the value of the aluminum-based magnetic sensor with the same principle and dimensions.

  20. Intravenous fluid flow meter concept for zero gravity environment

    Science.gov (United States)

    Miller, C. G.

    1972-01-01

    Measuring chamber, included in infusion-set tubing, and peristaltic flow meter concept can be incorporated into flow meter that measures fluid flow rates between 100 and 600 cu cm per hour and at the same time maintains sterilization.

  1. Dynamic Electromechanical Coupling of Piezoelectric Bending Actuators

    Directory of Open Access Journals (Sweden)

    Mostafa R. A. Nabawy

    2016-01-01

    Full Text Available Electromechanical coupling defines the ratio of electrical and mechanical energy exchanged during a flexure cycle of a piezoelectric actuator. This paper presents an analysis of the dynamic electromechanical coupling factor (dynamic EMCF for cantilever based piezoelectric actuators and provides for the first time explicit expressions for calculation of dynamic EMCF based on arrangement of passive and active layers, layer geometry, and active and passive materials selection. Three main cantilever layer configurations are considered: unimorph, dual layer bimorph and triple layer bimorph. The actuator is modeled using standard constitutive dynamic equations that relate deflection and charge to force and voltage. A mode shape formulation is used for the cantilever dynamics that allows the generalized mass to be the actual mass at the first resonant frequency, removing the need for numerical integration in the design process. Results are presented in the form of physical insight from the model structure and also numerical evaluations of the model to provide trends in dynamic EMCF with actuator design parameters. For given material properties of the active and passive layers and given system overall damping ratio, the triple layer bimorph topology is the best in terms of theoretically achievable dynamic EMCF, followed by the dual layer bimorph. For a damping ratio of 0.035, the dynamic EMCF for an example dual layer bimorph configuration is 9% better than for a unimorph configuration. For configurations with a passive layer, the ratio of thicknesses for the passive and active layers is the primary geometric design variable. Choice of passive layer stiffness (Young’s modulus relative to the stiffness of the material in the active layer is an important materials related design choice. For unimorph configurations, it is beneficial to use the highest stiffness possible passive material, whereas for triple layer bimorph configurations, the passive

  2. High-resolution adaptive optics scanning laser ophthalmoscope with multiple deformable mirrors

    Science.gov (United States)

    Chen, Diana C.; Olivier, Scot S.; Jones; Steven M.

    2010-02-23

    An adaptive optics scanning laser ophthalmoscopes is introduced to produce non-invasive views of the human retina. The use of dual deformable mirrors improved the dynamic range for correction of the wavefront aberrations compared with the use of the MEMS mirror alone, and improved the quality of the wavefront correction compared with the use of the bimorph mirror alone. The large-stroke bimorph deformable mirror improved the capability for axial sectioning with the confocal imaging system by providing an easier way to move the focus axially through different layers of the retina.

  3. Design, modeling, and fabrication of piezoelectric polymer actuators

    Science.gov (United States)

    Fu, Yao; Harvey, Erol C.; Ghantasala, Muralidhar K.; Spinks, Geoff

    2004-04-01

    Piezoelectric polymers are a class of materials with great potential and promise for many applications. Because of their ideally suitable characteristics, they make good candidates for actuators. However, the difficulty of forming structures and shapes has limited the range of mechanical design. In this work, the design and fabrication of a unimorph piezoelectric cantilever actuator using piezoelectric polymer PVDF with an electroplated layer of nickel alloy has been described. The modeling and simulation of the composite cantilever with planar and microstructured surfaces has been performed by CoventorWare to optimize the design parameters in order to achieve large tip deflections. These simulation results indicated that a microstructured cantilever could produce 25 percent higher deflection compared to a simple planar cantilever surface. The tip deflection of the composite cantilever with a length of 6mm and a width of 1mm can reach up to 100μm. A PVDF polymer with a specifically designed shape was punched out along the elongation direction on the embossing machine at room temperature. The nickel alloy layer was electroplated on one side of the PVDF to form a composite cantilever. The tip deflection of the cantilever was observed and measured under an optical microscope. The experimental result is in agreement with the theoretical analysis.

  4. Biocompatible circuit-breaker chip for thermal management of biomedical microsystems

    Science.gov (United States)

    Luo, Yi; Dahmardeh, Masoud; Takahata, Kenichi

    2015-05-01

    This paper presents a thermoresponsive micro circuit breaker for biomedical applications specifically targeted at electronic intelligent implants. The circuit breaker is micromachined to have a shape-memory-alloy cantilever actuator as a normally closed temperature-sensitive switch to protect the device of interest from overheating, a critical safety feature for smart implants including those that are electrothermally driven with wireless micro heaters. The device is fabricated in a size of 1.5  ×  2.0  ×  0.46 mm3 using biocompatible materials and a chip-based titanium package, exhibiting a nominal cold-state resistance of 14 Ω. The breaker rapidly enters the full open condition when the chip temperature exceeds 63 °C, temporarily breaking the circuit of interest to lower its temperature until chip temperature drops to 51 °C, at which the breaker closes the circuit to allow current to flow through it again, physically limiting the maximum temperature of the circuit. This functionality is tested in combination with a wireless resonant heater powered by radio-frequency electromagnetic radiation, demonstrating self-regulation of heater temperature. The developed circuit-breaker chip operates in a fully passive manner that removes the need for active sensor and circuitry to achieve temperature regulation in a target device, contributing to the miniaturization of biomedical microsystems including electronic smart implants where thermal management is essential.

  5. A highly aromatic and sulfonated ionomer for high elastic modulus ionic polymer membrane micro-actuators

    International Nuclear Information System (INIS)

    A high modulus, sulfonated ionomer synthesized from 4,6-bis(4-hydroxyphenyl)-N,N-diphenyl-1,3,5-triazin-2-amine and 4,4′-biphenol with bis(4-fluorophenyl)sulfone (DPA-PS:BP) is investigated for ionic polymer actuators. The uniqueness of DPA-PS:BP is that it can have a high ionic liquid (IL) uptake and consequently generates a high intrinsic strain response, which is >1.1% under 1.6 V while maintaining a high elastic modulus (i.e. 600 MPa for 65 vol% IL uptake). Moreover, such a high modulus of the active ionomer, originating from the highly aromatic backbone and side-chain-free structure, allows for the fabrication of free-standing thin film micro-actuators (down to 5 µm thickness) via the solution cast method and focused-ion-beam milling, which exhibits a much higher bending actuation, i.e. 43 µm tip displacement and 180 kPa blocking stress for a 200 µm long and 5 µm thick cantilever actuator, compared with the ionic actuators based on traditional ionomers such as Nafion, which has a much lower elastic modulus (50 MPa) and actuation strain. (paper)

  6. Biocompatible circuit-breaker chip for thermal management of biomedical microsystems

    International Nuclear Information System (INIS)

    This paper presents a thermoresponsive micro circuit breaker for biomedical applications specifically targeted at electronic intelligent implants. The circuit breaker is micromachined to have a shape-memory-alloy cantilever actuator as a normally closed temperature-sensitive switch to protect the device of interest from overheating, a critical safety feature for smart implants including those that are electrothermally driven with wireless micro heaters. The device is fabricated in a size of 1.5  ×  2.0  ×  0.46 mm3 using biocompatible materials and a chip-based titanium package, exhibiting a nominal cold-state resistance of 14 Ω. The breaker rapidly enters the full open condition when the chip temperature exceeds 63 °C, temporarily breaking the circuit of interest to lower its temperature until chip temperature drops to 51 °C, at which the breaker closes the circuit to allow current to flow through it again, physically limiting the maximum temperature of the circuit. This functionality is tested in combination with a wireless resonant heater powered by radio-frequency electromagnetic radiation, demonstrating self-regulation of heater temperature. The developed circuit-breaker chip operates in a fully passive manner that removes the need for active sensor and circuitry to achieve temperature regulation in a target device, contributing to the miniaturization of biomedical microsystems including electronic smart implants where thermal management is essential. (paper)

  7. Analysis of a piezoelectric power harvester with adjustable frequency by precise electric field method.

    Science.gov (United States)

    Wang, Yujue; Lian, Ziyang; Yao, Mingge; Wang, Ji; Hu, Hongping

    2013-10-01

    A power harvester with adjustable frequency, which consists of a hinged-hinged piezoelectric bimorph and a concentrated mass, is studied by the precise electric field method (PEFM), taking into account a distribution of the electric field over the thickness. Usually, using the equivalent electric field method (EEFM), the electric field is approximated as a constant value in the piezoelectric layer. Charge on the upper electrode (UEC) of the bimorph is often assumed as output charge. However, different output charge can be obtained by integrating on electric displacement over the electrode with different thickness coordinates. Therefore, an average charge (AC) on thickness is often assumed as the output value. This method is denoted EEFM AC. The flexural vibration of the bimorph is calculated by the three methods and their results are compared. Numerical results illustrate that EEFM UEC overestimates resonant frequency, output power, and efficiency. EEFM AC can accurately calculate the output power and efficiency, but underestimates resonant frequency. The performance of the harvester, which depends on concentrated mass weight, position, and circuit load, is analyzed using PEFM. The resonant frequency can be modulated 924 Hz by moving the concentrated mass along the bimorph. This feature suggests that the natural frequency of the harvester can be adjusted conveniently to adapt to frequency fluctuation of the ambient vibration.

  8. Multiscale optimization of saturated poroelastic actuators

    DEFF Research Database (Denmark)

    Andreasen, Casper Schousboe; Sigmund, Ole

    A multiscale method for optimizing the material micro structure in a macroscopically heterogeneous saturated poroelastic media with respect to macro properties is presented. The method is based on topology optimization using the homogenization technique, here applied to the optimization of a bi......-morph saturated poroelastic actuator....

  9. Verification of Beam Models for Ionic Polymer-Metal Composite Actuator

    Institute of Scientific and Technical Information of China (English)

    Ai-hong Ji; Hoon Cheol Park; Quoc Viet Nguyen; Jang Woo Lee; Young Tai Yoo

    2009-01-01

    Ionic Polymer-Metal Composite (IPMC) can work as an actuator by applying a few voltages. A thick IPMC actuator, where Nation-117 membrane was synthesized with polypyrrole/alumina composite tiller, was analyzed to verify the equivalent beam and equivalent bimorph beam models. The blocking force and tip displacement of the IPMC actuator were measured with a DC power supply and Young's modulus of the IPMC strip was measured by bending and tensile tests respectively. The calculated maximum tip displacement and the Young's modulus by the equivalent beam model were almost identical to the corresponding measured data. Finite element analysis with thermal analogy technique was utilized in the equivalent bimorph beam model to numerically reproduce the force-displacement relationship of the IPMC actuator. The results by the equivalent bimorph beam model agreed well with the force-displacement relationship acquired by the measured data. It is confirmed that the equivalent beam and equivalent bimorph beam models are practically and effectively suitable for predicting the tip displacement, blocking force and Young's modulus of IPMC actuators with different thickness and different composite of ionic polymer membrane.

  10. Optimisation study of micro cantilevers for switching of photonic band gap crystals

    NARCIS (Netherlands)

    Chakkalakkal Abdulla, S.; Berenschot, E.; Boer, de M.J.; Kauppinen, L.J.; Ridder, de R.M.; Krijnen, G.J.M.

    2009-01-01

    We propose to use electrostatically actuated micro bimorph cantilevers with tips for nanometric perturbations in the evanescent field of various resonators and photonic band gap crystals (PBG) using a self aligning technology. Since in PBG and in other high optical index contrast structures the inte

  11. Integrated self-aligned tips for dispersion tuning in a photonic crystal micro-cavity

    NARCIS (Netherlands)

    Abdulla, S.M.C.; Kauppinen, L.J.; Ridder, de R.M.; Krijnen, G.J.M.

    2011-01-01

    A micro-bimorph cantilever is monolithically integrated with a photonic crystal micro-cavity based device, using surface micro-machining techniques. The integrated cantilever is equipped with self-aligned dielectric tips with respect to the holes of the photonic crystal and on electrostatic actuatio

  12. Optimised Frequency Range of Active Joints for Nanometre Range Stroke

    NARCIS (Netherlands)

    Chakkalakkal Abdulla, S.M.; Krijnen, G.J.M.

    2007-01-01

    This paper describes the modelling of a micro bimorph cantilever which is composed of a Silicon Nitride cantilever beam coated on top with a thin Chromium layer. The structure functions as a vertical electrostatic actuator for nanometre displacements with stress induced upward curvature in the off-s

  13. Mechano-optical wavelength tuning in a photonic crystal microcavity with sub-1 V drive voltage

    NARCIS (Netherlands)

    Abdulla, Shahina M.C.; Kauppinen, Lasse J.; Krijnen, Gijs J.M.; Ridder, de R.M.

    2012-01-01

    A micro-bimorph cantilever with self-aligned nano-tips is monolithically integrated with a photonic crystal based device using optical and deep-UV lithography techniques. Upon electrostatic actuation, the dielectric nano-tips perturb the optical field providing electromechano-optical modulation of l

  14. Modeling and characterization of multilayered d 15 mode piezoelectric energy harvesters in series and parallel connections

    Science.gov (United States)

    Zhu, Y. K.; Yu, Y. G.; Li, L.; Jiang, T.; Wang, X. Y.; Zheng, X. J.

    2016-07-01

    A Timoshenko beam model combined with piezoelectric constitutive equations and an electrical model was proposed to describe the energy harvesting performances of multilayered d 15 mode PZT-51 piezoelectric bimorphs in series and parallel connections. The effect of different clamped conditions was considered for non-piezoelectric and piezoelectric layers in the theoretical model. The frequency dependences of output peak voltage and power at different load resistances and excitation voltages were studied theoretically, and the results were verified by finite element modeling (FEM) simulation and experimental measurements. Results show that the theoretical model considering different clamped conditions for non-piezoelectric and piezoelectric layers could make a reliable prediction for the energy harvesting performances of multilayered d 15 mode piezoelectric bimorphs. The multilayered d 15 mode piezoelectric bimorph in a series connection exhibits a higher output peak voltage and power than that of a parallel connection at a load resistance of 1 MΩ. A criterion for choosing a series or parallel connection for a multilayered d 15 mode piezoelectric bimorph is dependent on the comparison of applied load resistance with the critical resistance of about 55 kΩ. The proposed model may provide some useful guidelines for the design and performance optimization of d 15 mode piezoelectric energy harvesters.

  15. Electromechanical modeling of a honeycomb core integrated vibration energy converter with increased specific power for energy harvesting applications

    Science.gov (United States)

    Chandrasekharan, Nataraj

    Innovation in integrated circuit technology along with improved manufacturing processes has resulted in considerable reduction in power consumption of electromechanical devices. Majority of these devices are currently powered by batteries. However, the issues posed by batteries, including the need for frequent battery recharge/replacement has resulted in a compelling need for alternate energy to achieve self-sufficient device operation or to supplement battery power. Vibration based energy harvesting methods through piezoelectric transduction provides with a promising potential towards replacing or supplementing battery power source. However, current piezoelectric energy harvesters generate low specific power (power-to-weight ratio) when compared to batteries that the harvesters seek to replace or supplement. In this study, the potential of integrating lightweight cellular honeycomb structures with existing piezoelectric device configurations (bimorph) to achieve higher specific power is investigated. It is shown in this study that at low excitation frequency ranges, replacing the solid continuous substrate of a conventional piezoelectric bimorph with honeycomb structures of the same material results in a significant increase in power-to-weight ratio of the piezoelectric harvester. In order to maximize the electrical response of vibration based power harvesters, the natural frequency of these harvesters is designed to match the input driving frequency. The commonly used technique of adding a tip mass is employed to lower the natural frequency (to match driving frequency) of both, solid and honeycomb substrate bimorphs. At higher excitation frequency, the natural frequency of the traditional solid substrate bimorph can only be altered (to match driving frequency) through a change in global geometric design parameters, typically achieved by increasing the thickness of the harvester. As a result, the size of the harvester is increased and can be disadvantageous

  16. Resonance and antiresonance of symmetric and asymmetric cantilevered piezoelectric flexors.

    Science.gov (United States)

    Smits, J G; Choi, W S; Ballato, A

    1997-01-01

    The resonances of dynamically excited symmetric piezoelectric bimorphs have been determined from the equations of state. Under the effect of sinusoidal stimuli: a moment exerted at the tip M, a force exerted perpendicular to the plane of the bimorph also applied at the tip F, a uniformly applied pressure p, and an electrode voltage V, they respond with a sinusoidal tip rotation alpha, tip deflection delta, volume displacement nu, and electrode charge Q. All of the former are related to all of the latter through a dynamic admittance matrix B. The antiresonance frequency of the capacitance C have been found while also antiresonance in off-diagonal elements have been determined. The latter indicate that at these frequencies the bimorph does not work as an actuator or sensor in the particular domain of the off-diagonal. The mode shape at these antiresonance frequencies has been determined. The antiresonance of b(14) determines that for this frequency the tip has deflection but no rotation, while the antiresonance of b(24 ) indicates that the tip has rotation but no deflection. No antiresonance in the volume displacement is found, indicating that the bimorph is a pressure converter (microphone) at all frequencies. Micromachined piezoelectric heterogeneous bimorphs have been fabricated using the techniques of I.C. fabrication. Their deflections have been measured as a function of frequency and applied voltage, while these have been compared with the theoretical predictions. An anomalously large quadratic deflection has been found, superimposed on the linear piezoelectric behavior. The agreement between the linear part of the experimental deflection and the theory was quite good. PMID:18244123

  17. Bio-inspired aquatic robotics by untethered piezohydroelastic actuation.

    Science.gov (United States)

    Cen, L; Erturk, A

    2013-03-01

    This paper investigates fish-like aquatic robotics using flexible bimorphs made of macro-fiber composite (MFC) piezoelectric laminates for carangiform locomotion. In addition to noiseless and efficient actuation over a range of frequencies, geometric scalability, and simple design, bimorph propulsors made of MFCs offer a balance between the actuation force and velocity response for performance enhancement in bio-inspired swimming. The experimental component of the presented work focuses on the characterization of an elastically constrained MFC bimorph propulsor for thrust generation in quiescent water as well as the development of a robotic fish prototype combining a microcontroller and a printed-circuit-board amplifier to generate high actuation voltage for untethered locomotion. From the theoretical standpoint, a distributed-parameter electroelastic model including the hydrodynamic effects and actuator dynamics is coupled with the elongated-body theory for predicting the mean thrust in quiescent water. In-air and underwater experiments are performed to verify the incorporation of hydrodynamic effects in the linear actuation regime. For electroelastically nonlinear actuation levels, experimentally obtained underwater vibration response is coupled with the elongated-body theory to predict the thrust output. The measured mean thrust levels in quiescent water (on the order of ∼10 mN) compare favorably with thrust levels of biological fish. An untethered robotic fish prototype that employs a single bimorph fin (caudal fin) for straight swimming and turning motions is developed and tested in free locomotion. A swimming speed of 0.3 body-length/second (7.5 cm s⁻¹ swimming speed for 24.3 cm body length) is achieved at 5 Hz for a non-optimized main body-propulsor bimorph combination under a moderate actuation voltage level. PMID:23348365

  18. Rotational piezoelectric wind energy harvesting using impact-induced resonance

    Science.gov (United States)

    Yang, Ying; Shen, Qinlong; Jin, Jiamei; Wang, Yiping; Qian, Wangjie; Yuan, Dewang

    2014-08-01

    To improve the output power of a rotational piezoelectric wind energy harvester, impact-induced resonance is proposed to enable effective excitation of the piezoelectric cantilevers' vibration modes and obtain optimum deformation, which enhances the mechanical/electrical energy transformation. The impact force is introduced by forming a piezoelectric bimorph cantilever polygon that is fixed at the circumference of the rotating fan's internal surface. Elastic balls are placed inside the polygon. When wind rotates the device, the balls strike the piezoelectric cantilevers, and thus electricity is generated by the piezoelectric effect. The impact point is carefully chosen to use the first bending mode as much as possible, and thus maximize the harvesting efficiency. The design enables each bimorph to be struck in a similar area and every bimorph is struck in that area at different moments. As a result, a relatively stable output frequency can be obtained. The output frequency can also be changed by choosing different bimorph dimensions, which will also make the device simpler and the costs lower. A prototype piezoelectric energy harvester consisting of twelve piezoelectric cantilevers was constructed. The piezoelectric cantilevers were made from phosphor bronze, the lead zirconium titanate (PZT)-based bimorph cantilever had dimensions of 47 mm × 20 mm × 0.5 mm, and the elastic balls were made from steel with a diameter of 10 mm. The optimal DC output power was 613 μW across the 20 kΩ resistor at a rotation speed of 200 r/min with an inscribed circle diameter of 31 mm.

  19. Stimuli-responsive cylindrical hydrogels mimic intestinal peristalsis to propel a solid object.

    Science.gov (United States)

    Nistor, V; Cannell, J; Gregory, J; Yeghiazarian, L

    2016-04-21

    The emerging field of soft robotics relies on soft, stimuli-responsive materials to enable load transport, manipulation, and mobility in complex unconstrained environments. These materials often need to replicate biological functionality such as muscle contractions and flexibility. Here we demonstrate a soft actuator prototype based on thermosensitive PNIPAAM hydrogels that can transport and manipulate objects. A hollow cylindrical hydrogel was selectively heated and cooled with Peltier devices to yield a traveling wave of shrinking and swelling akin to intestinal peristalsis. A 4 mm diameter bead was placed inside the cylinder and propelled 19.5 mm, equal to distance traveled by the peristaltic wave. We derived conditions that enable peristaltic transport as a function of transporter-cargo design parameters. We conclude that hydrogel-based peristaltic manipulators covering 2 orders of magnitude in stiffness (1-10(2) kPa) could transport cargo spanning 4 orders of magnitude in size (μm-m).

  20. Stimuli-responsive cylindrical hydrogels mimic intestinal peristalsis to propel a solid object.

    Science.gov (United States)

    Nistor, V; Cannell, J; Gregory, J; Yeghiazarian, L

    2016-04-21

    The emerging field of soft robotics relies on soft, stimuli-responsive materials to enable load transport, manipulation, and mobility in complex unconstrained environments. These materials often need to replicate biological functionality such as muscle contractions and flexibility. Here we demonstrate a soft actuator prototype based on thermosensitive PNIPAAM hydrogels that can transport and manipulate objects. A hollow cylindrical hydrogel was selectively heated and cooled with Peltier devices to yield a traveling wave of shrinking and swelling akin to intestinal peristalsis. A 4 mm diameter bead was placed inside the cylinder and propelled 19.5 mm, equal to distance traveled by the peristaltic wave. We derived conditions that enable peristaltic transport as a function of transporter-cargo design parameters. We conclude that hydrogel-based peristaltic manipulators covering 2 orders of magnitude in stiffness (1-10(2) kPa) could transport cargo spanning 4 orders of magnitude in size (μm-m). PMID:26971454

  1. Physiological breakdown of Jeffrey six constant nanofluid flow in an endoscope with nonuniform wall

    Directory of Open Access Journals (Sweden)

    S. Nadeem

    2015-12-01

    Full Text Available This paper analyse the endoscopic effects of peristaltic nanofluid flow of Jeffrey six-constant fluid model in the presence of magnetohydrodynamics flow. The current problem is modeled in the cylindrical coordinate system and exact solutions are managed (where possible under low Reynolds number and long wave length approximation. The influence of emerging parameters on temperature and velocity profile are discussed graphically. The velocity equation is solved analytically by utilizing the homotopy perturbation technique strongly, while the exact solutions are computed from temperature equation. The obtained expressions for velocity , concentration and temperature is sketched during graphs and the collision of assorted parameters is evaluate for transform peristaltic waves. The solution depend on thermophoresis number Nt, local nanoparticles Grashof number Gr, and Brownian motion number Nb. The obtained expressions for the velocity, temperature, and nanoparticles concentration profiles are plotted and the impact of various physical parameters are investigated for different peristaltic waves.

  2. Instrumental modification intended to save time, and volumes of sample and reagent solutions, in the atomic fluorescence spectrometric determination of mercury.

    Science.gov (United States)

    Pérez-Sirvent, Carmen; Martínez-Sánchez, María J; García-Lorenzo, Mariluz; López-García, Ignacio; Hernández-Córdoba, Manuel

    2007-05-01

    Use of small membrane pumps, instead of peristaltic pumps, to introduce sample and reagent solutions into the spectrometer has several advantages in atomic fluorescence spectrometric determination of mercury. This simple modification results in a substantial saving in the time required for the measurements and so 90% of reagent solution volumes and 95% of sample solution volumes are saved, with a consequent decrease in the volume of waste generated. The sampling frequency is almost tripled, with no deterioration in sensitivity, which is similar to that obtained by use of peristaltic pumps. The relative standard deviation for ten consecutive measurements of a 1 microg L-1 mercury solution was approximately 2%. PMID:17351707

  3. Tissue engineering for neuromuscular disorders of the gastrointestinal tract

    Institute of Scientific and Technical Information of China (English)

    Kenneth L Koch; Khalil N Bitar; John E Fortunato

    2012-01-01

    The digestive tract is designed for the optimal processing of food that nourishes all organ systems.The esophagus,stomach,small bowel,and colon are sophisticated neuromuscular tubes with specialized sphincters that transport ingested food-stuffs from one region to another.Peristaltic contractions move ingested solids and liquids from the esophagus into the stomach; the stomach mixes the ingested nutrients into chyme and empties chyme from the stomach into the duodenum.The to-and-fro movement of the small bowel maximizes absorption of fat,protein,and carbohydrates.Peristaltic contractions are necessary for colon function and defecation.

  4. Increasing pumping efficiency in a micro throttle pump by enhancing displacement amplification in an elastomeric substrate

    International Nuclear Information System (INIS)

    Fluid transport is accomplished in a micro throttle pump (MTP) by alternating deformation of a micro channel cast into a polydimethylsiloxane (PDMS) elastomeric substrate. The active deformation is achieved using a bimorph PZT piezoelectric disc actuator bonded to a glass diaphragm. The bimorph PZT deflects the diaphragm as well as alternately pushing and pulling the elastomer layer providing displacement amplification in the PDMS directly surrounding the micro channel. In order to improve pumping rates we have embedded a polymethylmethacrylate (PMMA) ring into the PMDS substrate which increases the magnitude of the displacement amplification achieved. FEM simulation of the elastomeric substrate deformation predicts that the inclusion of the PMMA ring should increase the channel deformation. We experimentally demonstrate that inclusion of a PMMA ring, having a diameter equal to that of the circular node of the PZT/glass/PDMS composite, increases in the throttle resistance ratio by 40% and the maximum pumping rate by 90% compared to an MTP with no ring.

  5. Generation-X mirror technology development plan and the development of adjustable x-ray optics

    Science.gov (United States)

    Reid, Paul B.; Davis, William; O'Dell, Stephen; Schwartz, Daniel A.; Tolier-McKinstry, Susan; Wilke, Rudeger H. T.; Zhang, William

    2009-08-01

    Generation-X is being studied as an extremely high resolution, very large area grazing incidence x-ray telescope. Under a NASA Advanced Mission Concepts Study, we have developed a technology plan designed to lead to the 0.1 arcsec (HPD) resolution adjustable optics with 50 square meters of effective area necessary to meet Generation-X requirements. We describe our plan in detail. In addition, we report on our development activities of adjustable grazing incidence optics via the fabrication of bimorph mirrors. We have successfully deposited thin-film piezo-electric material on the back surface of thin glass mirrors. We report on the electrical and mechanical properties of the bimorph mirrors. We also report on initial finite element modeling of adjustable grazing incidence mirrors; in particular, we examine the impact of how the mirrors are supported - the boundary conditions - on the deformations which can be achieved.

  6. Underwater propulsion of an internally actuated elastic plate

    Science.gov (United States)

    Yeh, Peter; Cen, Lejun; Erturk, Alper; Alexeev, Alexander

    2013-03-01

    Combining experiments and numerical simulations we examine underwater locomotion of an active (internally powered) flexible bimorph composite. We use Macro-Fiber Composite (MFC) piezoelectric laminates that are actuated by a sinusoidally varying voltage generating thrust similar to that of a flapping fin in carangiform motion. In our fully-coupled three dimensional simulations, we model this MFC bimorph fin as a thin, elastic plate that is actuated by a time-varying internal moment producing periodic fin bending and oscillations. The steady state swim velocity and thrust are experimentally measured and compared to the theoretical predictions. Our simulations provide detailed information about the flow structures around the swimming fin and show how they affect the forward motion. The results are useful for designing self-propelling fish-like robots driven by internally powered fins.

  7. Torque for an Inertial Piezoelectric Rotary Motor

    Directory of Open Access Journals (Sweden)

    Jichun Xing

    2013-01-01

    Full Text Available For a novel inertial piezoelectric rotary motor, the equation of the strain energy in the piezoceramic bimorph and the equations of the strain energy and the kinetic energy in the rotor are given. Based on them, the dynamic equation of the motor is obtained. Using these equations, the inertial driving torque of the motor is investigated. The results show that the impulsive driving torque changes with changing peak voltage of the excitation signal, the piezoelectric stress constant, the thickness of the piezoceramic bimorph, and the rotor radius obviously. Tests about the motor torque are completed which verifies the theory analysis here in. The results can be used to design the operating performance of the motor.

  8. Two-dimensional in situ metrology of X-ray mirrors using the speckle scanning technique

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hongchang, E-mail: hongchang.wang@diamond.ac.uk; Kashyap, Yogesh; Laundy, David; Sawhney, Kawal [Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot OX11 0DE (United Kingdom)

    2015-06-06

    The two-dimensional slope error of an X-ray mirror has been retrieved by employing the speckle scanning technique, which will be valuable at synchrotron radiation facilities and in astronomical telescopes. In situ metrology overcomes many of the limitations of existing metrology techniques and is capable of exceeding the performance of present-day optics. A novel technique for precisely characterizing an X-ray bimorph mirror and deducing its two-dimensional (2D) slope error map is presented. This technique has also been used to perform fast optimization of a bimorph mirror using the derived 2D piezo response functions. The measured focused beam size was significantly reduced after the optimization, and the slope error map was then verified by using geometrical optics to simulate the focused beam profile. This proposed technique is expected to be valuable for in situ metrology of X-ray mirrors at synchrotron radiation facilities and in astronomical telescopes.

  9. Two-dimensional in situ metrology of X-ray mirrors using the speckle scanning technique.

    Science.gov (United States)

    Wang, Hongchang; Kashyap, Yogesh; Laundy, David; Sawhney, Kawal

    2015-07-01

    In situ metrology overcomes many of the limitations of existing metrology techniques and is capable of exceeding the performance of present-day optics. A novel technique for precisely characterizing an X-ray bimorph mirror and deducing its two-dimensional (2D) slope error map is presented. This technique has also been used to perform fast optimization of a bimorph mirror using the derived 2D piezo response functions. The measured focused beam size was significantly reduced after the optimization, and the slope error map was then verified by using geometrical optics to simulate the focused beam profile. This proposed technique is expected to be valuable for in situ metrology of X-ray mirrors at synchrotron radiation facilities and in astronomical telescopes.

  10. Increasing pumping efficiency in a micro throttle pump by enhancing displacement amplification in an elastomeric substrate

    Science.gov (United States)

    Fujiwara, T.; Johnston, I. D.; Tracey, M. C.; Tan, C. K. L.

    2010-06-01

    Fluid transport is accomplished in a micro throttle pump (MTP) by alternating deformation of a micro channel cast into a polydimethylsiloxane (PDMS) elastomeric substrate. The active deformation is achieved using a bimorph PZT piezoelectric disc actuator bonded to a glass diaphragm. The bimorph PZT deflects the diaphragm as well as alternately pushing and pulling the elastomer layer providing displacement amplification in the PDMS directly surrounding the micro channel. In order to improve pumping rates we have embedded a polymethylmethacrylate (PMMA) ring into the PMDS substrate which increases the magnitude of the displacement amplification achieved. FEM simulation of the elastomeric substrate deformation predicts that the inclusion of the PMMA ring should increase the channel deformation. We experimentally demonstrate that inclusion of a PMMA ring, having a diameter equal to that of the circular node of the PZT/glass/PDMS composite, increases in the throttle resistance ratio by 40% and the maximum pumping rate by 90% compared to an MTP with no ring.

  11. Micro scanning probes

    CERN Document Server

    Niblock, T

    2001-01-01

    This thesis covers the design methodology, theory, modelling, fabrication and evaluation of a Micro-Scanning-Probe. The device is a thermally actuated bimorph quadrapod fabricated using Micro Electro Mechanical Systems technology. A quadrapod is a structure with four arms, in this case a planar structure with the four arms forming a cross which is dry etched out of a silicon diaphragm. Each arm has a layer of aluminium deposited on it forming a bimorph. Through heating each arm actuation is achieved in the plane of the quadrapod and the direction normal to it. Fabrication of the device has required the development of bulk micromachining techniques to handle post CMOS fabricated wafers and the patterning of thickly sputtered aluminium in bulk micro machined cavities. CMOS fabrication techniques were used to incorporate diodes onto the quadrapod arms for temperature measurement of the arms. Fine tungsten and silicon tips have also been fabricated to allow tunnelling between the tip and the platform at the centr...

  12. Millipede-inspired locomotion through novel U-shaped piezoelectric motors

    International Nuclear Information System (INIS)

    We report a novel piezoelectric motor that operates at a resonance frequency of 144 Hz, much lower than that of conventional ultrasonic motors, and meets the displacement and gait requirements for designing the locomotion mechanism of a millipede-inspired robot (millibot). The motor structure consists of two piezoelectric bimorphs arranged in a U-shaped configuration. Using the first bending mode for both the piezoelectric bimorphs an elliptical motion was obtained at the tip which led to the successful implementation of millipede inspired locomotion. At an input voltage of 70.7 Vrms, the piezoelectric motor operating at resonance frequency was able to generate torque of 0.03 mN m, mechanical power of 0.84 mW and maximum velocity of 62 rad s−1. Detailed discussion is provided about the principle of operation of the millibot. (technical note)

  13. Design and experimental evaluation of flextensional-cantilever based piezoelectric transducers for flow energy harvesting

    Science.gov (United States)

    Lee, Hyeong Jae; Sherrit, Stewart; Tosi, Luis Phillipe; Colonius, Tim

    2016-04-01

    Cantilever type piezoelectric harvesters, such as bimorphs, are typically used for vibration induced energy harvesting. However, a major drawback of a piezoelectric bimorph is its brittle nature in harsh environments, precipitating short life-times as well as output power degradation. The emphasis in this work is to design robust, highly efficient piezoelectric harvesters that are capable of generating electrical power in the milliwatt range. Various harvesters were modeled, designed and prototyped, and the flextensional actuator based harvester, where the metal cantilever is mounted and coupled between two flextensional actuators, was found to be a viable alternative to the cantilever type piezoelectric harvesters. Preliminary tests show that these devices equipped with 5x5x36 mm two piezoelectric PZT stacks can produce greater than 50 mW of power under air flow induced vibrations.

  14. Design and Simulation of Array of Rectangular Micro Cantilevers Piezoelectric Energy Harvester

    Directory of Open Access Journals (Sweden)

    Komal Kumari

    2016-09-01

    Full Text Available This paper presents the design, analysis and simulation of MEMS based array of bimorph rectangular microcantilever piezoelectric energy harvester structure with and without tip mass, to analyze their sensitivity. The microcantilever beams are made up of piezoelectric material and Aluminium as a substrate material. The analytical simulation of design is done by FEM (COMSOL Multiphysics. The simulation results of bimorph cantilever structure, applied force of 0.1 N and obtained end displacement and electric potential developed are given. The analytical model of the cantilever beam will be analyzed and the process of its construction will be discussed. The changes in the sensitivity of a cantilever beam with respect to change in its shape for the same applied force of 0.1N are denoted.

  15. Modeling and Analysis of a Piezoelectric Energy Harvester with Varying Cross-Sectional Area

    Directory of Open Access Journals (Sweden)

    Maiara Rosa

    2014-01-01

    Full Text Available This paper reports on the modeling and on the experimental verification of electromechanically coupled beams with varying cross-sectional area for piezoelectric energy harvesting. The governing equations are formulated using the Rayleigh-Ritz method and Euler-Bernoulli assumptions. A load resistance is considered in the electrical domain for the estimate of the electric power output of each geometric configuration. The model is first verified against the analytical results for a rectangular bimorph with tip mass reported in the literature. The experimental verification of the model is also reported for a tapered bimorph cantilever with tip mass. The effects of varying cross-sectional area and tip mass on the electromechanical behavior of piezoelectric energy harvesters are also discussed. An issue related to the estimation of the optimal load resistance (that gives the maximum power output on beam shape optimization problems is also discussed.

  16. Reconfiguring photonic metamaterials with currents and magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Valente, João, E-mail: jpv1f11@orc.soton.ac.uk; Ou, Jun-Yu; Plum, Eric, E-mail: erp@orc.soton.ac.uk [Optoelectronics Research Centre and Centre for Photonic Metamaterials, University of Southampton, Southampton SO17 1BJ (United Kingdom); Youngs, Ian J. [Physical Sciences Department, DSTL, Salisbury SP4 0JQ (United Kingdom); Zheludev, Nikolay I., E-mail: niz@orc.soton.ac.uk [Optoelectronics Research Centre and Centre for Photonic Metamaterials, University of Southampton, Southampton SO17 1BJ (United Kingdom); Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore 637378 (Singapore)

    2015-03-16

    We demonstrate that spatial arrangement and optical properties of metamaterial nanostructures can be controlled dynamically using currents and magnetic fields. Mechanical deformation of metamaterial arrays is driven by both resistive heating of bimorph nanostructures and the Lorentz force that acts on charges moving in a magnetic field. With electrically controlled transmission changes of up to 50% at sub-mW power levels, our approaches offer high contrast solutions for dynamic control of metamaterial functionalities in optoelectronic devices.

  17. Tactile Displays with Parallel Mechanism

    OpenAIRE

    Kyung, Ki-Uk; Kwon, Dong-Soo

    2008-01-01

    This chapter deals with tactile displays and their mechanisms. We briefly reviewed research history of mechanical type tactile displays and their parallel arrangement. And this chapter mainly describes two systems including tactile displays. The 5x6 pin arrayed tactile display with parallel arrangement of piezoelectric bimorphs has been described in the section 3. The tactile display has been embedded into a mouse device and the performance of the device has been verified from pattern display...

  18. Application of PGD on parametric modeling of a piezoelectric energy harvester

    OpenAIRE

    Qin, Zhi; Talleb, Hakeim; Yan, Shuai; Xu, Xiaoyu; Ren, Zhuoxiang

    2016-01-01

    International audience; In this paper, a priori model reduction methods via low-rank tensor approximation are introduced for the parametric study of a piezoelectric energy harvester (EH). The EH, comprised of a cantilevered piezoelectric bimorph connected with electrical loads, is modeled using three dimensional finite elements (FEs). Solving the model for various excitation frequencies and electrical load using the conventional approach results in a large size problem that is costly in terms...

  19. Integration of Energy Harvester for Self-Powered Wireless Sensor Network Nodes

    OpenAIRE

    Lijuan Chen; Xiaohui Xu; Pingliang Zeng; Jianqiang Ma

    2014-01-01

    This paper reports an energy harvester suitable for self-powered wireless sensor network (WSN) nodes consisting of a piezoelectric cantilever, an energy harvesting circuit, and a storage capacitor. Having the same size as a credit card, the proposed WSN nodes can be easily integrated into various applications, such as motor and air conditioning equipment. The WSN node is powered by an integrated bimorph piezoelectric generator that harvests energy from ambient vibration. The paper has develop...

  20. On-line monitoring of Glucose and penicillin by sequential injection analysis

    DEFF Research Database (Denmark)

    Min, R.W.; Nielsen, Jens Bredal; Villadsen, John

    1996-01-01

    A sequential injection analysis (SIA) system has been developed for on-line monitoring of glucose and penicillin during cultivations of the filamentous fungus Penicillium chrysogenum. The SIA system consists of a peristaltic pump, an injection valve, two piston pumps, two multi-position valves...

  1. Effect of esophageal emptying and saliva on clearance of acid from the esophagus

    International Nuclear Information System (INIS)

    The clearance of acid from the esophagus and esophageal emptying in normal subjects was studied. A 15-ml bolus of 0.1 N hydrochloric acid (pH 1.2) radiolabeled with [/sup 99m/Tc]sulfur colloid was injected into the esophagus, and the subject swallowed every 30 seconds. Concurrent manometry and radionuclide imaging showed nearly complete emptying of acid from the esophagus by an immediate secondary peristaltic sequence, although esophageal pH did not rise until the first swallow 30 seconds later. Esophageal pH then returned to normal by a series of step increases, each associated with a swallow-induced peristaltic sequence. Saliva stimulation by an oral lozenge shortened the time required for acid clearance, whereas aspiration of saliva from the mouth abolished acid clearance. Saliva stimulation or aspiration did not affect the virtually complete emptying of acid volume by the initial peristaltic sequence. It was concluded that esophageal acid clearance normally occurs as a two-step process: (1) Virtually all acid volume is emptied from the esophagus by one or two peristaltic sequences, leaving a minimal residual amount that sustains a low pH, and (2) residual acid is neutralized by swallowed saliva

  2. Protein interactions at the heart of cardiac chamber formation

    NARCIS (Netherlands)

    C.J.J. Boogerd; A.F.M. Moorman; P. Barnett

    2009-01-01

    The vertebrate heart is a muscular pump that contracts in a rhythmic fashion to propel the blood through the body. During evolution, the morphologically complex four-chambered heart of birds and mammals has evolved from a single-layered tube with peristaltic contractility. The heart of Drosophila, r

  3. Long wavelength flow analysis in a curved channel

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Nasir [Dept. of Mathematics, International Islamic Univ., Islamabad (Pakistan); Sajid, Muhammad [Theoretical Plasma Physics Div., PINSTECH, P.O. Nilore, Islamabad (Pakistan); Hayat, Tasawar [Dept. of Mathematics, Quaid-i-Azam Univ., Islamabad (Pakistan)

    2010-03-15

    This study is concerned with the peristaltic flow of a viscous fluid in a curved channel. Mathematically the problem is governed by two partial differential equations. Closed form solutions of the stream function, axial velocity, and pressure gradient are developed under long wavelength and low Reynolds number assumptions. The influence of curvature is analyzed on various flow quantities of interest. (orig.)

  4. Application of a dynamic in vitro gastrointestinal tract model to study the availability of food mutagens, using heterocyclic aromatic amines as model compounds

    NARCIS (Netherlands)

    Krul, C.A.M.; Luiten-Schuite, A.; Baan, R.; Verhagen, H.; Mohn, G.; Feron, V.; Havenaar, R.

    2000-01-01

    The TNO gastro-Intestinal tract Model (TIM) is a dynamic computer-controlled in vitro system that mimics the human physiological conditions in the stomach and small intestine. In the current TIM physiological parameters such as pH, temperature, peristaltic movements, secretion of digestion enzymes,

  5. MR urography (MRU of non-dilated ureter with diuretic administration: Static fluid 2D FSE T2-weighted versus 3D gadolinium T1-weighted GE excretory MR

    Directory of Open Access Journals (Sweden)

    C. Roy

    2014-01-01

    Conclusion: T2-weighted MRU with multiple orientations and diuretic is sufficient to identify the non-dilated ureter. It offers information on ureteral peristaltism. It can be suggested that this sequence is able to detect an initial obstruction before hydronephrosis occurs.

  6. Pharmacologic Agents for Chronic Diarrhea

    OpenAIRE

    Lee, Kwang Jae

    2015-01-01

    Chronic diarrhea is usually associated with a number of non-infectious causes. When definitive treatment is unavailable, symptomatic drug therapy is indicated. Pharmacologic agents for chronic diarrhea include loperamide, 5-hydroxytryptamine type 3 (5-HT3) receptor antagonists, diosmectite, cholestyramine, probiotics, antispasmodics, rifaximin, and anti-inflammatory agents. Loperamide, a synthetic opiate agonist, decreases peristaltic activity and inhibits secretion, resulting in the reductio...

  7. Continuous venovenous haemodialysis

    DEFF Research Database (Denmark)

    Bistrup, C; Pedersen, R S; Jensen, Dorte Møller

    1996-01-01

    A simple three-pump-based system for the performance of continuous venovenous haemodialysis is described. The method employs access to the circulation via a double-lumen catheter, and by means of a standard extracorporeal peristaltic pump the blood is circulated through a haemofiltration filter. ...

  8. Gastric pH distribution and mixing of soft and rigid food particles in the stomach using a dual-marker technique

    Science.gov (United States)

    Mixing of a particle-laden material during peristaltic flow in the stomach has not been quantified in vivo. Gastric mixing plays a key role in the overall gastric digestion process; it determines the availability of acid and enzymes to individual solid food particles and controls the length of time ...

  9. Design and verification of a smart wing for an extreme-agility micro-air-vehicle

    International Nuclear Information System (INIS)

    A special class of fixed-wing micro-air-vehicle (MAV) is currently being designed to fly and hover to provide range superiority as well as being able to hover through a flight maneuver known as prop-hanging to accomplish a variety of surveillance missions. The hover maneuver requires roll control of the wing through differential aileron deflection but a conventional system contributes significantly to the gross weight and complexity of a MAV. Therefore, it is advantageous to use smart structure approaches with active materials to design a lightweight, robust wing for the MAV. The proposed smart wing consists of an active trailing edge flap integrated with bimorph actuators with piezoceramic fibers. Actuation is enhanced by preloading the bimorph actuators with a compressive axial load. The preload is exerted on the actuators through a passive latex or electroactive polymer (EAP) skin that wraps around the airfoil. An EAP skin would further enhance the actuation by providing an electrostatic effect of the dielectric polymer to increase the deflection. Analytical modeling as well as finite element analysis show that the proposed concept could achieve the target bi-directional deflection of 30° in typical flight conditions. Several bimorph actuators were manufactured and an experimental setup was designed to measure the static and dynamic deflections. The experimental results validated the analytical technique and finite element models, which have been further used to predict the performance of the smart wing design for a MAV

  10. Design and verification of a smart wing for an extreme-agility micro-air-vehicle

    Science.gov (United States)

    Wickramasinghe, Viresh; Chen, Yong; Martinez, Marcias; Wong, Franklin; Kernaghan, Robert

    2011-12-01

    A special class of fixed-wing micro-air-vehicle (MAV) is currently being designed to fly and hover to provide range superiority as well as being able to hover through a flight maneuver known as prop-hanging to accomplish a variety of surveillance missions. The hover maneuver requires roll control of the wing through differential aileron deflection but a conventional system contributes significantly to the gross weight and complexity of a MAV. Therefore, it is advantageous to use smart structure approaches with active materials to design a lightweight, robust wing for the MAV. The proposed smart wing consists of an active trailing edge flap integrated with bimorph actuators with piezoceramic fibers. Actuation is enhanced by preloading the bimorph actuators with a compressive axial load. The preload is exerted on the actuators through a passive latex or electroactive polymer (EAP) skin that wraps around the airfoil. An EAP skin would further enhance the actuation by providing an electrostatic effect of the dielectric polymer to increase the deflection. Analytical modeling as well as finite element analysis show that the proposed concept could achieve the target bi-directional deflection of 30° in typical flight conditions. Several bimorph actuators were manufactured and an experimental setup was designed to measure the static and dynamic deflections. The experimental results validated the analytical technique and finite element models, which have been further used to predict the performance of the smart wing design for a MAV.

  11. Comparing theory with experimental data in studying the deformation of magnetically smart films deposited on nickel and glass substrates

    Science.gov (United States)

    Wang, Xiaoli; Cao, Jian; Ulmer, M. P.; Graham, M. E.; Vaynman, S.; Savoie, J.; Bellavia, B.

    2012-10-01

    This paper will present the procedure of measuring the deformation of the magnetostrictive bimorph specimens under an applied external magnetic field, and the theoretical and numerical analysis of the deformation. The magnetically smart material (MSM) KelvinAllTM and Terfenol-D is deposited on the nickel or glass substrates. The profiles of thin-film specimens were measured under an external magnetic field with White Light Interferometry. Using the theoretical calculation, the magnetostrictive property was evaluated for the coated Ni sample and glass sample. Employing the numerical approach, the influence of the magnetostrictive film on the deformation of the sample was simulated and compared with experimental results. The coated Ni specimen exhibited larger deformation than the coated glass specimen when the specimen is immersed in a 0.16 T magnetic field. In our experiments, the residual stress calculated in the thin film of the bimorph is acceptable and could be decreased by changing the parameters in the specimen preparation process. The experimental results in this paper was employed as the preliminary step to realize the future application of the magnetostrictive thin film bimorph to the adaptive X-ray mirror, and the theoretical and numerical approach was used to predict the influence of the magnetostrictive film on the larger mirror surface deformation.

  12. The pizzicato knee-joint energy harvester: characterization with biomechanical data and the effect of backpack load

    Science.gov (United States)

    Pozzi, Michele; Aung, Min S. H.; Zhu, Meiling; Jones, Richard K.; Goulermas, John Y.

    2012-07-01

    The reduced power requirements of miniaturized electronics offer the opportunity to create devices which rely on energy harvesters for their power supply. In the case of wearable devices, human-based piezoelectric energy harvesting is particularly difficult due to the mismatch between the low frequency of human activities and the high-frequency requirements of piezoelectric transducers. We propose a piezoelectric energy harvester, to be worn on the knee-joint, that relies on the plucking technique to achieve frequency up-conversion. During a plucking action, a piezoelectric bimorph is deflected by a plectrum; when released due to loss of contact, the bimorph is free to vibrate at its resonant frequency, generating electrical energy with the highest efficiency. A prototype, featuring four PZT-5H bimorphs, was built and is here studied in a knee simulator which reproduces the gait of a human subject. Biomechanical data were collected with a marker-based motion capture system while the subject was carrying a selection of backpack loads. The paper focuses on the energy generation of the harvester and how this is affected by the backpack load. By altering the gait, the backpack load has a measurable effect on performance: at the highest load of 24 kg, a minor reduction in energy generation (7%) was observed and the output power is reduced by 10%. Both are so moderate to be practically unimportant. The average power output of the prototype is 2.06 ± 0.3 mW, which can increase significantly with further optimization.

  13. Piezoelectric energy harvesting in internal fluid flow.

    Science.gov (United States)

    Lee, Hyeong Jae; Sherrit, Stewart; Tosi, Luis Phillipe; Walkemeyer, Phillip; Colonius, Tim

    2015-01-01

    We consider piezoelectric flow energy harvesting in an internal flow environment with the ultimate goal powering systems such as sensors in deep oil well applications. Fluid motion is coupled to structural vibration via a cantilever beam placed in a converging-diverging flow channel. Two designs were considered for the electromechanical coupling: first; the cantilever itself is a piezoelectric bimorph; second; the cantilever is mounted on a pair of flextensional actuators. We experimentally investigated varying the geometry of the flow passage and the flow rate. Experimental results revealed that the power generated from both designs was similar; producing as much as 20 mW at a flow rate of 20 L/min. The bimorph designs were prone to failure at the extremes of flow rates tested. Finite element analysis (FEA) showed fatigue failure was imminent due to stress concentrations near the bimorph's clamped region; and that robustness could be improved with a stepped-joint mounting design. A similar FEA model showed the flextensional-based harvester had a resonant frequency of around 375 Hz and an electromechanical coupling of 0.23 between the cantilever and flextensional actuators in a vacuum. These values; along with the power levels demonstrated; are significant steps toward building a system design that can eventually deliver power in the Watts range to devices down within a well. PMID:26473879

  14. A spiral-shaped harvester with an improved harvesting element and an adaptive storage circuit.

    Science.gov (United States)

    Hu, Hongping; Xue, Huan; Hu, Yuantai

    2007-06-01

    A piezoelectric energy harvester consists of a spiral-shaped piezoelectric bimorph to transfer mechanical energy into electric energy, an electrochemical battery to store the scavenged electric energy, and a rectifier together with a step-down dc-dc converter to connect the two components as an integrated system. A spiral-shaped harvesting structure is studied in this paper because it is very useful in the microminiaturization of advanced sensing technology. The aim of employing a step-down dc-dc converter in the storage circuit is to match the optimal output voltage of the piezoelectric bimorph with the battery voltage for efficient charging. In order to raise the output power density of a harvesting element, moreover, we apply a synchronized switch harvesting on inductor (SSHI) in parallel with the piezoelectric bimorph to artificially extend the closed-circuit interval of the rectifier. Numerical results show that the introduction of a dc-dc converter in the storage circuit or a SSHI in the harvesting structure can raise the charging efficiency several times higher than a harvester without a dc-dc converter or an SSHI. PMID:17571816

  15. Effect of mixing on reaction-diffusion kinetics for protein hydrogel-based microchips.

    Science.gov (United States)

    Zubtsov, D A; Ivanov, S M; Rubina, A Yu; Dementieva, E I; Chechetkin, V R; Zasedatelev, A S

    2006-03-01

    Protein hydrogel-based microchips are being developed for high-throughput evaluation of the concentrations and activities of various proteins. To shorten the time of analysis, the reaction-diffusion kinetics on gel microchips should be accelerated. Here we present the results of the experimental and theoretical analysis of the reaction-diffusion kinetics enforced by mixing with peristaltic pump. The experiments were carried out on gel-based protein microchips with immobilized antibodies under the conditions utilized for on-chip immunoassay. The dependence of fluorescence signals at saturation and corresponding saturation times on the concentrations of immobilized antibodies and antigen in solution proved to be in good agreement with theoretical predictions. It is shown that the enhancement of transport with peristaltic pump results in more than five-fold acceleration of binding kinetics. Our results suggest useful criteria for the optimal conditions for assays on gel microchips to balance high sensitivity and rapid fluorescence saturation kinetics.

  16. Second sound in bursting freely suspended smectic-A films.

    Science.gov (United States)

    Müller, Frank; Bohley, Christian; Stannarius, Ralf

    2009-04-01

    We describe the bursting of macroscopic spherical bubbles formed by smectic liquid crystals. During rupture, strong light scattering is observed. It is suggested here that peristaltic undulations of the films are responsible for this scattering. This phenomenon distinguishes bursting smectic films from bursting soap films. The dynamics of these mechanical waves are strongly influenced by the internal layered structure of the smectic films, viz. by the elasticity of the molecular layers, expressed by the smectic layer compression modulus B. We study experimentally the optical properties of bursting smectic films by means of optical transmission measurements and laser scattering. The typical wavelength range of the propagating peristaltic waves is in the micrometer range. The wavelength spectrum rather is independent of the initial film thickness delta, but the scattering intensity strongly depends on delta. PMID:19518341

  17. A kinematic study of pulsation in the dorsal blood vessel of the blackworm, Lumbriculus variegatus

    Directory of Open Access Journals (Sweden)

    Kameko Halfmann

    2011-01-01

    Full Text Available The aquatic oligochaete Lumbriculus variegatus has a segmented, dorsal blood vessel (DBV that acts as a peristaltic pump to move blood through the animal's closed circulatory system. We conducted a kinematic study using videography and computational modeling as a first step toward understanding the control of DBV pulsation. Results suggested that pulse rates were highest in the posterior segments, while interpulse intervals and intersegmental delays were longest in the midbody segments. Differences in the interpulse interval distributions across regions suggest that some peristaltic waves initiated in the posterior segments do not propagate all the way to the anterior segments. A simple model consisting of a chain of excitable neuromuscular units replicated these kinetics. This model may be useful in future research aimed at understanding the modulatory effect of biogenic amines on peristalsis of the DBV. Moreover, research into the mechanisms of peristalsis of the DBV may lead to insights into disorders of peristalsis in human and veterinary medicine

  18. The role of prostaglandines in peristalsis of the human colon.

    Science.gov (United States)

    Bruch, H P; Schmidt, E; Laven, R; Kehrer, G; Wasner, K H

    1978-08-01

    Prostaglandines (PG) of the E and F series cause peristaltic activity in isolated longitudinal muscle strips of the human colon. As this phasic motor reaction can be varied by acetyl choline and adrenaline it was supposed, that prostaglandines contribute to peristalsis. The role of PG E and F in the human colon was studied by inhibiting the prostaglandine synthesis and by antagonizing the prostaglandine-effects. Indomethacin proved to be a suitable inhibitor. HR 546 was found a powerful antagonist. The effect of Pentagastrin and Cholecystokinin (CCK) on peristaltic activity were suppressed by Indomethacin and HR 546. The inhibition of peristalsis by Indomethacin and HR 546 was removed by high doses of PG E and F. On the basis of these results the role of PG for the motility of the gut is discussed.

  19. Deformation Analysis of a Pneumatically-Activated Polydimethylsiloxane (PDMS Membrane and Potential Micro-Pump Applications

    Directory of Open Access Journals (Sweden)

    Chi-Han Chiou

    2015-01-01

    Full Text Available This study presents a double-side diaphragm peristaltic pump for efficient medium transport without the unwanted backflow and the lagging effect of a diaphragm. A theoretical model was derived to predict the important parameter of the micropump, i.e., the motion of the valves at large deformations, for a variety of air pressures. Accordingly, we proposed an easy and robust design to fabricate a Polydimethylsiloxane (PDMS-based micropump. The theoretical model agrees with a numerical model and experimental data for the deformations of the PDMS membrane. Furthermore, variations of the generated flow rate, including pneumatic frequencies, actuated air pressures, and operation modes were evaluated experimentally for the proposed micropumps. In future, the theoretical equation could provide the optimal parameters for the scientists working on the fabrication of the diaphragm peristaltic pump for applications of cell-culture.

  20. Study of the Gastric Emptying in Humans: Biomagnetic Assessments

    Science.gov (United States)

    Hernández, E.; Córdova, T.; Huerta-Franco, R.; Sosa, M.; Vargas-Luna, M.

    2006-09-01

    Biomagnetic studies of the gastrointestinal system can be carried out in two ways. Recording the magnetic field produced by the myenteric nervous system or created by any oral contrast mean as magnetic tracers or markers. In the first case, a SQUID magnetometer is demanded while a fluxgate magnetometer is enough in the second case. In this work, a magnetic marker was ingested by 8 healthy volunteers, in three gastric volume conditions, to measure the luminal content volume effect in the gastric emptying and to perform the quantification of the peristaltic frequencies in gastric and duodenum tract segments. The average emptying times for low luminal content, relative to the emptying time when the intake was the highest, were 43.6 ± 15.6 % and 77.3 ± 47.0 %. These results show that the biomagnetic technique is a powerful modality to estimate the effects of the gastric volume in the gastric emptying and a way to record the peristaltic frequencies.

  1. A mathematical model of motorneuron dynamics in the heartbeat of the leech

    Science.gov (United States)

    Buono, Pietro-Luciano; Palacios, A.

    2004-02-01

    The heartbeat of the medicinal leech is driven by direct contact between two arrays of motorneurons and two lateral blood vessels. At any given time, motorneurons exhibit one of two alternating states so that, on one side of the animal, the heart beats in a rear-to-front fashion (peristaltic), while on the other side the heart beats synchronously. Every 20 heartbeats, approximately, the two sides switch modes. It is known that the heartbeat rhythm is generated through burst of oscillatory activity produced by a central pattern generator (CPG) network of neurons. However, to the best of our knowledge, how the CPG activity is translated into peristaltic and synchronous rhythms in the motorneurons is yet unknown. In this work, we use symmetric systems of differential equations, accompanied with computational simulations, to investigate possible mechanisms for generating the motorneuron activity that characterizes the heartbeat of leeches and in particular the switching scenario.

  2. 基于1×2阵列压电悬臂梁的AFM并行扫描%Parallel Scanning of AFM Based on the 1×2 Array Cantilever

    Institute of Scientific and Technical Information of China (English)

    林旭东; 董维杰

    2011-01-01

    分析了阵列悬臂探针并行扫描的工作方式,以非接触磁力模拟样品与悬臂梁间的范德华力,研究了1×2阵列压电悬臂梁的并行扫描和驱动控制方法.每一压电梁均集成了微位移致动器和力传感器,在320 Hz一阶共振频率下振动.实验表明:在0.2~1.0 mm力作用区内,压电梁自由端每接近模拟样品0.1 mm,表征悬臂梁振幅的锁相放大器输出电压减小1.7 mV,但微力传感在扫描的升回程存在迟滞;致动器的控制电压每增加10 V使锁相放大器输出减小约3 mV,表明集成的致动器可调节压电梁与样品间的间距.两压电梁的电荷-位移响应曲线、间距调节灵敏度均不完全一致,讨论了阵列悬臂梁一致性问题和阵列规模大小问题.%The operation way of the parallel scanning using array cantilevers in AFM was analyzed. The non-contact magnetic force was used to imitate van der Waals forces between the sample and the cantilever, and the 1 × 2 array piezoelectric bimorph was taken for example to investigate the parallel scanning and the drive control method. Each piezoelectric bimorph was integrated with both the micrometric displacement actuator and force sensor, and the array bimorph were excited by a vibration exciter at the first resonance of 320 Hz. The charge response to the magnetic force was detected by the charge amplifier and lock-in amplifier. The experimental results show that the lock-in amplifier output decreases 1.7 mV as the bimorph approaches each 0.1 mm to the sample in 0. 2 - 1.0 mm force function range, however the force sensor shows the hysteresis in a round trip. lhe lock-in amplifier output reduces about 3 mV for every 10 V increase in the actuation voltage, which indicates that the distance between the sample and the cantilever can be independently adjusted by each bimorph. It is not ideal that the sensitivity of the charge displacement response curves and the distance adjustment for the two bimorph are

  3. Slime mould electronic oscillators

    OpenAIRE

    Adamatzky, Andrew

    2014-01-01

    We construct electronic oscillator from acellular slime mould Physarum polycephalum. The slime mould oscillator is made of two electrodes connected by a protoplasmic tube of the living slime mould. A protoplasmic tube has an average resistance of 3~MOhm. The tube's resistance is changing over time due to peristaltic contractile activity of the tube. The resistance of the protoplasmic tube oscillates with average period of 73~sec and average amplitude of 0.6~MOhm. We present experimental labor...

  4. Frequency Behavior of a Quartz Crystal Microbalance (Qcm) in Contact with Selected Solutions

    OpenAIRE

    Z. A. Talib; Z. Baba; Kurosawa, S.; H. A.A. Sidek; A. Kassimb; W. M.M. Yunus

    2006-01-01

    A device was constructed to monitor viscosity of solutions using fundamental frequency of 9 MHz and 10 MHz quartz crystal. Piezoelectric quartz crystals with gold electrodes were mounted by O-ring in between liquid flow cell. Only one side of the crystal was exposed to the solutions which were pumped through silicon tube by a peristaltic pump. The measured frequency shift was observed in order to investigate the interfacial behavior of some selected solution in contact with one surface of Qua...

  5. Effects of anti-hypertensive drugs on esophageal body contraction

    Institute of Scientific and Technical Information of China (English)

    Koichi; Yoshida; Kenji; Furuta; Kyoichi; Adachi; Shunji; Ohara; Terumi; Morita; Takashi; Tanimura; Shuji; Nakata; Masaharu; Miki; Kenji; Koshino; Yoshikazu; Kinoshita

    2010-01-01

    AIM:To clarify the effects of anti-hypertensive drugs on esophageal contraction and determine their possi-ble relationship with gastro-esophageal reflux disease.METHODS:Thirteen healthy male volunteers were enrolled. Esophageal body peristaltic contractions and lower esophageal sphincter (LES) pressure were measured using high resolution manometry. All subjects were randomly examined on four separate occasions following administrations of nifedipine,losartan,and atenolol,as well as without any drug administ...

  6. On the Feasibility of Steering Swallowable Microsystem Capsules Using Computer-Aided Magnetic Levitation

    OpenAIRE

    Wu, Billy; Mintchev, Martin

    2008-01-01

    Swallowable capsule endoscopy is used for non-invasive diagnosis of some gastrointestinal (GI) organs. However, control over the position of the capsule is a major unresolved issue. This study presents a design for steering the capsule based on magnetic levitation. The levitation is stabilized with the aid of a computer-aided feedback control system and diamagnetism. Peristaltic and gravitational forces to be overcome were calculated. A levitation setup was built to analyze the fe...

  7. Convective Heat Transfer Analysis on Prandtl Fluid Model with Peristalsis

    Directory of Open Access Journals (Sweden)

    A. Alsaedi

    2013-01-01

    Full Text Available The effects of magnetohydrodynamic (MHD on peristaltic transport of Prandtl fluid in a symmetric channel have been studied under the assumptions of long wave length and low-Reynolds number. Channel walls are considered compliant in nature. Series solutions of axial velocity, stream function and temperature are given by using regular perturbation technique for small values of Prandtl fluid parameter. The effects of physical parameters on the velocity, streamlines and temperature are examined by plotting graphs.

  8. Flexible gastrointestinal motility pressure sensors based on aluminum thin-film strain-gauge arrays

    OpenAIRE

    Silva, Luís Rebelo; Sousa, Paulo J.; L.M. Gonçalves; Minas, Graça

    2015-01-01

    This paper reports on an innovative approach to measuring intraluminal pressure in the upper gastrointestinal (GI) tract, especially monitoring GI motility and peristaltic movements. The proposed approach relies on thin-film aluminum strain gauges deposited on top of a Kapton membrane, which in turn lies on top of an SU-8 diaphragm-like structure. This structure enables the Kapton membrane to bend when pressure is applied, thereby affecting the strain gauges and effectively cha...

  9. Interstitial cells of Cajal, the Maestro in health and disease

    Institute of Scientific and Technical Information of China (English)

    Randa; M; Mostafa; Yasser; M; Moustafa; Hosam; Hamdy

    2010-01-01

    Interstitial cells of Cajal (ICC) are important players in the symphony of gut motility. They have a very signif icant physiological role orchestrating the normal peristaltic activity of the digestive system. They are the pacemaker cells in gastrointestinal (GI) muscles. Absence, reduction in number or altered integrity of the ICC network may have a dramatic effect on GI system motility. More understanding of ICC physiology will foster advances in physiology of gut motility which will help in a future break...

  10. A New Concept of a Drug Delivery System with Improved Precision and Patient Safety Features

    OpenAIRE

    Florian Thoma; Frank Goldschmidtböing; Peter Woias

    2014-01-01

    This paper presents a novel dosing concept for drug delivery based on a peristaltic piezo-electrically actuated micro membrane pump. The design of the silicon micropump itself is straight-forward, using two piezoelectrically actuated membrane valves as inlet and outlet, and a pump chamber with a piezoelectrically actuated pump membrane in-between. To achieve a precise dosing, this micropump is used to fill a metering unit placed at its outlet. In the final design this metering unit will be ma...

  11. New deep glass etching technology

    OpenAIRE

    Bu, M.; Melvin, T; Ensell, G; J. S. Wilkinson; Evans, A.G.R.

    2003-01-01

    A new masking technology useful for wet etching of glass, to a depth of more than 300 ?m, is reported; multilayers of metal in combination with thick SPRT220 photoresist, are used. This new method was successfully developed for fabricating a 200 ?m thick diaphragm for a micro peristaltic pump. Various mask materials, which can be patterned by standard photolithography and metal etching processes, were investigated. The main advantage of this newly developed method was the application of hydro...

  12. Collection of islets of Langerhans using an equilibrium method

    OpenAIRE

    Koh, Duk-Su; Moody, Mark; Jo, Junghyo

    2013-01-01

    Here we present a convenient method for easy hand-selection of enzymatically isolated small tissues such as islets. This method using a micropipette tip connected to a peristaltic pump collects islets in the tip continuously. After entering a conical micropipette tip, islets are quickly dragged up by solution flow, and this movement subsequently decreases as the flow rate decreases. The islets are trapped at a specific height when downward gravitation balances upward buoyancy and drag provide...

  13. Evaluation of blood compatibility of plasma deposited heparin-like films and SF6 plasma treated surfaces

    OpenAIRE

    Ivanira Antunes Perrenoud; Elidiane Cipriano Rangel; Rogério Pinto Mota; Steven Frederick Durrant; Nilson Cristino da Cruz

    2010-01-01

    In devices used in open-heart surgery and dialysis, blood must be continuously processed using extracorporeal circuits composed of peristaltic pumps and active components such as specific filters and oxygenators. Several procedures have been employed to avoid blood coagulation induced by contact with the artificial surfaces of such devices. Often heparin, a bioactive protein able to prevent clot formation, is employed. In this work, we have used heparin-containing gas plasmas to evaluate the ...

  14. Flow of MHD Carreau Fluid in a Curved Channel

    Directory of Open Access Journals (Sweden)

    Saima Noreen

    2013-01-01

    Full Text Available Analysis has been made for the curvature effects on the MHD peristaltic flow of an incompressible Carreau fluid in a channel. The flow problem is first reduced in the wave frame of reference and then solved after employing the long wavelength and low Reynolds number approximations. Expressions of stream function, pressure gradient, magnetic force function, induced magnetic field and current density are derived and then examined for various parameters of interest.

  15. Magnetohydrodynamic flow of a Carreau fluid in an channel with different wave forms

    Energy Technology Data Exchange (ETDEWEB)

    Hayat, Tasawar [Quaid-i-Azam Univ., Islamabad (Pakistan). Dept. of Mathematics; King Saud Univ., Riyadh (Saudi Arabia). Dept. of Mathematics; Saleem, Najma [Quaid-i-Azam Univ., Islamabad (Pakistan). Dept. of Mathematics; Mesloub, Said [King Saud Univ., Riyadh (Saudi Arabia). Dept. of Mathematics; Ali, Nasir [International Islamic Univ., Islamabad (Pakistan). Faculty of Basic and Applied Sciences

    2011-03-15

    In this investigation, we discuss the peristaltic motion based on the constitutive equations of a Carreau fluid in a channel. The fluid is electrically conducting in the presence of a uniform applied magnetic field. Four different wave forms are chosen. The fluid behaviour is studied using long wavelength approximation. Detailed analysis is performed for various emerging parameters on pumping and trapping phenomena. The present results reduce favourably with the currently available results of hydrodynamic case when the Hartman number is chosen zero. (orig.)

  16. Single column sequential extraction of Ra, Nd, Th, Pa and U from a natural sample

    OpenAIRE

    Jeandel, C.; Venchiarutti, C.; Bourquin, M.; Pradoux, C; Lacan, F.; P. van Beek; Riotte, Jean

    2011-01-01

    A new procedure allowing the sequential extraction of Ra, Nd, Th, Pa and U from the same initial natural sample (sea or river waters, particles, sediments, rocks) is proposed. Extraction recoveries were better than 90%. Procedural blanks ranged from 80 pg (for Nd) to below 1 fg, the detection limit of the MC-ICP-MS used (for Pa); all were negligible compared with the amounts of elements currently determined. Based on classical anionic resins attached to a peristaltic pump allowing precise flo...

  17. Organ culture of fetal rat small intestine for testing gluten toxicity: a reappraisal.

    OpenAIRE

    Wood, G. M.; Howdle, P. D.; Losowsky, M. S.

    1987-01-01

    Jejunal segments from fetal rats of 18 days gestation were maintained in an organ culture system for up to 72 h. During this period, villi developed within the intestinal lumen and the epithelium changed from stratified to simple columnar. Peristaltic activity was observed during in-vitro culture. Alkaline phosphatase specific activity of the bowel segments fell after 48 hours culture, compared with pre-culture values (P less than 0.05), but that of alpha-glucosidase increased. The addition o...

  18. LabVIEW-based sequential-injection analysis system for the determination of trace metals by square-wave anodic and adsorptive stripping voltammetry on mercury-film electrodes

    OpenAIRE

    Anastasios Economou; Anastasios Voulgaropoulos

    2003-01-01

    The development of a dedicated automated sequential-injection analysis apparatus for anodic stripping voltammetry (ASV) and adsorptive stripping voltammetry (AdSV) is reported. The instrument comprised a peristaltic pump, a multiposition selector valve and a home-made potentiostat and used a mercury-film electrode as the working electrodes in a thin-layer electrochemical detector. Programming of the experimental sequence was performed in LabVIEW 5.1. The sequence of operations included format...

  19. Sensitive and Real-Time Method for Evaluating Corneal Barrier Considering Tear Flow

    OpenAIRE

    Nakamura, Tadahiro; Teshima, Mugen; Kitahara, Takashi; Sasaki, Hitoshi; Uematsu, Masafumi; Kitaoka, Takashi; Nakashima, Mikiro; Nishida, Koyo; Nakamura, Junzo; Higuchi, Shun

    2010-01-01

    We developed a new electrophysiological method mimicking tear flow to evaluate the epithelial tight junction of rabbit cornea quantitatively. We investigated the effect of tear flow on the corneal damage induced by ophthalmic preservatives using this method. An Ussing chamber system with Ag/AgCl electrodes was used in the electrophysiological experiment. The excised rabbit cornea was mounted in the Ussing chamber and the precorneal solution in the chamber was perfused with a peristaltic pump ...

  20. Deformation Analysis of a Pneumatically-Activated Polydimethylsiloxane (PDMS) Membrane and Potential Micro-Pump Applications

    OpenAIRE

    Chi-Han Chiou; Tai-Yen Yeh; Jr-Lung Lin

    2015-01-01

    This study presents a double-side diaphragm peristaltic pump for efficient medium transport without the unwanted backflow and the lagging effect of a diaphragm. A theoretical model was derived to predict the important parameter of the micropump, i.e., the motion of the valves at large deformations, for a variety of air pressures. Accordingly, we proposed an easy and robust design to fabricate a Polydimethylsiloxane (PDMS)-based micropump. The theoretical model agrees with a numerical model an...

  1. A Continuous Flow System for the Measurement of Ambient Nitrogen Oxides [NO + NO2] Using Rhodamine B Hydrazide as a Chemosensor

    OpenAIRE

    Pandurangappa Malingappa; Venkataramanappa Yarradoddappa

    2014-01-01

    A new chemosensor has been used to monitor atmospheric nitrogen oxides [NO + NO2] at parts per billion (ppb) level. It is based on the catalytic reaction of nitrogen oxides with rhodamine B hydrazide (RBH) to produce a colored compound through the hydrolysis of the amide bond of the molecule. A simple colorimeter has been used to monitor atmospheric nitrogen dioxide at ppb level. The air samples were purged through a sampling cuvette containing RBH solution using peristaltic pump. The propose...

  2. Multi-column step-gradient chromatography system for automated ion exchange separations

    International Nuclear Information System (INIS)

    A multi-column step-gradient chromatography system has been designed to perform automated sequential separations of radionuclides by ion exchange chromatography. The system consists of a digital programmer with automatic stream selection valve, two peristaltic pumps, ten columns, and a fraction collector. The automation allows complicated separations of radionuclides to be made with minimal analyst attention and allows for increased productivity and reduced cost of analyses. Results are reported for test separations on mixtures of radionuclides by the system

  3. Analysis and Implementation of Multiple Bionic Motion Patterns for Caterpillar Robot Driven by Sinusoidal Oscillator

    OpenAIRE

    Yanhe Zhu; Xiaolu Wang; Jizhuang Fan; Sajid Iqbal; Dongyang Bie; Jie Zhao

    2014-01-01

    Articulated caterpillar robot has various locomotion patterns—which make it adaptable to different tasks. Generally, the researchers have realized undulatory (transverse wave) and simple rolling locomotion. But many motion patterns are still unexplored. In this paper, peristaltic locomotion and various additional rolling patterns are achieved by employing sinusoidal oscillator with fixed phase difference as the joint controller. The usefulness of the proposed method is verified using simulati...

  4. In Vitro Testing of a Novel Blood Pump Designed for Temporary Extracorporeal Support

    OpenAIRE

    Spurlock, DJ; Ranney, DN; Fracz, E; Mazur,; Bartlett, RH; Haft, JW

    2012-01-01

    Extracorporeal blood pumps are used as temporary ventricular assist devices or for extracorporeal membrane oxygenation. The ideal pump would be intrinsically self-regulating, carry no risk of cavitation or excessive inlet suction, be afterload insensitive, and valveless thus reducing thrombogenicity. Currently used technology, including roller, centrifugal, and pneumatic pulsatile pumps, does not meet these requirements. We studied a non-occlusive peristaltic pump (M-Pump) in two mock circula...

  5. Successful in vitro expansion and Characterization of Human Enteric Neuronal cells- A step towards Cell based therapies for Hirschsprung’s disease

    OpenAIRE

    Balamurugan M.; Preethy SP; Tholcopiyan L; Thamaraikannan; Srinivasan V; Murugan P; Manjunath S; Srinivasan T; Krishnamohan J; Abraham S

    2010-01-01

    BACKGROUND: The Enteric Nervous system (ENS) is a part of the Peripheral nervous system (PNS) that controls the peristaltic activity of the gut wall which is essential for propulsion of food in the digestive tract. It is composed of a large number of neurons and glial cells, distributed throughout the length of the gut. These ganglion cells develop from the neural crest in the embryo. Failure of complete colonization of the gut by these enteric neural crest cells during early development of l...

  6. Development of blood extraction system designed by female mosquito's blood sampling mechanism for bio-MEMS

    Science.gov (United States)

    Tsuchiya, Kazuyoshi; Nakanishi, Naoyuki; Nakamachi, Eiji

    2005-02-01

    A compact and wearable wristwatch type Bio-MEMS such as a health monitoring system (HMS) to detect blood sugar level for diabetic patient, was newly developed. The HMS consists of (1) a indentation unit with a microneedle to generate the skin penetration force using a shape memory alloy(SMA) actuator, (2) a pumping unit using a bimorph PZT piezoelectric actuator to extract the blood and (3) a gold (Au) electrode as a biosensor immobilized GOx and attached to the gate electrode of MOSFET to detect the amount of Glucose in extracted blood. GOx was immobilized on a self assembled spacer combined with an Au electrode by the cross-link method using BSA as an additional bonding material. The device can extract blood in a few microliter through a painless microneedle with the negative pressure by deflection of the bimorph PZT piezoelectric actuator produced in the blood chamber, by the similar way the female mosquito extracts human blood with muscle motion to flex or relax. The performances of the liquid sampling ability of the pumping unit through a microneedle (3.8mm length, 100μm internal diameter) using the bimorph PZT piezoelectric microactuator were measured. The blood extraction micro device could extract human blood at the speed of 2μl/min, and it is enough volume to measure a glucose level, compared to the amount of commercial based glucose level monitor. The electrode embedded in the blood extraction device chamber could detect electrons generated by the hydrolysis of hydrogen peroxide produced by the reaction between GOx and glucose in a few microliter extracted blood, using the constant electric current measurement system of the MOSFET type hybrid biosensor. The output voltage for the glucose diluted in the chamber was increased lineally with increase of the glucose concentration.

  7. Function of longitudinal vs circular muscle fibers in esophageal peristalsis, deduced with mathematical modeling

    Institute of Scientific and Technical Information of China (English)

    James G Brasseur; Mark A Nicosia; Anupam Pal; Larr S Miller

    2007-01-01

    We summarize from previous works the functions of circular vs. longitudinal muscle in esophageal peristaltic bolus transport using a mix of experimental data, the conservation laws of mechanics and mathematical modeling. Whereas circular muscle tone generates radial closure pressure to create a local peristaltic closure wave, longitudinal muscle tone has two functions, one physiological with mechanical implications, and one purely mechanical. Each of these functions independently reduces the tension of individual circular muscle fibers to maintain closure as a consequence of shortening of longitudinal muscle locally coordinated with increasing circular muscle tone. The physiological function is deduced by combining basic laws of mechanics with concurrent measurements of intraluminal pressure from manometry, and changes in cross sectional muscle area from endoluminal ultrasound from which local longitudinal shortening (LLS) can be accurately obtained. The purely mechanical function of LLS was discovered from mathematical modeling of peristaltic esophageal transport with the axial wall motion generated by LLS. Physiologically, LLS concentrates circular muscle fibers where closure pressure is highest.However, the mechanical function of LLS is to reduce the level of pressure required to maintain closure. The combined physiological and mechanical consequences of LLS are to reduce circular muscle fiber tension and power by as much as 1/10 what would be required for peristalsis without the longitudinal muscle layer, a tremendous benefit that may explain the existence of longitudinal muscle fiber in the gut. We also review what is understood of the role of longitudinal muscle in esophageal emptying, reflux and pathology.

  8. Static shape control of a flat shell structure

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The eight-node and forty-DOF piezoelectric shell element were applied to shape control of a flat shell structure. By the direct and converse effects, a distributed piezoelectric sensor layer was used to monitor the shape deformation and a distributed actuator layer was used to suppresse the deflection. A finite element model was for static response of laminated shell with piezoelectric sensors/actuators was derived. The model was verified by calculating piezoelectric polymeric PVDF bimorph beam. The results are in good agreement with those obtained by theoretical analysis of Tzou[1] and Hwang[2]. A case study of the static shape control of a flat shell structure is presented.

  9. A magnetoelectric composite based signal generator

    Science.gov (United States)

    Fetisov, Y. K.; Serov, V. N.; Fetisov, L. Y.; Makovkin, S. A.; Viehland, D.; Srinivasan, G.

    2016-05-01

    Self-oscillations in an active loop consisting of a wide-band amplifier and a magnetoelectric composite in the feedback circuit have been observed. The composite with a ferroelectric lead zirconate titanate bimorph and ferromagnetic Metglas serves as a resonator that determines the frequency of oscillations and provides the feedback voltage. Under amplitude balance and phase matching conditions, the device generated signals at 2.3 kHz, at the bending resonance frequency of the composite. The oscillations were observed over a specific range of magnetic bias H. The shape of the signal generated is dependent on electrical circuit parameters and magnitude and orientation of H.

  10. Mechano-optical wavelength tuning in a photonic crystal microcavity with sub-1 V drive voltage.

    Science.gov (United States)

    Abdulla, Shahina M C; Kauppinen, Lasse J; Krijnen, Gijs J M; de Ridder, René M

    2012-06-01

    A micro-bimorph cantilever with self-aligned nanotips is monolithically integrated with a photonic crystal based device using optical and deep UV lithography techniques. Upon electrostatic actuation, the dielectric nanotips perturb the optical field, providing electromechano-optical modulation of light. Static tuning of the optical transmission spectra by more than 600 pm is measured with a sub-1 V drive voltage, resulting in a modulation as high as 21 dB. The observed strong electromechano-optical effect may find application in power efficient devices for optical communication networks, such as wavelength routing elements.

  11. Tunable optical lens array using viscoelastic material and acoustic radiation force

    Energy Technology Data Exchange (ETDEWEB)

    Koyama, Daisuke, E-mail: dkoyama@mail.doshisha.ac.jp; Kashihara, Yuta; Matsukawa, Mami [Faculty of Science and Engineering, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe 610-0321 (Japan); Wave Electronics Research Center, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe 610-0321 (Japan); Hatanaka, Megumi [Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe 610-0321 (Japan); Wave Electronics Research Center, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe 610-0321 (Japan); Nakamura, Kentaro [Precision and Intelligence Laboratory, Tokyo Institute of Technology, 4259-R2-26, Nagatsutacho, Midoriku, Yokohama 226-8503 (Japan)

    2015-10-28

    A movable optical lens array that uses acoustic radiation force was investigated. The lens array consists of a glass plate, two piezoelectric bimorph transducers, and a transparent viscoelastic gel film. A cylindrical lens array with a lens pitch of 4.6 mm was fabricated using the acoustic radiation force generated by the flexural vibration of the glass plate. The focal point and the positioning of the lenses can be changed using the input voltage and the driving phase difference between the two transducers, respectively.

  12. 惯性冲击驱动管内移动机器人设计%A piezoelectric in-pipe micro robot actuated by impact drive mechanism

    Institute of Scientific and Technical Information of China (English)

    刘品宽; 温志杰; 李锦

    2008-01-01

    A piezoelectric in-pipe micro robot with bimorph structure and actuated by the Impact Drive Mechanism(IDM)theory is presented in this paper.The basic structure of this actuator is composed of two piezoelectric bimorph sheets and an inertia mass connected in series.While operating,the deflection of the two piezoelectric bimorph sheets is translated into linear movement by the IDM to complete the system actuation.AS the essence of the IDM theory,the relationship between the inertia impact force generated by the deflection of the bimorph sheets and the friction between moving body and pipe inwall is analyzed theoretically.Then,the dynamic performance of the system is simulated both by MATLAB and by ANSYS.The results show that the step displacement could be minified to 0.15μm,and the proposed actuator is higher accurate and higher efficient for medical and industrial applications.%设计了一种以压电双层膜为基本结构,通过惯性冲击原理达到运动驱动目的的管内移动机器人.该机器人主要由一个典型的压电双层膜结构和惯性质量串联构成.工作时,压电双层膜的变形由惯性冲击转化为整体结构的直线位移.从理论上分析了惯性冲击原理的核心问题:惯性冲击力与管壁和机器人之间摩擦力的关系,并通过MATLAB和AN-SYS等软件对整个系统的动态响应做了仿真.相关的验证表明,所设计的管内移动机器人运动步长可以达到0.15μm,具有精密运动和高效率的优点,可以在工业中广泛应用.

  13. A versatile multi-user polyimide surface micromachinning process for MEMS applications

    KAUST Repository

    Carreno, Armando Arpys Arevalo

    2015-04-01

    This paper reports a versatile multi-user micro-fabrication process for MEMS devices, the \\'Polyimide MEMS Multi-User Process\\' (PiMMPs). The reported process uses polyimide as the structural material and three separate metallization layers that can be interconnected depending on the desired application. This process enables for the first time the development of out-of-plane compliant mechanisms that can be designed using six different physical principles for actuation and sensing on a wafer from a single fabrication run. These principles are electrostatic motion, thermal bimorph actuation, capacitive sensing, magnetic sensing, thermocouple-based sensing and radio frequency transmission and reception. © 2015 IEEE.

  14. Development of adjustable grazing incidence optics for Generation-X

    Science.gov (United States)

    Reid, Paul B.; Murray, Stephen S.; Trolier-McKinstry, Susan; Freeman, Mark; Juda, Michael; Podgorski, William; Ramsey, Brian; Schwartz, Daniel

    2008-07-01

    For X-ray astronomy, 0.1 arc-second imaging resolution will result in a significant advance in our understanding of the Universe. Similarly, the advent of low cost high performance X-ray mirrors will also increase the likelihood of more X-ray telescopes being funded and built. We discuss the development plans of two different types of adjustable grazing incidence optics: one being a tenth arc-second resolution bimorph mirror approach also suitable for extremely large collecting areas, and the second being a few arc-second radially adjustable mirror approach more suitable for modest sized telescopes. Bimorph mirrors will be developed using thin (0.1 - 0.4 mm) thermally formed glass or electroplated metal mirror segments with thin film piezo-electric actuators deposited directly on the mirror back surface. Mirror figure will be adjusted on-orbit. Radially adjustable mirrors will employ discreet radially electrostrictive actuators for mirror alignment and low spatial error frequency figure correction during assembly and alignment. In this paper we report on. In this paper we describe mirror design and our development plans for both mirror concepts.

  15. Piezoelectric Energy Harvesting in Internal Fluid Flow

    Directory of Open Access Journals (Sweden)

    Hyeong Jae Lee

    2015-10-01

    Full Text Available We consider piezoelectric flow energy harvesting in an internal flow environment with the ultimate goal powering systems such as sensors in deep oil well applications. Fluid motion is coupled to structural vibration via a cantilever beam placed in a converging-diverging flow channel. Two designs were considered for the electromechanical coupling: first; the cantilever itself is a piezoelectric bimorph; second; the cantilever is mounted on a pair of flextensional actuators. We experimentally investigated varying the geometry of the flow passage and the flow rate. Experimental results revealed that the power generated from both designs was similar; producing as much as 20 mW at a flow rate of 20 L/min. The bimorph designs were prone to failure at the extremes of flow rates tested. Finite element analysis (FEA showed fatigue failure was imminent due to stress concentrations near the bimorph’s clamped region; and that robustness could be improved with a stepped-joint mounting design. A similar FEA model showed the flextensional-based harvester had a resonant frequency of around 375 Hz and an electromechanical coupling of 0.23 between the cantilever and flextensional actuators in a vacuum. These values; along with the power levels demonstrated; are significant steps toward building a system design that can eventually deliver power in the Watts range to devices down within a well.

  16. Structure–performance relationships for cantilever-type piezoelectric energy harvesters

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Kyung-Hoon, E-mail: kh97.cho@samsung.com, E-mail: spriya@vt.edu; Park, Hwi-Yeol; Heo, Jin S. [Samsung Advanced Institute of Technology, Samsung Electronics, Yongin 446-712 (Korea, Republic of); Priya, Shashank, E-mail: kh97.cho@samsung.com, E-mail: spriya@vt.edu [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Virginia 24061 (United States)

    2014-05-28

    This study provides comprehensive analysis of the structure–performance relationships in cantilever-type piezoelectric energy harvesters. It provides full understanding of the effect of all the practical global control variables on the harvester performance. The control variables considered for the analysis were material parameters, areal and volumetric dimensions, and configuration of the inactive and active layers. Experimentally, the output power density of the harvester was maximum when the shape of the beam was close to a square for a constant bending stiffness and a fixed beam area. Through analytical modeling of the effective stiffness for the piezoelectric bimorph, the conditions for enhancing the bending stiffness within the same beam volume as that of a conventional bimorph were identified. The harvester configuration with beam aspect ratio of 0.86 utilizing distributed inactive layers exhibited an giant output power of 52.5 mW and power density of 28.5 mW cm{sup −3} at 30 Hz under 6.9 m s{sup −2} excitation. The analysis further indicates that the trend in the output power with varying damping ratio is dissimilar to that of the efficiency. In order to realize best performance, the harvester should be designed with respect to maximizing the magnitude of output power.

  17. Characteristic of TiNi(Cu) shape memory thin film based on micropump

    Science.gov (United States)

    Zhang, Huijun; Qiu, Chengjun

    2009-07-01

    Shape memory thin films offer a unique combination of novel properties and have the potential to become a primary actuating mechanism for micropumps. In this study, a micropump driven by TiNiCu shape memory thin film is designed and fabricated. The micropump is composed of a TiNiCu/Si bimorph driving membrane, a pump chamber and two inlet and outlet check valves. The property of TiNiCu films and driving capacity of TiNiCu/Si bimorph driving membrane are investigated. By using the recoverable force of TiNiCu thin film and biasing force of silicon membrane, the actuation diaphragm realizes reciprocating motion effectively. Experimental results show that the film surface appears a smooth and featureless morphology without any cracks, and the hysteresis width ΔT of TiNiCu film is about 2-3°C, the micropump driving by TiNiCu film has good performance, such as high pumping yield, high working frequency, stable driving capacity, and long fatigue life time.

  18. Research on an inertial piezoelectric actuator for a micro in-pipe robot

    Institute of Scientific and Technical Information of China (English)

    YANG Zhi-xin; SUN Bao-yuan

    2006-01-01

    A new kind of inertial piezoelectric actuator for a micro in-pipe robot is proposed and studied. The actuator is composed of a body, corresponding to a mass rod, and four elastic legs. Each leg is a composite piezoelectric bimorph beam, made up of a middle metal element, an upper and lower piezoelectric elements. The mechanism is driven by an asymmetric waveform voltage, such as saw-toothed waveform, and utilizes the dynamic relationship between the maximum static friction force and the inertial force. To study the actuator, firstly, the constituent equation of a composite piezoelectric bimorph under both applied voltage and external force was inferred by thermodynamics. Secondly, the dynamic model of the actuator was established analyzing the relationship between the locomotive states, viz. displacement and velocity, and design parameters, such as piezoelectric strain constant, elastic modulus, length, width and thickness of the piezoelectric element, actuator mass, and driving voltage. At last, the dynamic equation was solved and the theoretical calculation of the inherent frequency was more consistent with the experimental data, which proved the rationality of the model. All these lay a theoretical foundation of the micro actuator parameter optimization and more research on a micro robot.

  19. Adaptive optics ophthalmologic systems using dual deformable mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Jones, S; Olivier, S; Chen, D; Sadda, S; Joeres, S; Zawadzki, R; Werner, J S; Miller, D

    2007-02-01

    Adaptive Optics (AO) have been increasingly combined with a variety of ophthalmic instruments over the last decade to provide cellular-level, in-vivo images of the eye. The use of MEMS deformable mirrors in these instruments has recently been demonstrated to reduce system size and cost while improving performance. However, currently available MEMS mirrors lack the required range of motion for correcting large ocular aberrations, such as defocus and astigmatism. In order to address this problem, we have developed an AO system architecture that uses two deformable mirrors, in a woofer/tweeter arrangement, with a bimorph mirror as the woofer and a MEMS mirror as the tweeter. This setup provides several advantages, including extended aberration correction range, due to the large stroke of the bimorph mirror, high order aberration correction using the MEMS mirror, and additionally, the ability to ''focus'' through the retina. This AO system architecture is currently being used in four instruments, including an Optical Coherence Tomography (OCT) system and a retinal flood-illuminated imaging system at the UC Davis Medical Center, a Scanning Laser Ophthalmoscope (SLO) at the Doheny Eye Institute, and an OCT system at Indiana University. The design, operation and evaluation of this type of AO system architecture will be presented.

  20. Speckle-based at-wavelength metrology of X-ray mirrors with super accuracy.

    Science.gov (United States)

    Kashyap, Yogesh; Wang, Hongchang; Sawhney, Kawal

    2016-05-01

    X-ray active mirrors, such as bimorph and mechanically bendable mirrors, are increasingly being used on beamlines at modern synchrotron source facilities to generate either focused or "tophat" beams. As well as optical tests in the metrology lab, it is becoming increasingly important to optimise and characterise active optics under actual beamline operating conditions. Recently developed X-ray speckle-based at-wavelength metrology technique has shown great potential. The technique has been established and further developed at the Diamond Light Source and is increasingly being used to optimise active mirrors. Details of the X-ray speckle-based at-wavelength metrology technique and an example of its applicability in characterising and optimising a micro-focusing bimorph X-ray mirror are presented. Importantly, an unprecedented angular sensitivity in the range of two nanoradians for measuring the slope error of an optical surface has been demonstrated. Such a super precision metrology technique will be beneficial to the manufacturers of polished mirrors and also in optimization of beam shaping during experiments.

  1. Application of EAP materials toward a refreshable Braille display

    Science.gov (United States)

    Di Spigna, N.; Chakraborti, P.; Yang, P.; Ghosh, T.; Franzon, P.

    2009-03-01

    The development of a multiline, refreshable Braille display will assist with the full inclusion and integration of blind people into society. The use of both polyvinylidene fluoride (PVDF) film planar bending mode actuators and silicone dielectric elastomer cylindrical tube actuators have been investigated for their potential use in a Braille cell. A liftoff process that allows for aggressive scaling of miniature bimorph actuators has been developed using standard semiconductor lithography techniques. The PVDF bimorphs have been demonstrated to provide enough displacement to raise a Braille dot using biases less than 1000V and operating at 10Hz. In addition, silicone tube actuators have also been demonstrated to achieve the necessary displacement, though requiring higher voltages. The choice of electrodes and prestrain conditions aimed at maximizing axial strain in tube actuators are discussed. Characterization techniques measuring actuation displacement and blocking forces appropriate for standard Braille cell specifications are presented. Finally, the integration of these materials into novel cell designs and the fabrication of a prototype Braille cell are discussed.

  2. Fabrication of functionally graded PZT/Pt piezoelectric actuators; PZT/Pt den'atsu actuator no keisha kinoka

    Energy Technology Data Exchange (ETDEWEB)

    Terakubo, N.; Li, J.F.; Ono, M.; Watanabe, R. [Tohoku University, Sendai (Japan)

    2000-11-15

    Piezoelectric materials have received increasing attention in the field of electromechanical system because they can readily transfer an electrical signal to a mechanical movement. Unimorph and bimorph actuators that contain a piezoelectric plate and a metal plate are widely used to generate a larger bending displacement than an extensional-mode transducer. However, degradation may occur at the organic bonding interfaces after long time service. In this work, to develop a functionally graded PZT/Pt piezoelectric actuator, PZT/Pt composites with various composition ratios were prepared and characterized. (1) Dense PZT/Pt composite samples without any chemical reaction between the PZT and Pt phases were obtained by sintering in air at 1,200 degree C for 1 h. (2) The PZT/Pt composites that contained 20vol% Pt or less exhibited dielectric and piezoelectric properties, with piezoelectric constant decreasing with increasing Pt content. (3) FGM PZT/Pt bimorph actuators were designed using Taya's model and successfully fabricated via powder metallurgical routes. (author)

  3. Nonlinear numerical modelling and experimental validation of multilayer piezoelectric vibration energy scavengers

    Science.gov (United States)

    Blažević, D.; Zelenika, S.

    2015-05-01

    Scavenging of low-level ambient vibrations i.e. the conversion of kinetic into electric energy, is proven as effective means of powering low consumption electronic devices such as wireless sensor nodes. Cantilever based scavengers are characterised by several advantages and thus thoroughly investigated; analytical models based on a distributed parameter approach, Euler-Bernoulli beam theory and eigenvalue analysis have thus been developed and experimentally verified. Finite element models (FEM) have also been proposed employing different modelling approaches and commercial software packages with coupled analysis capabilities. An approach of using a FEM analysis of a piezoelectric cantilever bimorph under harmonic excitation is used in this work. Modal, harmonic and linear and nonlinear transient analyses are performed. Different complex dynamic effects are observed and compared to the results obtained by using a distributed parameter model. The influence of two types of finite elements and three mesh densities is also investigated. A complex bimorph cantilever, based on commercially available Midé Technology® Volture energy scavengers, is then considered. These scavengers are characterised by an intricate multilayer structure not investigated so far in literature. An experimental set-up is developed to evaluate the behaviour of the considered class of devices. The results of the modal and the harmonic FEM analyses of the behaviour of the multilayer scavengers are verified experimentally for three different tip masses and 12 different electrical load values. A satisfying agreement between numerical and experimental results is achieved.

  4. Hydrodynamic thrust generation and power consumption investigations for piezoelectric fins with different aspect ratios

    Science.gov (United States)

    Shahab, S.; Tan, D.; Erturk, A.

    2015-12-01

    Bio-inspired hydrodynamic thrust generation using piezoelectric transduction has recently been explored using Macro-Fiber Composite (MFC) actuators. The MFC technology strikes a balance between the actuation force and structural deformation levels for effective swimming performance, and additionally offers geometric scalability, silent operation, and ease of fabrication. Recently we have shown that mean thrust levels comparable to biological fish of similar size can be achieved using MFC fins. The present work investigates the effect of length-to-width (L/b) aspect ratio on the hydrodynamic thrust generation performance of MFC cantilever fins by accounting for the power consumption level. It is known that the hydrodynamic inertia and drag coefficients are controlled by the aspect ratio especially for L/b< 5. The three MFC bimorph fins explored in this work have the aspect ratios of 2.1, 3.9, and 5.4. A nonlinear electrohydroelastic model is employed to extract the inertia and drag coefficients from the vibration response to harmonic actuation for the first bending mode. Experiments are then conducted for various actuation voltage levels to quantify the mean thrust resultant and power consumption levels for different aspect ratios. Variation of the thrust coefficient of the MFC bimorph fins with changing aspect ratio is also semi-empirically modeled and presented.

  5. Energy harvesting from mastication forces via a smart tooth

    Science.gov (United States)

    Bani-Hani, Muath; Karami, M. Amin

    2016-04-01

    The batteries of the current pacing devices are relatively large and occupy over 60 percent of the size of pulse generators. Therefore, they cannot be placed in the subtle areas of human body. In this paper, the mastication force and the resulting tooth pressure are converted to electricity. The pressure energy can be converted to electricity by using the piezoelectric effect. The tooth crown is used as a power autonomous pulse generator. We refer to this envisioned pulse generator as the smart tooth. The smart tooth is in the form of a dental implant. A piezoelectric vibration energy harvester is designed and modeled for this purpose. The Piezoelectric based energy harvesters investigated and analyzed in this paper initially includes a single degree of freedom piezoelectric based stack energy harvester which utilizes a harvesting circuit employing the case of a purely resistive circuit. The next step is utilizing and investigating a bimorph piezoelectric beam which is integrated/embedded in the smart tooth implant. Mastication process causes the bimorph beam to buckle or return to unbuckled condition. The transitions results in vibration of the piezoelectric beam and thus generate energy. The power estimated by the two mechanisms is in the order of hundreds of microwatts. Both scenarios of the energy harvesters are analytically modeled. The exact analytical solution of the piezoelectric beam energy harvester with Euler-Bernoulli beam assumptions is presented. The electro-mechanical coupling and the geometric nonlinearities have been included in the model for the piezoelectric beam.

  6. Magnetoelastic beam with extended polymer for low frequency vibration energy harvesting

    Science.gov (United States)

    Ibrahim, Alwathiqbellah; Towfighian, Shahrzad; Younis, Mohammad; Su, Quang

    2016-04-01

    Ambient energy in the form of mechanical kinetic energy is mostly considered waste energy. The process of scavenging and storing such energy is known as energy harvesting. Energy harvesting from mechanical vibration is performed using resonant energy harvesters (EH) with two major goals: enhancing the power scavenged at low frequency sources of vibrations, and increasing the efficiency of scavenging energy by increasing the bandwidth near the resonant frequency. Toward such goals, we propose a piezoelectric EH of a composite cantilever beam with a tip magnet facing another magnet at a distance. The composite cantilever consists of a piezoelectric bimorph with an extended polymer material. With the effect of the nonlinearity of the magnetic force, higher amplitude can be achieved because of the generated bi-stability oscillations of the cantilever beam under harmonic excitation. The contribution of the this paper is to demonstrate lowering the achieved resonant frequency down to 17 Hz compared to 100 Hz for the piezoelectric bimorph beam without the extended polymer. Depending on the magnetic distance, the beam responses are divided to mono and bi-stable regions, for which we investigate static and dynamic behaviors. The dynamics of the system and the frequency and voltage responses of the beam are obtained using the shooting method.

  7. Uterine contractions evaluated on cine MR imaging in patients with uterine leiomyomas

    International Nuclear Information System (INIS)

    Purpose: Submucosal leiomyoma is one of the most recognized causes of infertility and habitual abortion. The purpose of this study is to evaluate uterine peristalsis, a cycle-related inherent contractility of uterus probably responsible for sperm transport and conservation of pregnancy, in patients with uterine leiomyomas using cine magnetic resonance (MR) imaging. Materials and methods: Study population consisted of 26 female patients (age range: 19-51 years, mean: 41 years), in which 16 patients had submucosal leiomyomas and 10 patients had intramural or subserosal leiomyomas. We prospectively performed MR imaging of the midsagittal plane of uterus using 1.5 T magnet (Symphony, Siemens Medical Systems) with a body array coil, and obtained 60 half-Fourier acquisition single shot turbo spin echo (HASTE) images (Echo time=80 ms, FOV=300 mm, slice thickness 5 mm, matrix 256x256) within 2 min, and displayed them on cine mode at 12x faster than real speed. Evaluated were peristaltic movements at the endometral-myometrial junction and focal myometrial movements, adjacent to leiomyomas, regarding presence, direction, frequency, and conduction. Results: The peristaltic movements were identified in 12/16 patients with submucosal lesions and 10/10 with other leiomyomas. The frequency and direction were cycle-related. Loss of peristalsis was noted adjacent to submucosal myomas in 4/12 patients, but was not in others. Focal myometrial movements were noted in 9/16 patients with submucosal myomas, but not in others. Conclusions: Uterine peristaltic movements were partly interrupted by submucosal leiomoymas, but not by myometrial or subserosal leiomyomas. Loss of peristalsis and focal myometrial movements was noted only adjacent to submucosal leiomyomas. These findings are considered to represent dysfunctional contractility, and may be related with pregnancy loss

  8. Nanofluid transport in a living soft microtube

    International Nuclear Information System (INIS)

    The mechanism of hydrodynamic transport of nanoparticles in living tissues by intrinsic lymphatic pumping remains one of the fundamental questions in the field of nanomedicine. However, despite its importance, direct visualization of the nanofluid transport mechanism has not been achieved. In this article, we report a novel in situ fluorescence bioimaging method for observing real-time microflow patterns of nanofluids confined in a contracting and expanding soft microtube. This method allows for physiological monitoring of spatiotemporally resolved microfluidic behaviour and channel undulation during the peristaltic transport of fluorescent nanoparticle suspensions by lymph vessels embedded in bulky tissues at the location of the hindlimb. The fluorescent nanofluid conferred a high optical contrast for the visualization of the lymphatic microtube, with which the concentration and viscosity of the nanofluid could be determined. The nanofluid and microtube mechanics of the hindlimb lymph vessels exhibited similar behaviours as the previously described base fluid flow of peristaltic mesenteric lymph vessels. Specifically, the microtube contraction and expansion induced increased forward flows, and a reverse flow developed at the maximum contraction, all of which corresponded to Poiseuille flow and implied that higher tube wall shear stress was related to increased axial flow velocity. On the other hand, our study identified a highly heterogeneous flow pattern that could appear during the microtube expansion phase, whose axial velocity profile remarkably deviated from the Hagen–Poiseuille equation. In addition, the peristaltic pumping power was estimated to be on the nanowatt order of magnitude. Finally, we discuss the possible applications of this nanofluidic model system in the context of nanobiotechnology. (paper)

  9. Interpreting manometric signals for propulsion in the gut

    Science.gov (United States)

    Sinnott, M. D.; Cleary, P. W.; Dinning, P. G.; Arkwright, J. W.; Costa, M.

    2015-09-01

    Propulsion of intestinal contents involves coordinated contractions and relaxations of the muscle controlled by polarised enteric neural reflex pathways. Due to the inaccessibility of the small and large bowel, obtaining detailed manometric measurements in the gut or visualizing the movement of digesta is difficult in vivo. Computational modelling that incorporates the complex interactions between gut content and wall contractility has the potential to explain the mechanisms behind propulsive motor patterns and aid the interpretation of manometric measurements. We present here a biomechanical computational model of coupled wall flexure and flow dynamics in a virtual segment of intestine. The model uses the smoothed particle hydrodynamics method which permits coupling of the fluid/solid motion and wall deformation in a natural way. Peristaltic waves of contraction and relaxation, similar to those observed in physiological experiments, were applied to the gut wall of the model. A catheter containing manometric sensors was also incorporated into the model to derive representative pressure readings. The sensitivity of the model to input parameters including wall stiffness, viscosity of content and degree of muscular contraction is also presented. The results show that there is a rapid rise in pressure of fluid content trapped between the catheter and the contracting wall. The peristaltic wave travels along the length of the virtual segment of intestine passing over each sensor. The bolus, formed by the peristaltic contraction, grows in size and longitudinal extent until the bolus size reaches steady state. The wall force and the peak fluid pressure both scale proportionally with the change in muscle length, indicating that manometric data provide a reliable means for measuring the strength of contractions. Changes in stiffness of the wall and viscosity of contents result in predictable changes in the parameters of peristalsis. The model can be thus applied to manometry

  10. Nanofluid transport in a living soft microtube

    Science.gov (United States)

    Sung, Baeckkyoung; Kim, Se Hoon; Lee, Sungwoo; Lim, Jaekwan; Lee, Jin-Kyu; Soh, Kwang-Sup

    2015-09-01

    The mechanism of hydrodynamic transport of nanoparticles in living tissues by intrinsic lymphatic pumping remains one of the fundamental questions in the field of nanomedicine. However, despite its importance, direct visualization of the nanofluid transport mechanism has not been achieved. In this article, we report a novel in situ fluorescence bioimaging method for observing real-time microflow patterns of nanofluids confined in a contracting and expanding soft microtube. This method allows for physiological monitoring of spatiotemporally resolved microfluidic behaviour and channel undulation during the peristaltic transport of fluorescent nanoparticle suspensions by lymph vessels embedded in bulky tissues at the location of the hindlimb. The fluorescent nanofluid conferred a high optical contrast for the visualization of the lymphatic microtube, with which the concentration and viscosity of the nanofluid could be determined. The nanofluid and microtube mechanics of the hindlimb lymph vessels exhibited similar behaviours as the previously described base fluid flow of peristaltic mesenteric lymph vessels. Specifically, the microtube contraction and expansion induced increased forward flows, and a reverse flow developed at the maximum contraction, all of which corresponded to Poiseuille flow and implied that higher tube wall shear stress was related to increased axial flow velocity. On the other hand, our study identified a highly heterogeneous flow pattern that could appear during the microtube expansion phase, whose axial velocity profile remarkably deviated from the Hagen-Poiseuille equation. In addition, the peristaltic pumping power was estimated to be on the nanowatt order of magnitude. Finally, we discuss the possible applications of this nanofluidic model system in the context of nanobiotechnology.

  11. Uterine contractions evaluated on cine MR imaging in patients with uterine leiomyomas

    Energy Technology Data Exchange (ETDEWEB)

    Nishino, Mizuki E-mail: mizuki@mbox.kyoto-inet.or.jpnishinomizuki@hotmail.com; Togashi, Kaori; Nakai, Asako; Hayakawa, Katsumi; Kanao, Shotarou; Iwasaku, Kazuhiro; Fujii, Shingo

    2005-01-01

    Purpose: Submucosal leiomyoma is one of the most recognized causes of infertility and habitual abortion. The purpose of this study is to evaluate uterine peristalsis, a cycle-related inherent contractility of uterus probably responsible for sperm transport and conservation of pregnancy, in patients with uterine leiomyomas using cine magnetic resonance (MR) imaging. Materials and methods: Study population consisted of 26 female patients (age range: 19-51 years, mean: 41 years), in which 16 patients had submucosal leiomyomas and 10 patients had intramural or subserosal leiomyomas. We prospectively performed MR imaging of the midsagittal plane of uterus using 1.5 T magnet (Symphony, Siemens Medical Systems) with a body array coil, and obtained 60 half-Fourier acquisition single shot turbo spin echo (HASTE) images (Echo time=80 ms, FOV=300 mm, slice thickness 5 mm, matrix 256x256) within 2 min, and displayed them on cine mode at 12x faster than real speed. Evaluated were peristaltic movements at the endometral-myometrial junction and focal myometrial movements, adjacent to leiomyomas, regarding presence, direction, frequency, and conduction. Results: The peristaltic movements were identified in 12/16 patients with submucosal lesions and 10/10 with other leiomyomas. The frequency and direction were cycle-related. Loss of peristalsis was noted adjacent to submucosal myomas in 4/12 patients, but was not in others. Focal myometrial movements were noted in 9/16 patients with submucosal myomas, but not in others. Conclusions: Uterine peristaltic movements were partly interrupted by submucosal leiomoymas, but not by myometrial or subserosal leiomyomas. Loss of peristalsis and focal myometrial movements was noted only adjacent to submucosal leiomyomas. These findings are considered to represent dysfunctional contractility, and may be related with pregnancy loss.

  12. A mathematical simulation of the ureter: effects of the model parameters on ureteral pressure/flow relations.

    Science.gov (United States)

    Vahidi, Bahman; Fatouraee, Nasser; Imanparast, Ali; Moghadam, Abbas Nasiraei

    2011-03-01

    Ureteral peristaltic mechanism facilitates urine transport from the kidney to the bladder. Numerical analysis of the peristaltic flow in the ureter aims to further our understanding of the reflux phenomenon and other ureteral abnormalities. Fluid-structure interaction (FSI) plays an important role in accuracy of this approach and the arbitrary Lagrangian-Eulerian (ALE) formulation is a strong method to analyze the coupled fluid-structure interaction between the compliant wall and the surrounding fluid. This formulation, however, was not used in previous studies of peristalsis in living organisms. In the present investigation, a numerical simulation is introduced and solved through ALE formulation to perform the ureteral flow and stress analysis. The incompressible Navier-Stokes equations are used as the governing equations for the fluid, and a linear elastic model is utilized for the compliant wall. The wall stimulation is modeled by nonlinear contact analysis using a rigid contact surface since an appropriate model for simulation of ureteral peristalsis needs to contain cell-to-cell wall stimulation. In contrast to previous studies, the wall displacements are not predetermined in the presented model of this finite-length compliant tube, neither the peristalsis needs to be periodic. Moreover, the temporal changes of ureteral wall intraluminal shear stress during peristalsis are included in our study. Iterative computing of two-way coupling is used to solve the governing equations. Two phases of nonperistaltic and peristaltic transport of urine in the ureter are discussed. Results are obtained following an analysis of the effects of the ureteral wall compliance, the pressure difference between the ureteral inlet and outlet, the maximum height of the contraction wave, the contraction wave velocity, and the number of contraction waves on the ureteral outlet flow. The results indicate that the proximal part of the ureter is prone to a higher shear stress during

  13. Modelling and simulation of diffusive processes methods and applications

    CERN Document Server

    Basu, SK

    2014-01-01

    This book addresses the key issues in the modeling and simulation of diffusive processes from a wide spectrum of different applications across a broad range of disciplines. Features: discusses diffusion and molecular transport in living cells and suspended sediment in open channels; examines the modeling of peristaltic transport of nanofluids, and isotachophoretic separation of ionic samples in microfluidics; reviews thermal characterization of non-homogeneous media and scale-dependent porous dispersion resulting from velocity fluctuations; describes the modeling of nitrogen fate and transport

  14. Bioengineering fluid mechanics

    CERN Document Server

    Hung, Tin-kan

    2013-01-01

    This book highlights the basic concepts and equations for bioengineering flow processes. Physical concepts and meanings are emphasized while rigorous derivations are simplified, making it easier for self learning on some biological and medical flow processes. The well known Bernoulli equation in hydraulics is extended for pulsating flows, peristaltic flows and cardiac pumping. The dimensional analysis, model law and dimensionless equations can be related to computational models and experimental observations. The velocity vector imaging stored in echocardiograms can be used to analyze the pumping characteristics of the ventricular contraction. New topics included oxygen transport in membrane oxygenator and micro mixing of blood flow in capillary channels.

  15. Homogeneous-heterogeneous reaction effects in peristalsis through curved geometry

    Science.gov (United States)

    Hayat, Tasawar; Tanveer, Anum; Alsaadi, Fuad; Alotaibi, Naif D.

    2015-06-01

    This paper looks at the influence of homogeneous-heterogeneous reactions on the peristaltic transport of non-Newtonian fluid in a curved channel with wall properties. Constitutive relations for thermodynamic third grade material are utilized in the problem development. An electrically conducting fluid in the presence of radial applied magnetic field is considered. The governing flow equations are developed in the presence of viscous heating. Mathematical computations are simplified employing long wavelength and low Reynolds number considerations. The solutions for velocity, temperature, concentration and heat transfer coefficient are obtained and examined. The features of sundry parameters are analyzed by plotting graphs.

  16. Homogeneous-heterogeneous reaction effects in peristalsis through curved geometry

    Directory of Open Access Journals (Sweden)

    Tasawar Hayat

    2015-06-01

    Full Text Available This paper looks at the influence of homogeneous-heterogeneous reactions on the peristaltic transport of non-Newtonian fluid in a curved channel with wall properties. Constitutive relations for thermodynamic third grade material are utilized in the problem development. An electrically conducting fluid in the presence of radial applied magnetic field is considered. The governing flow equations are developed in the presence of viscous heating. Mathematical computations are simplified employing long wavelength and low Reynolds number considerations. The solutions for velocity, temperature, concentration and heat transfer coefficient are obtained and examined. The features of sundry parameters are analyzed by plotting graphs.

  17. Homogeneous-heterogeneous reaction effects in peristalsis through curved geometry

    Energy Technology Data Exchange (ETDEWEB)

    Hayat, Tasawar [Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan); Department of Electrical and Computer Engineering, Faculty of Engineering, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Tanveer, Anum, E-mail: qau14@yahoo.com; Alsaadi, Fuad [Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan); Alotaibi, Naif D. [Department of Electrical and Computer Engineering, Faculty of Engineering, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

    2015-06-15

    This paper looks at the influence of homogeneous-heterogeneous reactions on the peristaltic transport of non-Newtonian fluid in a curved channel with wall properties. Constitutive relations for thermodynamic third grade material are utilized in the problem development. An electrically conducting fluid in the presence of radial applied magnetic field is considered. The governing flow equations are developed in the presence of viscous heating. Mathematical computations are simplified employing long wavelength and low Reynolds number considerations. The solutions for velocity, temperature, concentration and heat transfer coefficient are obtained and examined. The features of sundry parameters are analyzed by plotting graphs.

  18. Resonance Frequency of Optical Microbubble Resonators: Direct Measurements and Mitigation of Fluctuations

    Science.gov (United States)

    Cosci, Alessandro; Berneschi, Simone; Giannetti, Ambra; Farnesi, Daniele; Cosi, Franco; Baldini, Francesco; Nunzi Conti, Gualtiero; Soria, Silvia; Barucci, Andrea; Righini, Giancarlo; Pelli, Stefano

    2016-01-01

    This work shows the improvements in the sensing capabilities and precision of an Optical Microbubble Resonator due to the introduction of an encaging poly(methyl methacrylate) (PMMA) box. A frequency fluctuation parameter σ was defined as a score of resonance stability and was evaluated in the presence and absence of the encaging system and in the case of air- or water-filling of the cavity. Furthermore, the noise interference introduced by the peristaltic and the syringe pumping system was studied. The measurements showed a reduction of σ in the presence of the encaging PMMA box and when the syringe pump was used as flowing system. PMID:27589761

  19. The Application of Flow Injection Technology to Automating Cold Vapor Mercury Analyses in Aquatic Ecosystems

    Directory of Open Access Journals (Sweden)

    TEODOROF, L.

    2009-02-01

    Full Text Available Based on flow injection techniques, FIMS is fully automated, fast, and cost-effective. The FIMS uses a high-performance single-beam optical system with a low pressure mercury lamp and solar-blind detector for maximum performance. The FIMS-400 has two stepper motor-driven peristaltic pumps for greater flexibility when used with optional accessories. FIMS is fully controlled from a personal computer using WinLab32 for AA software, a true Microsoft Windows-based program with an unparalleled offering of standard features, including a full range of analytical checks and quality control functions.

  20. The MainSTREAM Component Platform: A Holistic Approach to Microfluidic System Design

    DEFF Research Database (Denmark)

    Sabourin, David; Skafte-Pedersen, Peder; Søe, Martin Jensen;

    2013-01-01

    A microfluidic component library for building systems driving parallel or serial microfluidic-based assays is presented. The components are a miniaturized eight-channel peristaltic pump, an eight-channel valve, sample-to-waste liquid management, and interconnections. The library of components...... of reaction chips; (2) highly parallel pumping and routing/valving capability; (3) methods to interface pumps and chip-to-liquid management systems; (4) means to construct a portable system; (5) reconfigurability/flexibility in system design; (6) means to interface to microscopes; and (7) compatibility...

  1. Computed tomography studies of human brain movements

    International Nuclear Information System (INIS)

    Rhythmic brain movements have been revealed by sets of sequential computed tomography scans of human brains (seen retrospectively to be normal). These scans have shown that both (unenhanced) brain parenchymal density and the shapes of the elements of the supratentorial ventricular/cisternal system are subject to wave motions having similar periods - ranging from 26 s through 56 s, 77-96 s, 109 s and 224 s to 224 X 2 s (or even longer), with good correlation between peak values. These motions, as well as phase variations between the waves, suggest a peristaltic movement of cerebrospinal fluid through the ventricular/cisternal system with progressive axial damping

  2. Slow rhythmic ventricular oscillations and parenchymal density variations shown by sequential CT scanning

    International Nuclear Information System (INIS)

    Rhythmic brain movements have been revealed by sets of sequential computerised tomography scans of human brains (seen retrospectively to be normal). These scans have shown that both (unenhanced) brain parenchymal density and the shapes of the elements of the supratentorial ventricular/cisternal system are subject to wave motions having similar periods-ranging from 26 s through 56 s, 77-96 s, 109 s, and 224 s to 224 x 2 s (or even longer), with good correlation between peak values. These motions, as well as phase variations between the waves suggest a peristaltic movement of CSF through the ventricular/cisternal system with progressive axial damping

  3. Polychlorinated biphenyls (PCB) analysis report for solid sample from 219S tank 101

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, L.A.

    1998-02-04

    One waste sample that was obtained with solids from tank 101 of 219S via a peristaltic pump equipped with a stainless steel tube and Norprene tubing (Phthalate free) was obtained in a glass jar with teflon lid was analyzed (with duplicate, matrix spike, and matrix spike duplicate) for PCBs as Aroclor mixtures by the Inorganic/Organic Chemistry Group. A soxhlet extraction procedure was used for extraction of the Aroclors from the sample. Analysis was performed using dual column confirmation gas chromatography/electron capture detection (GC/ECD). Results are presented.

  4. Mixed convection flow of nanofluid in presence of an inclined magnetic field.

    Directory of Open Access Journals (Sweden)

    Saima Noreen

    Full Text Available This research is concerned with the mixed convection peristaltic flow of nanofluid in an inclined asymmetric channel. The fluid is conducting in the presence of inclined magnetic field. The governing equations are modelled. Mathematical formulation is completed through long wavelength and low Reynolds number approach. Numerical solution to the nonlinear analysis is made by shooting technique. Attention is mainly focused to the effects of Brownian motion and thermophoretic diffusion of nanoparticle. Results for velocity, temperature, concentration, pumping and trapping are obtained and analyzed in detail.

  5. Polychlorinated biphenyls (PCB) analysis report for solid sample from 219S tank 101

    International Nuclear Information System (INIS)

    One waste sample that was obtained with solids from tank 101 of 219S via a peristaltic pump equipped with a stainless steel tube and Norprene tubing (Phthalate free) was obtained in a glass jar with teflon lid was analyzed (with duplicate, matrix spike, and matrix spike duplicate) for PCBs as Aroclor mixtures by the Inorganic/Organic Chemistry Group. A soxhlet extraction procedure was used for extraction of the Aroclors from the sample. Analysis was performed using dual column confirmation gas chromatography/electron capture detection (GC/ECD). Results are presented

  6. Backflushing Filters for Field Processing of Water Samples Prior to Trace-Element Analyses

    Science.gov (United States)

    Kennedy, V.C.; Jenne, E.A.; Burchard, J.M.

    1976-01-01

    A portable unit is described for filtering water samples at field sites in such a manner that the filtrate is suitable for analysis not only of major constituents but also of trace elments at the mocrogram-per-liter level. A battery-operated peristaltic pump forces the water sample through medical-grade silicone tubing into and through an all-plastic in-line filter which can be backflushed when sediment clogs the filter membrane. Initial filtration rate exceeds 500 milliliter/minute and, because of the backflushing feature, a total time for filtering high-sediment-bearing waster samples is greatly reduced. (Woodard-USGS)

  7. Piezoelectric energy harvester having planform-tapered interdigitated beams

    Science.gov (United States)

    Kellogg, Rick A.; Sumali, Hartono

    2011-05-24

    Embodiments of energy harvesters have a plurality of piezoelectric planform-tapered, interdigitated cantilevered beams anchored to a common frame. The plurality of beams can be arranged as two or more sets of beams with each set sharing a common sense mass affixed to their free ends. Each set thus defined being capable of motion independent of any other set of beams. Each beam can comprise a unimorph or bimorph piezoelectric configuration bonded to a conductive or non-conductive supporting layer and provided with electrical contacts to the active piezoelectric elements for collecting strain induced charge (i.e. energy). The beams are planform tapered along the entirety or a portion of their length thereby increasing the effective stress level and power output of each piezoelectric element, and are interdigitated by sets to increase the power output per unit volume of a harvester thus produced.

  8. Vibration energy harvester with sustainable power based on a single-crystal piezoelectric cantilever array.

    Science.gov (United States)

    Kim, Moonkeun; Lee, Sang-Kyun; Ham, Yong-Hyun; Yang, Yil Suk; Kwon, Jong-Kee; Kwon, Kwang-Ho

    2012-08-01

    We designed and fabricated a bimorph cantilever array for sustainable power with an integrated Cu proof mass to obtain additional power and current. We fabricated a cantilever system using single-crystal piezoelectric material and compared the calculations for single and arrayed cantilevers to those obtained experimentally. The vibration energy harvester had resonant frequencies of 60.4 and 63.2 Hz for short and open circuits, respectively. The damping ratio and quality factor of the cantilever device were 0.012 and 41.66, respectively. The resonant frequency at maximum average power was 60.8 Hz. The current and highest average power of the harvester array were found to be 0.728 mA and 1.61 mW, respectively. The sustainable maximum power was obtained after slightly shifting the short-circuit frequency. In order to improve the current and power using an array of cantilevers, we also performed energy conversion experiments.

  9. Gliosarcoma: A rare variant of glioblastoma multiforme in paediatric patient: Case report and review of literature.

    Science.gov (United States)

    Meena, Ugan Singh; Sharma, Sumit; Chopra, Sanjeev; Jain, Shashi Kant

    2016-09-16

    Gliosarcoma is rare central nervous system tumour and a variant of glioblastoma multiforme with bimorphic histological pattern of glial and sarcomatous differentiation. It occurs in elderly between 5(th) and 6(th) decades of life and extremely rare in children. It is highly aggressive tumour and managed like glioblastoma multiforme. A 12-year-old female child presented with complaints of headache and vomiting from 15 d and blurring of vision from 3 d. Magnetic resonance imaging of brain shows heterogeneous mass in right parieto-occipital cortex. A right parieto-occipito-temporal craniotomy with complete excision of mass revealed a primary glioblastoma on histopathological investigation. Treatment consists of maximum surgical excision followed by adjuvant radiotherapy. The etiopathogenesis, treatment modalities and prognosis is discussed. The available literature is also reviewed. PMID:27672648

  10. Diffuse Scattering as an Aid to the Understanding of Polymorphism in Pharmaceuticals

    Science.gov (United States)

    Welberry, T. R.; Chan, E. J.; Goossens, D. J.; Heerdegen, A. P.

    2012-05-01

    Polymorphism occurs when the same molecular compound can crystallize in more than one distinct crystal structure. Its study is a field of great interest and activity. This is largely driven by its importance in the pharmaceutical industry, but polymorphism is also an issue in the pigments, dyes, and explosives industries. The polymorph formed by a compound generally exerts a strong influence on its solid-state properties. The polymorphic form of a drug molecule may affect the ease of manufacture and processing, shelf life, and most significantly the rate of uptake of the molecule by the human body. They can even vary in toxicity; one polymorph may be safe, while a second may be toxic. In this review of recently published work, we show how diffuse scattering experiments coupled with Monte Carlo (MC) computer modeling can aid in the understanding of polymorphism. Examples of the two common pharmaceuticals, benzocaine and aspirin, both of which are bimorphic, at ambient temperatures, are discussed.

  11. Finite element modeling and analysis of piezo-integrated composite structures under large applied electric fields

    Science.gov (United States)

    Rao, M. N.; Tarun, S.; Schmidt, R.; Schröder, K.-U.

    2016-05-01

    In this article, we focus on static finite element (FE) simulation of piezoelectric laminated composite plates and shells, considering the nonlinear constitutive behavior of piezoelectric materials under large applied electric fields. Under the assumptions of small strains and large electric fields, the second-order nonlinear constitutive equations are used in the variational principle approach, to develop a nonlinear FE model. Numerical simulations are performed to study the effect of material nonlinearity for piezoelectric bimorph and laminated composite plates as well as cylindrical shells. In comparison to the experimental investigations existing in the literature, the results predicted by the present model agree very well. The importance of the present nonlinear model is highlighted especially in large applied electric fields, and it is shown that the difference between the results simulated by linear and nonlinear constitutive FE models cannot be omitted.

  12. Remote light energy harvesting and actuation using shape memory alloy—piezoelectric hybrid transducer

    Science.gov (United States)

    Avirovik, Dragan; Kumar, Ashok; Bodnar, Robert J.; Priya, Shashank

    2013-05-01

    Shape memory alloys (SMAs) exhibit a memory effect which causes the alloy to return to its original shape when heated beyond the transformation temperature. In this study, we show that SMA can be heated remotely by laser and the resulting deformation can be converted into electricity through a piezoelectric bimorph. In addition, the laser actuated SMA deformation can also be used to provide controlled actuation. We provide experimental results demonstrating both the power harvesting and actuation behavior as a function of laser pulse rate. SMA used in this study exhibited higher absorption in the ultraviolet region which progressively decreased as the absorption wavelength increased. Raman analysis revealed TiO2 formation on the surface of SMA, whose concentration increased irreversibly with temperature. Negligible changes in the surface oxidation were detected in the working temperature range (<150 °C).

  13. Electrothermal MEMS parallel plate rotation for single-imager stereoscopic endoscopes.

    Science.gov (United States)

    Jang, Kyung-Won; Yang, Sung-Pyo; Baek, Seung-Hwan; Lee, Min-Suk; Park, Hyeon-Cheol; Seo, Yeong-Hyeon; Kim, Min H; Jeong, Ki-Hun

    2016-05-01

    This work reports electrothermal MEMS parallel plate-rotation (PPR) for a single-imager based stereoscopic endoscope. A thin optical plate was directly connected to an electrothermal MEMS microactuator with bimorph structures of thin silicon and aluminum layers. The fabricated MEMS PPR device precisely rotates an transparent optical plate up to 37° prior to an endoscopic camera and creates the binocular disparities, comparable to those from binocular cameras with a baseline distance over 100 μm. The anaglyph 3D images and disparity maps were successfully achieved by extracting the local binocular disparities from two optical images captured at the relative positions. The physical volume of MEMS PPR is well fit in 3.4 mm x 3.3 mm x 1 mm. This method provides a new direction for compact stereoscopic 3D endoscopic imaging systems.

  14. Realization of cantilever arrays for parallel proximity imaging

    International Nuclear Information System (INIS)

    This paper reports on the fabrication and characterisation of self-actuating, and self-sensing cantilever arrays for large-scale parallel surface scanning. Each cantilever is integrated with a sharp silicon tip, a thermal-driven bimorph actuator, and a piezoresistive deflection sensor. Thus, the tip to the sample distance can be controlled individually for each cantilever. A radius of the tips below 10 nm is obtained, which enables nanometre in-plane surface imaging by Angstrom resolution in vertical direction. The fabricated cantilever probe arrays are also applicable for large-area manipulation, sub-10 nm metrology, bottom-up synthesis, high-speed gas analysis, for different bio-applications like recognition of DNA, RNA, or various biomarkers of a single disease, etc.

  15. Diffuse Scattering as an Aid to the Understanding of Polymorphism in Pharmaceuticals

    Energy Technology Data Exchange (ETDEWEB)

    Welberry, T.R.; Chan, E.J.; Goossens, D.J.; Heerdegen, A.P. (ANU)

    2012-04-30

    Polymorphism occurs when the same molecular compound can crystallize in more than one distinct crystal structure. Its study is a field of great interest and activity. This is largely driven by its importance in the pharmaceutical industry, but polymorphism is also an issue in the pigments, dyes, and explosives industries. The polymorph formed by a compound generally exerts a strong influence on its solid-state properties. The polymorphic form of a drug molecule may affect the ease of manufacture and processing, shelf life, and most significantly the rate of uptake of the molecule by the human body. They can even vary in toxicity; one polymorph may be safe, while a second may be toxic. In this review of recently published work, we show how diffuse scattering experiments coupled with Monte Carlo (MC) computer modeling can aid in the understanding of polymorphism. Examples of the two common pharmaceuticals, benzocaine and aspirin, both of which are bimorphic, at ambient temperatures, are discussed.

  16. Self-(Un)rolling Biopolymer Microstructures: Rings, Tubules, and Helical Tubules from the Same Material.

    Science.gov (United States)

    Ye, Chunhong; Nikolov, Svetoslav V; Calabrese, Rossella; Dindar, Amir; Alexeev, Alexander; Kippelen, Bernard; Kaplan, David L; Tsukruk, Vladimir V

    2015-07-13

    We have demonstrated the facile formation of reversible and fast self-rolling biopolymer microstructures from sandwiched active-passive, silk-on-silk materials. Both experimental and modeling results confirmed that the shape of individual sheets effectively controls biaxial stresses within these sheets, which can self-roll into distinct 3D structures including microscopic rings, tubules, and helical tubules. This is a unique example of tailoring self-rolled 3D geometries through shape design without changing the inner morphology of active bimorph biomaterials. In contrast to traditional organic-soluble synthetic materials, we utilized a biocompatible and biodegradable biopolymer that underwent a facile aqueous layer-by-layer (LbL) assembly process for the fabrication of 2D films. The resulting films can undergo reversible pH-triggered rolling/unrolling, with a variety of 3D structures forming from biopolymer structures that have identical morphology and composition.

  17. Large-scale membrane transfer process: its application to single-crystal-silicon continuous membrane deformable mirror

    International Nuclear Information System (INIS)

    This paper describes a large-scale membrane transfer process developed for the construction of large-scale membrane devices via the transfer of continuous single-crystal-silicon membranes from one substrate to another. This technique is applied for fabricating a large stroke deformable mirror. A bimorph spring array is used to generate a large air gap between the mirror membrane and the electrode. A 1.9 mm × 1.9 mm × 2 µm single-crystal-silicon membrane is successfully transferred to the electrode substrate by Au–Si eutectic bonding and the subsequent all-dry release process. This process provides an effective approach for transferring a free-standing large continuous single-crystal-silicon to a flexible suspension spring array with a large air gap. (paper)

  18. Advances in Glomeromycota taxonomy and classification.

    Science.gov (United States)

    Oehl, Fritz; Sieverding, Ewald; Palenzuela, Javier; Ineichen, Kurt; Alves da Silva, Gladstone

    2011-12-01

    Concomitant morphological and molecular analyses have led to major breakthroughs in the taxonomic organization of the phylum Glomeromycota. Fungi in this phylum are known to form arbuscular mycorrhiza, and so far three classes, five orders, 14 families and 29 genera have been described. Sensulato, spore formation in 10 of the arbuscular mycorrhiza-forming genera is exclusively glomoid, one is gigasporoid, seven are scutellosporoid, four are entrophosporoid, two are acaulosporoid, and one is pacisporoid. Spore bimorphism is found in three genera, and one genus is associated with cyanobacteria. Here we present the current classification developed in several recent publications and provide a summary to facilitate the identification of taxa from genus to class level.

  19. Reliability study of Piezoelectric Structures Dedicated to Energy Harvesting by the Way of Blocking Force Investigation

    Science.gov (United States)

    Maaroufi, S.; Parrain, F.; Lefeuvre, E.; Boutaud, B.; Dal Molin, R.

    2015-12-01

    In this paper we propose an approach to study the reliability of piezoelectric structures and more precisely energy harvesting micro-devices dedicated to autonomous active medical implants (new generation pacemakers). The structure under test is designed as a bimorph piezoelectric cantilever with a seismic mass at its tip. Good understanding of material aging and mechanical failure is critical for this kind of system. To study the reliability and durability of the piezoelectric part we propose to establish a new accelerated methodology and an associated test bench where the environment and stimuli can be precisely controlled over a wide period of time. This will allow the identification of potential failure modes and the study of their impacts by the way of direct mechanical investigation based on stiffness and blocking force measurements performed periodically.

  20. Exploiting material softening in hard PZTs for resonant bandwidth enhancement

    Science.gov (United States)

    Leadenham, S.; Moura, A.; Erturk, A.

    2016-04-01

    Intentionally designed nonlinearities have been employed by several research groups to enhance the frequency bandwidth of vibration energy harvesters. Another type of nonlinear resonance behavior emerges from the piezoelectric constitutive behavior for high excitation levels and is manifested in the form of softening stiffness. This material nonlinearity does not result in the jump phenomenon in soft piezoelectric ceramics, e.g. PZT-5A and PZT-5H, due to their large internal dissipation. This paper explores the potential for wideband energy harvesting using a hard (relatively high quality factor) PZT-8 bimorph by exploiting its material softening. A wide range of base excitation experiments conducted for a set of resistive electrical loads confirms the frequency bandwidth enhancement.

  1. Theoretical analysis on shear-bending deflection of a ring-shape piezoelectric plate

    Directory of Open Access Journals (Sweden)

    Zejun Yu

    2016-02-01

    Full Text Available In this paper, the electromechanical coupling field in shear-bending mode for a ring-shape piezoelectric plate was theoretically established. According to the classical small bending elastic plate theory and piezoelectric constitutive equations, the analytical solution to the bending deformation of the piezo-actuator under electric field and a concentrated or uniformly distributed mechanical load was achieved. The mechanism for generating bending deformation is attributed to axisymmetric shear strain, which further induces the bending deformation of the single ring-shape piezoelectric plate. This mechanism is significant different from that of piezoelectric bimorph or unimorph actuators reported before. Our analysis offers guidance for the optimum design of a ring-shape shear-bending piezo-actuator.

  2. Enhancement of Optical Adaptive Sensing by Using a Dual-Stage Seesaw-Swivel Actuator with a Tunable Vibration Absorber

    Directory of Open Access Journals (Sweden)

    Po-Chien Chou

    2011-05-01

    Full Text Available Technological obstacles to the use of rotary-type swing arm actuators to actuate optical pickup modules in small-form-factor (SFF disk drives stem from a hinge’s skewed actuation, subsequently inducing off-axis aberrations and deteriorating optical quality. This work describes a dual-stage seesaw-swivel actuator for optical pickup actuation. A triple-layered bimorph bender made of piezoelectric materials (PZTs is connected to the suspension of the pickup head, while the tunable vibration absorber (TVA unit is mounted on the seesaw swing arm to offer a balanced force to reduce vibrations in a focusing direction. Both PZT and TVA are designed to satisfy stable focusing operation operational requirements and compensate for the tilt angle or deformation of a disc. Finally, simulation results verify the performance of the dual-stage seesaw-swivel actuator, along with experimental procedures and parametric design optimization confirming the effectiveness of the proposed system.

  3. Thermo-Electro-Mechanical Analysis of a Curved Functionally Graded Piezoelectric Actuator with Sandwich Structure

    Directory of Open Access Journals (Sweden)

    Liying Jiang

    2011-12-01

    Full Text Available In this work, the problem of a curved functionally graded piezoelectric (FGP actuator with sandwich structure under electrical and thermal loads is investigated. The middle layer in the sandwich structure is functionally graded with the piezoelectric coefficient g31 varying continuously along the radial direction of the curved actuator. Based on the theory of linear piezoelectricity, analytical solutions are obtained by using Airy stress function to examine the effects of material gradient and heat conduction on the performance of the curved actuator. It is found that the material gradient and thermal load have significant influence on the electroelastic fields and the mechanical response of the curved FGP actuator. Without the sacrifice of actuation deflection, smaller internal stresses are generated by using the sandwich actuator with functionally graded piezoelectric layer instead of the conventional bimorph actuator. This work is very helpful for the design and application of curved piezoelectric actuators under thermal environment.

  4. 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.

  5. Electrothermally actuated tip-tilt-piston micromirror with integrated varifocal capability.

    Science.gov (United States)

    Morrison, Jessica; Imboden, Matthias; Little, Thomas D C; Bishop, D J

    2015-04-01

    MEMS micromirrors have proven to be very important optical devices with applications ranging from steerable mirrors for switches and cross-connects to spatial light modulators for correcting optical distortions. Usually beam steering and focusing are done with different MEMS devices and tilt angles in excess of 10 degrees are seldom obtained. Here we describe a single MEMS device that combines tip/tilt, piston mode and varifocal capability into a single, low cost device with very large tilt angles. Our device consists of a 400 micron diameter mirror driven with thermal bimorphs. We have demonstrated deflection angles of ± 40 degrees along both axes, a tunable focal length which varies between -0.48 mm to + 20.5 mm and a piston mode range of 300 microns - four separately controllable degrees of freedom in a single device. Potential applications range from smart lighting to optical switches and devices for telecom systems. PMID:25968784

  6. Characterization of a high-power piezoelectric energy-scavenging device based on PMN-PT piezoelectric single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Moon, S. E.; Lee, S. K.; Lee, Y. G.; Kim, K. M.; Yang, Y. S.; Yang, W. S.; Kim, J. [Electronics and Telecommunications Research Institute, Daejeon (Korea, Republic of)

    2012-01-15

    In this paper, we present the calculations and the results for vibration-energy-scavenging performances based on a piezoelectric single-crystal beam. Using the measured mechanical damping ratio and electro-mechanical coupling coefficient of a novel cantilever structure device, we calculated the output performances and compared them with the measured results. A device based on a bimorph cantilever structure with a proof mass was designed to have a natural resonance frequency of about 60 Hz, and the energy-scavenging capability of piezoelectric single crystal was measured. The results showed that several tens of AC volts and a few milliwatts power were achieved under a 0.1 g{sub rms} vibration condition. Also using this device and a commercial power management circuit, we performed Li-ion battery charging experiment.

  7. Monolithically integrated cantilevers with self-aligned tips for wavelength tuning in a photonic crystal cavity-based channel-drop filter

    International Nuclear Information System (INIS)

    A technology to monolithically integrate micro-bimorph cantilevers equipped with tips that are self-aligned with respect to the holes of a 2D photonic crystal cavity-based channel-drop filter is presented. On electrostatic actuation, the tips move into the holes and provide electromechano-optical modulation of light. The technology allows the fabrication of tips on specific photonic crystal holes by controlling the hole diameter and the sacrificial layer thickness. The integrated device is both mechanically and optically characterized. A 180 pm wavelength shift at the first band edge of the photonic crystal cavity-based channel-drop filter is measured on the application of a 2 V dc voltage to the cantilever. This CMOS-compatible device is designed to operate in the C-band of the telecommunication wavelengths and constitutes a promising candidate for future integrated all-optical devices

  8. Continuous Trailing-Edge Flaps for Primary Flight Control of a Helicopter Main Rotor

    Science.gov (United States)

    Thornburgh, Robert P.; Kreshock, Andrew R.; Wilbur, Matthew L.; Sekula, Martin K.; Shen, Jinwei

    2014-01-01

    The use of continuous trailing-edge flaps (CTEFs) for primary flight control of a helicopter main rotor is studied. A practical, optimized bimorph design with Macro-Fiber Composite actuators is developed for CTEF control, and a coupled structures and computational fluid dynamics methodology is used to study the fundamental behavior of an airfoil with CTEFs. These results are used within a comprehensive rotorcraft analysis model to study the control authority requirements of the CTEFs when utilized for primary flight control of a utility class helicopter. A study of the effect of blade root pitch index (RPI) on CTEF control authority is conducted, and the impact of structural and aerodynamic model complexity on the comprehensive analysis results is presented. The results show that primary flight control using CTEFs is promising; however, a more viable option may include the control of blade RPI, as well.

  9. Investigations of electronic amplifiers supplying a piezobimorph actuator

    Science.gov (United States)

    Milecki, Andrzej; Regulski, Roman

    2016-10-01

    Piezoelectric bending actuators, also known as bimorphs, are characterized by very good dynamic properties and by displacements in a range of a few millimeters. Therefore these actuators are used in a wide range of applications. However their usage is limited because they require supplying amplifiers with output voltage of about 200 V, which are rather expensive. This paper presents investigation results of such amplifiers with high voltage output. The model of a piezobending actuator is proposed and implemented in Matlab-Simulink software in order to simulate the behavior of the actuator supplied by the amplifiers. The simulation results are presented and compared with investigation results of high voltage amplifier used for supplying a piezoactuator. The influence of current limitation of operational amplifier on the actuator current is tested. Finally, a low cost audio power amplifier is proposed to control the piezobender actuator (as a cheaper alternative to the high-voltage amplifier) and its investigations results are presented in the paper.

  10. Electrothermal MEMS parallel plate rotation for single-imager stereoscopic endoscopes.

    Science.gov (United States)

    Jang, Kyung-Won; Yang, Sung-Pyo; Baek, Seung-Hwan; Lee, Min-Suk; Park, Hyeon-Cheol; Seo, Yeong-Hyeon; Kim, Min H; Jeong, Ki-Hun

    2016-05-01

    This work reports electrothermal MEMS parallel plate-rotation (PPR) for a single-imager based stereoscopic endoscope. A thin optical plate was directly connected to an electrothermal MEMS microactuator with bimorph structures of thin silicon and aluminum layers. The fabricated MEMS PPR device precisely rotates an transparent optical plate up to 37° prior to an endoscopic camera and creates the binocular disparities, comparable to those from binocular cameras with a baseline distance over 100 μm. The anaglyph 3D images and disparity maps were successfully achieved by extracting the local binocular disparities from two optical images captured at the relative positions. The physical volume of MEMS PPR is well fit in 3.4 mm x 3.3 mm x 1 mm. This method provides a new direction for compact stereoscopic 3D endoscopic imaging systems. PMID:27137580

  11. Energy harvesting in a quad-stable harvester subjected to random excitation

    Directory of Open Access Journals (Sweden)

    Zhi-yong Zhou

    2016-02-01

    Full Text Available In response to the defects of bi-stable energy harvester (BEH, we develop a novel quad-stable energy harvester (QEH to improve harvesting efficiency. The device is made up of a bimorph cantilever beam having a tip magnet and three external fixed magnets. By adjusting the positions of the fixed magnets and the distances between the tip magnet and the fixed ones, the quad-stable equilibrium positions can emerge. The potential energy shows that the barriers of the QEH are lower than those of the BEH for the same separation distance. Experiment results reveal that the QEH can realize snap-through easier and make a dense snap-through in response under random excitation. Moreover, its strain and voltage both become large for snap-through between the nonadjacent stable positions. There exists an optimal separation distance for different excitation intensities.

  12. NASA Tech Briefs, May 2003

    Science.gov (United States)

    2003-01-01

    Topics covered include: Using Diffusion Bonding in Making Piezoelectric Actuators; Wireless Temperature-Monitoring System; Analog Binaural Circuits for Detecting and Locating Leaks; Mirrors Containing Biomimetic Shape-Control Actuators; Surface-Micromachined Planar Arrays of Thermopiles; Cascade Back-Propagation Learning in Neural Networks; Perovskite Superlattices as Tunable Microwave Devices; Rollable Thin-Shell Nanolaminate Mirrors; Flight Tests of a Ministick Controller in an F/A-18 Airplane; Piezoelectrically Actuated Shutter for High Vacuum; Bio-Inspired Engineering of Exploration Systems; Microscope Cells Containing Multiple Micromachined Wells; Electrophoretic Deposition for Fabricating Microbatteries; Integrated Arrays of Ion-Sensitive Electrodes; Model of Fluidized Bed Containing Reacting Solids and Gases; Membrane Mirrors With Bimorph Shape Actuators; Using Fractional Clock-Period Delays in Telemetry Arraying; Developing Generic Software for Spacecraft Avionics; Numerical Study of Pyrolysis of Biomass in Fluidized Beds; and Assessment of Models of Chemically Reacting Granular Flows.

  13. Harvested power and sensitivity analysis of vibrating shoe-mounted piezoelectric cantilevers

    Science.gov (United States)

    Moro, L.; Benasciutti, D.

    2010-11-01

    This paper presents a preliminary investigation on energy harvesting from human walking via piezoelectric vibrating cantilevers. Heel accelerations during human gait are established by correlating data gathered from the literature with direct experimental measurements. All the observed relevant features are synthesized in a typical (standard) acceleration signal, used in subsequent numerical simulations. The transient electromechanical response and the harvested power of a shoe-mounted bimorph cantilever excited by the standard acceleration signal is computed by numerical simulations and compared with measurements on a real prototype. A sensitivity analysis is finally developed to estimate the mean harvested power for a wide range of scavenger configurations. Acceptability criteria based on imposed geometrical constraints and resistance strength limits (e.g. fatigue limit) are also established. This analysis allows a quick preliminary screening of harvesting performance of different scavenger configurations.

  14. An Exact Analytical Solution to Exponentially Tapered Piezoelectric Energy Harvester

    Directory of Open Access Journals (Sweden)

    H. Salmani

    2015-01-01

    Full Text Available It has been proven that tapering the piezoelectric beam through its length optimizes the power extracted from vibration based energy harvesting. This phenomenon has been investigated by some researchers using semianalytical, finite element and experimental methods. In this paper, an exact analytical solution is presented to calculate the power generated from vibration of exponentially tapered unimorph and bimorph with series and parallel connections. The mass normalized mode shapes of the exponentially tapered piezoelectric beam with tip mass are implemented to transfer the proposed electromechanical coupled equations into modal coordinates. The steady states harmonic solution results are verified both numerically and experimentally. Results show that there exist values for tapering parameter and electric resistance in a way that the output power per mass of the energy harvester will be maximized. Moreover it is concluded that the electric resistance must be higher than a specified value for gaining more power by tapering the beam.

  15. Vibration energy harvester with sustainable power based on a single-crystal piezoelectric cantilever array.

    Science.gov (United States)

    Kim, Moonkeun; Lee, Sang-Kyun; Ham, Yong-Hyun; Yang, Yil Suk; Kwon, Jong-Kee; Kwon, Kwang-Ho

    2012-08-01

    We designed and fabricated a bimorph cantilever array for sustainable power with an integrated Cu proof mass to obtain additional power and current. We fabricated a cantilever system using single-crystal piezoelectric material and compared the calculations for single and arrayed cantilevers to those obtained experimentally. The vibration energy harvester had resonant frequencies of 60.4 and 63.2 Hz for short and open circuits, respectively. The damping ratio and quality factor of the cantilever device were 0.012 and 41.66, respectively. The resonant frequency at maximum average power was 60.8 Hz. The current and highest average power of the harvester array were found to be 0.728 mA and 1.61 mW, respectively. The sustainable maximum power was obtained after slightly shifting the short-circuit frequency. In order to improve the current and power using an array of cantilevers, we also performed energy conversion experiments. PMID:22962737

  16. Modeling a novel energy harvester working in Lame mode

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhuming; Mei, Jie [Multidisciplinary Nanotechnology Centre, College of Engineering, Swansea University, SA2 8PP (United Kingdom); Li, Lijie, E-mail: L.Li@swansea.ac.uk [Multidisciplinary Nanotechnology Centre, College of Engineering, Swansea University, SA2 8PP (United Kingdom)

    2012-04-30

    A new square shaped piezoelectric bimorph structure for energy scavenging purposes has been proposed and simulated. It is derived from theoretical analysis that the output power of the structure is proportional to the value of the resonant frequency. The device working in Lame mode has a much higher resonant frequency of 2.39 MHz than devices working in ordinary bending modes, which is expected to significantly increase the energy output of radioisotope power generators (RPGs). The results of static analysis and dynamic response show that output voltage is linear with the applied load; the output power is quadratic with the applied load. -- Highlights: ► We present a new mechanical to electrical energy harvester. ► The energy harvester is square shaped and operated in Lame mode. ► The proposed design has very high resonant frequency. ► It is expected the device has promising application in radioisotope power generators.

  17. A piezoelectric energy harvester with increased bandwidth based on beam flexural vibrations in perpendicular directions.

    Science.gov (United States)

    Li, Peng; Jin, Feng; Yang, Jiashi

    2013-10-01

    We propose a new structure for piezoelectric energy harvesters. It consists of an elastic beam with two pairs of piezoelectric films operating with the fundamental flexural modes in perpendicular directions. A one-dimensional model is developed and used to analyze the proposed structure. The output power density is calculated and examined. Results show that, with simultaneous flexural motions in two perpendicular directions, the output power has two peaks close to each other resulting from the two fundamental flexural resonances. The distance between the two peaks can be adjusted through design to make the two peaks merge into one wide peak. Hence, the frequency bandwidth through which energy can be harvested is roughly doubled when compared with conventional beam bimorph energy harvesters operating with flexural motion in one direction and one resonance only. PMID:24081271

  18. Modeling and vibration control of an active membrane mirror

    Science.gov (United States)

    Ruggiero, Eric J.; Inman, Daniel J.

    2009-09-01

    The future of space satellite technology lies in ultra-large mirrors and radar apertures for significant improvements in imaging and communication bandwidths. The availability of optical-quality membranes drives a parallel effort for structural models that can capture the dominant dynamics of large, ultra-flexible satellite payloads. Unfortunately, the inherent flexibility of membrane mirrors wreaks havoc with the payload's on-orbit stability and maneuverability. One possible means of controlling these undesirable dynamics is by embedding active piezoelectric ceramics near the boundary of the membrane mirror. In doing so, active feedback control can be used to eliminate detrimental vibration, perform static shape control, and evaluate the health of the structure. The overall motivation of the present work is to design a control system using distributed bimorph actuators to eliminate any detrimental vibration of the membrane mirror. As a basis for this study, a piezoceramic wafer was attached in a bimorph configuration near the boundary of a tensioned rectangular membrane sample. A finite element model of the system was developed to capture the relevant system dynamics from 0 to 300 Hz. The finite element model was compared against experimental results, and fair agreement found. Using the validated finite element models, structural control using linear quadratic regulator control techniques was then used to numerically demonstrate effective vibration control. Typical results show that less than 12 V of actuation voltage is required to eliminate detrimental vibration of the membrane samples in less than 15 ms. The functional gains of the active system are also derived and presented. These spatially descriptive control terms dictate favorable regions within the membrane domain for placing sensors and can be used as a design guideline for structural control applications. The results of the present work demonstrate that thin plate theory is an appropriate modeling

  19. Nano-optical conveyor belt with waveguide-coupled excitation.

    Science.gov (United States)

    Wang, Guanghui; Ying, Zhoufeng; Ho, Ho-pui; Huang, Ying; Zou, Ningmu; Zhang, Xuping

    2016-02-01

    We propose a plasmonic nano-optical conveyor belt for peristaltic transport of nano-particles. Instead of illumination from the top, waveguide-coupled excitation is used for trapping particles with a higher degree of precision and flexibility. Graded nano-rods with individual dimensions coded to have resonance at specific wavelengths are incorporated along the waveguide in order to produce spatially addressable hot spots. Consequently, by switching the excitation wavelength sequentially, particles can be transported to adjacent optical traps along the waveguide. The feasibility of this design is analyzed using three-dimensional finite-difference time-domain and Maxwell stress tensor methods. Simulation results show that this system is capable of exciting addressable traps and moving particles in a peristaltic fashion with tens of nanometers resolution. It is the first, to the best of our knowledge, report about a nano-optical conveyor belt with waveguide-coupled excitation, which is very important for scalability and on-chip integration. The proposed approach offers a new design direction for integrated waveguide-based optical manipulation devices and its application in large scale lab-on-a-chip integration.

  20. Mixing and Transport in the Small Intestine: A Lattice-Boltzmann Model

    Science.gov (United States)

    Banco, Gino; Brasseur, James; Wang, Yanxing; Aliani, Amit; Webb, Andrew

    2007-11-01

    The two primary functions of the small intestine are absorption of nutrients into the blood stream and transport of material along the gut for eventual evacuation. The primary transport mechanism is peristalsis. The time scales for absorption, however, rely on mixing and transport of molecules between the bulk flow and epithelial surface. Two basic motions contribute to mixing: peristalsis and repetitive segmental contraction of short segments of the gut. In this study we evaluate the relative roles of peristalsis vs. segmental contraction on the degree of mixing and time scales of nutrient transport to the epithelium using a two-dimensional model of flow and mixing in the small intestine. The model uses the lattice-Boltzmann framework with second-order moving boundary conditions and passive scalar (Sc = 10). Segmental and peristaltic contractions were parameterized using magnetic resonance imaging data from rat models. The Reynolds numbers (1.9), segment lengths (33 mm), max radii (2.75 mm) and occlusion ratios (0.33) were matched for direct comparison. Mixing is quantified by the rate of dispersion of scalar from an initial concentration in the center of the segment. We find that radial mixing is more rapid with segmental than peristaltic motion, that radial dispersion is much more rapid than axial, and that axial is comparable between the motions.

  1. Automation of cells of radiopharmaceuticals production

    International Nuclear Information System (INIS)

    The 67Ga is an important radiopharmaceutical used to identify inflammatory processes in chronic illnesses, diagnosis by image of tumors in soft tissues and the possibility to evaluate the result for therapeutic intervention. In the present work a module of 67Ga processing was developed with the objective to reduce the interventions in the hot cell, in order to avoid oxidation caused by metallic materials, and consuming in hoses of the peristaltic pumps, that release residues that blocked the valves used in the process. With materials such as: acrylic, PVC, PEEK e teflon and they are used vacuum as method (way) of fluid transferences instead of peristaltic pump in the majority of the procedures, with this improvements the system can make shorter the lengths of transference hoses, increasing the yield in the process with less interventions for maintenance and time exposure of the workers, guaranteeing the quality and reducing the time of the processing. using a mobile system for displacement of the processing module making in the cleanness and maintenance of the cell that works with radioactive material. Reducing the time of exposure dose of the workers in compliance with RDC-17 of ANVISA, which ruling the Good Manufacturing Practice Procedures. (author)

  2. A flow-batch analyzer with piston propulsion applied to automatic preparation of calibration solutions for Mn determination in mineral waters by ET AAS.

    Science.gov (United States)

    Almeida, Luciano F; Vale, Maria G R; Dessuy, Morgana B; Silva, Márcia M; Lima, Renato S; Santos, Vagner B; Diniz, Paulo H D; Araújo, Mário C U

    2007-10-31

    The increasing development of miniaturized flow systems and the continuous monitoring of chemical processes require dramatically simplified and cheap flow schemes and instrumentation with large potential for miniaturization and consequent portability. For these purposes, the development of systems based on flow and batch technologies may be a good alternative. Flow-batch analyzers (FBA) have been successfully applied to implement analytical procedures, such as: titrations, sample pre-treatment, analyte addition and screening analysis. In spite of its favourable characteristics, the previously proposed FBA uses peristaltic pumps to propel the fluids and this kind of propulsion presents high cost and large dimension, making unfeasible its miniaturization and portability. To overcome these drawbacks, a low cost, robust, compact and non-propelled by peristaltic pump FBA is proposed. It makes use of a lab-made piston coupled to a mixing chamber and a step motor controlled by a microcomputer. The piston-propelled FBA (PFBA) was applied for automatic preparation of calibration solutions for manganese determination in mineral waters by electrothermal atomic-absorption spectrometry (ET AAS). Comparing the results obtained with two sets of calibration curves (five by manual and five by PFBA preparations), no significant statistical differences at a 95% confidence level were observed by applying the paired t-test. The standard deviation of manual and PFBA procedures were always smaller than 0.2 and 0.1mugL(-1), respectively. By using PFBA it was possible to prepare about 80 calibration solutions per hour. PMID:19073119

  3. A role for compromise: synaptic inhibition and electrical coupling interact to control phasing in the leech heartbeat CPG

    Directory of Open Access Journals (Sweden)

    Adam L Weaver

    2010-07-01

    Full Text Available How can flexible phasing be generated by a central pattern generator (CPG? To address this question, we have extended an existing model of the leech heartbeat CPG’s timing network to construct a model of the CPG core and explore how appropriate phasing is set up by parameter variation. Within the CPG, the phasing among premotor interneurons switches regularly between two well-defined states - synchronous and peristaltic. To reproduce experimentally observed phasing, we varied the strength of inhibitory synaptic and excitatory electrical input from the timing network to follower premotor interneurons. Neither inhibitory nor electrical input alone was sufficient to produce proper phasing on both sides, but instead a balance was required. Our model suggests that the different phasing of the two sides arises because the inhibitory synapses and electrical coupling oppose one another on one side (peristaltic and reinforce one another on the other (synchronous. Our search of parameter space defined by the strength of inhibitory synaptic and excitatory electrical input strength led to a CPG model that well approximates the experimentally observed phase relations. The strength values derived from this analysis constitute model predictions that we tested by measurements made in the living system. Further, variation of the intrinsic properties of follower interneurons showed that they too systematically influence phasing. We show further that a combination of inhibitory synaptic and excitatory electrical input interacting with neuronal intrinsic properties can flexibly generate a variety of phase relations so that almost any phasing is possible.

  4. An approach to the capsule endoscopic robot with active drive motion

    Institute of Scientific and Technical Information of China (English)

    Da-qiang GU; Yong ZHOU

    2011-01-01

    Commercialized capsule-type endoscopes move passively by peristaltic waves (and gravity), which makes it difficult for doctors to diagnose the areas of interest more thoroughly and actively. To resolve this problem of passivity, it is necessary to find a special locomotion principle, which fits the gastrointestinal (GI) tract. In this paper, a legged locomotive mechanism with shape memory alloy (SMA) actuation based on the peristaltic principle is proposed, and then the structure of the locomotion mechanism is introduced. Based on the preliminary results, the design, modeling, and fabrication of an SMA microactuation concept for application in an endoscopic capsule are given, as well as the SMA spring and legged component design, which is the core section of the system design. We used the pseudo-rigid-body model (PRBM) to analyze nonlinear and large deflections of the SMA legged component. Thus, a prototype endoscope with an SMA spring and six legged components was designed and fabricated. It is 15 mm in diameter and 33 mm in total length, with a hollow space to house other parts needed for endoscopy such as a camera, a radio frequency (RF) module, and sensors. During testing, the locomotive mechanism was effective in a plastic tube environment.

  5. Hyperpolarised sup 3 He gas production for magnetic resonance imaging of the human air ways

    CERN Document Server

    Fichele, S

    2002-01-01

    This thesis describes the experimental techniques, and methods employed in hyperpolarised sup 3 He gas production and magnetic resonance imaging of the human air-ways, using spin-echo sequences and MR tagging techniques. An in-house polariser utilising the metastability optical pumping technique was constructed. The main results of this work are concerned with engineering difficulties involved in compressing HP sup 3 He and a large proportion of this PhD thesis details the design, construction, and performance of an in-house built peristaltic compressor. In preliminary imaging experiments using RARE, high signal to noise projection images of the lungs were acquired using less than 0.5 cm sup 3 (STP) of purely polarised HP gas. Later, increased HP gas quantities (typically 10 cm sup 3) were obtained by employing the peristaltic compressor. Consequently we could acquire 10 mm thick slices spanning the entire lung following a single sup 3 He gas bolus administration. Finally, the first results using MR tagging t...

  6. Measurements of Gastric Emptying by Biomagnetic Techniques

    Science.gov (United States)

    Vázquez, L. A.; Sosa, M.; Córdova, T.; Vargas, F. M.; Huerta, M. R.

    2006-09-01

    In the present work a new method to measure the average time of gastric emptying by using a magnetic tracer is showed, this work shows the application of foundations of the electromagnetic theory in the study of the gastrointestinal system. The presented technique is relatively cheap and can be used it to diagnose of diseases, is a noninvasive method, is a technique that does not use ionizing radiation. In this investigation was possible to measure the average time of gastric emptying with a very high precision. In this investigation measurements of 10 healthy volunteers were made, and an average time of gastric emptying of 36.45 minutes in the space of the time was obtained, in addition with the analysis to the signal by means of the use of a pass-band filter it was possible to measure the peristaltic frequencies of the stomach and an average time of 37.24 minutes in the space of frequencies. With this technique it is possible to obtain data of the walls of the stomach. A peristaltic frequency of 2.79 was obtained cpm (cycles per minute).

  7. Environmental DNA sampling protocol - filtering water to capture DNA from aquatic organisms

    Science.gov (United States)

    Laramie, Matthew B.; Pilliod, David S.; Goldberg, Caren S.; Strickler, Katherine M.

    2015-09-29

    Environmental DNA (eDNA) analysis is an effective method of determining the presence of aquatic organisms such as fish, amphibians, and other taxa. This publication is meant to guide researchers and managers in the collection, concentration, and preservation of eDNA samples from lentic and lotic systems. A sampling workflow diagram and three sampling protocols are included as well as a list of suggested supplies. Protocols include filter and pump assembly using: (1) a hand-driven vacuum pump, ideal for sample collection in remote sampling locations where no electricity is available and when equipment weight is a primary concern; (2) a peristaltic pump powered by a rechargeable battery-operated driver/drill, suitable for remote sampling locations when weight consideration is less of a concern; (3) a 120-volt alternating current (AC) powered peristaltic pump suitable for any location where 120-volt AC power is accessible, or for roadside sampling locations. Images and detailed descriptions are provided for each step in the sampling and preservation process.

  8. Environmental DNA sampling protocol - filtering water to capture DNA from aquatic organisms

    Science.gov (United States)

    Laramie, Matthew B.; Pilliod, David S.; Goldberg, Caren S.; Strickler, Katherine M.

    2015-01-01

    Environmental DNA (eDNA) analysis is an effective method of determining the presence of aquatic organisms such as fish, amphibians, and other taxa. This publication is meant to guide researchers and managers in the collection, concentration, and preservation of eDNA samples from lentic and lotic systems. A sampling workflow diagram and three sampling protocols are included as well as a list of suggested supplies. Protocols include filter and pump assembly using: (1) a hand-driven vacuum pump, ideal for sample collection in remote sampling locations where no electricity is available and when equipment weight is a primary concern; (2) a peristaltic pump powered by a rechargeable battery-operated driver/drill, suitable for remote sampling locations when weight consideration is less of a concern; (3) a 120-volt alternating current (AC) powered peristaltic pump suitable for any location where 120-volt AC power is accessible, or for roadside sampling locations. Images and detailed descriptions are provided for each step in the sampling and preservation process.

  9. [Erythrocyte removal from bone marrow by density gradient separation using the COBE 2991 cell processor with the triple-bag processing set].

    Science.gov (United States)

    Cappellesso-Fleury, S; Rage, C; Tschaggeny, F; Gaudé, J; Gomez, M; Bourin, P

    2009-03-01

    ABO-incompatible bone marrow transplantation requires red blood cell depletion. Lots of laboratory adopted the technique of density gradient centrifugation (Ficoll-hypaque) using the COBE 2991 cell processor with simple-bag processing set. However, tubing of this set is not adapted to the currently available peristaltic pumps. Moreover, two other sets are required: one for the buffy-coat and one for postgradient cell washing. We developed a method using triple-bag processing set to conduct whole-step procedure (concentration, Ficoll and washing). Peristaltic PVC tubing is provided in one line of the set allowing a safe processing without several connections thus reducing risks of microbial contamination. First, we used buffy-coat of total blood for training, then, we carried out red cell depletion of healthy bone marrow donors. The red blood cell depletion was 97.9+/-1.1% and CD34+ recovery was 89.6+/-8.7%. These results are very close to those obtained with the simple-bag set (red cell depletion.=94.0+/-6.8% and CD34+ recovery=95.9+/-20.3%). We conclude that the triple-bag system, very little used in France, is practical, simplified the manipulation and is more safety than the simple-bag set.

  10. A nanoliter-scale open chemical reactor.

    Science.gov (United States)

    Galas, Jean-Christophe; Haghiri-Gosnet, Anne-Marie; Estévez-Torres, André

    2013-02-01

    An open chemical reactor is a container that exchanges matter with the exterior. Well-mixed open chemical reactors, called continuous stirred tank reactors (CSTR), have been instrumental for investigating the dynamics of out-of-equilibrium chemical processes, such as oscillations, bistability, and chaos. Here, we introduce a microfluidic CSTR, called μCSTR, that reduces reagent consumption by six orders of magnitude. It consists of an annular reactor with four inlets and one outlet fabricated in PDMS using multi-layer soft lithography. A monolithic peristaltic pump feeds fresh reagents into the reactor through the inlets. After each injection the content of the reactor is continuously mixed with a second peristaltic pump. The efficiency of the μCSTR is experimentally characterized using a bromate, sulfite, ferrocyanide pH oscillator. Simulations accounting for the digital injection process are in agreement with experimental results. The low consumption of the μCSTR will be advantageous for investigating out-of-equilibrium dynamics of chemical processes involving biomolecules. These studies have been scarce so far because a miniaturized version of a CSTR was not available.

  11. [Vaginal eviscentration with secondary strangulation of small bowel].

    Science.gov (United States)

    Gembal, Piotr; Grzegorczyk, Wiesław; Grabowski, Bogumił; Milik, Krzysztof; Pajak, Marek; Bielecki, Krzysztof

    2007-01-01

    A case of 81 year old patient with eviscentration through vagina with a strangulation of small bowel was described. The woman was treated gynecologically and underwent surgery previously. The eviscentration occurred 21 months after last surgery and was connected with high abdominal pressure during defecation. Woman was qualified to an urgent laparotomy, and the hole about 15 mm length in vaginal posterior vault was found. Through the hole passed small bowel which was strangulated. The bowel was removed to the abdominal cavity and during its control no necrosis was found. The color and vascularity return to normal and right peristaltic was noticed. The hole in parietal peritoneum was closed by a continuous suture. The hole in vagina was also closed by the continuous suture from the perineal side. Woman in good general condition was discharged from hospital in the 13th day after surgery. PMID:18540188

  12. Tubular Heart Pumping Mechanisms in Ciona Intestinalis

    Science.gov (United States)

    Battista, Nicholas; Miller, Laura

    2015-11-01

    In vertebrate embryogenesis, the first organ to form is the heart, beginning as a primitive heart tube. However, many invertebrates have tubular hearts from infancy through adulthood. Heart tubes have been described as peristaltic and impedance pumps. Impedance pumping assumes a single actuation point of contraction, while traditional peristalsis assumes a traveling wave of actuation. In addition to differences in flow, this inherently implies differences in the conduction system. It is possible to transition from pumping mechanism to the other with a change in the diffusivity of the action potential. In this work we consider the coupling between the fluid dynamics and electrophysiology of both mechanisms, within a basal chordate, the tunicate. Using CFD with a neuro-mechanical model of tubular pumping, we discuss implications of the both mechanisms. Furthermore, we discuss the implications of the pumping mechanism on evolution and development.

  13. Analysis of tecniques for measurement of the size distribution of solid particles

    Directory of Open Access Journals (Sweden)

    F. O. Arouca

    2005-03-01

    Full Text Available Determination of the size distribution of solid particles is fundamental for analysis of the performance several pieces of equipment used for solid-fluid separation. The main objective of this work is to compare the results obtained with two traditional methods for determination of the size grade distribution of powdery solids: the gamma-ray attenuation technique (GRAT and the LADEQ test tube technique. The effect of draining the suspension in the two techniques used was also analyzed. The GRAT can supply the particle size distribution of solids through the monitoring of solid concentration in experiments on batch settling of diluted suspensions. The results show that use of the peristaltic pump in the GRAT and the LADEQ methods produced a significant difference between the values obtained for the parameters of the particle size model.

  14. Straight ileo-anal anastomosis with myectomy as an alternative to ileal pouch-anal anastomosis in restorative proctocolectomy.

    Science.gov (United States)

    Landi, E; Landa, L; Fianchini, A; Marmorale, C; Piloni, V

    1994-04-01

    Restorative proctocolectomy with various types of reservoir is widely used in the elective surgery of ulcerative colitis and familial adenomatous polyposis. Both, advantages and disadvantages of this procedure are well known and documented. Straight ileo-anal anastomosis (IAA) yields unsatisfactory clinical results due to the lack of storage capacity of the distal ileum and the frequency of bowel movements related to high pressure ileal waves. In an attempt to create an alternative to the above procedures, we have performed a straight ileo-anal anastomosis with two rectangular (10 cm x 1 cm) myectomies down to 2 cm, above the anastomotic line. The two myectomies are spaced at 120 degrees to each other and to the mesenteric border of the ileal loop. The rationale of this approach is to reduce the peristaltic drive of the ileum by weakening the muscular wall. This study presents the results in three patients operated on with this new method in the last year.

  15. Propulsor pneumático versátil e isento de pulsação para sistemas de análise em fluxo

    Directory of Open Access Journals (Sweden)

    Matos Renato C.

    2001-01-01

    Full Text Available Aquarium air pumps are proposed and evaluated as pneumatic liquid propulsion devices for flow injection and continuos flow analysis (FIA and CFA systems. This kind of pump is widely available at a very low cost and it can sustain a pressure around of 4 psi (0.28 bar indefinitely. By applying this air pressure onto a solution contained in a reservoir flask, it is possible to reach flow rates of up to 12.5 mL min-1 for circuits comprising reactors, made from 0.8 i.d. tubing with a length of 100 cm. The precise adjustment of flow rate below the maximum one can be made with a simplified needle valve or inserting in series a short length of capillary tube. The absence of flow pulsation is a definite advantage in comparison with peristaltic pumps, especially when amperometric detection is elected, as confirmed experimentally in FIA and CF applications.

  16. Uso da pressão gerada por uma coluna de água para controle da vazão em sistemas de análises em fluxo The use of pressure generated by a water column to control flow rates in flow analysis systems

    Directory of Open Access Journals (Sweden)

    Wallans T. P. dos Santos

    2007-01-01

    Full Text Available This work presents a new approach to control the flow rate in hydrodynamic flow experiments. The combination of air pressure generated by an aquarium air pump and the pressure generated by a water column were used for this purpose. This device supports a stable flow rate without pulsation for a long period of time. Furthermore, the flow rate can be easily controlled at various values in one or more streams. The performance of this approach was investigated using Fe(CN6(4- solutions in flowing systems using amperometric and voltammetric detection in wall-jet configuration. The results showed that the performance of the proposed device was better than a commercial peristaltic pump. It suggests that this approach can be used successfully in flow analysis systems.

  17. The neuropathic oesophagus. A radiographic and manometric study on the evolution of megaoesophagus in dogs with developing axonal neuropathy

    International Nuclear Information System (INIS)

    Dogs given the neurotoxin acrylamide develop peripheral neuropathy and megaoesophagus. Sequential radiographic and manometric studies on the oesophagus demonstrated that the initial abnormalities consisted of a progressive decrease in the proportion of swallows that initiated peristalsis and a gradual increase in oesophageal calibre. Regurgitation, peristaltic failure and oesophageal dilatation all appeared within three days. The eating behaviour and gait abnormalities quickly resolved on stopping the neurotoxin, but the oesophagus remained dilated for longer. Previous studies have suggested that the abnormalities present in dogs which are developing a distal axonal neuropathy or in some dogs with idiopathic megaoesophagus may be limited to the proprioceptive elements of the oesophageal innervation. The present study suggests that the progressive inefficiency in the transmission of swallows and changes in oesophageal calibre in dogs with evolving megaoesophagus may be a consequence of damage to these proprioceptive elements

  18. Primary pericardial extragastrointestinal stromal tumor: A case report and literature review

    Science.gov (United States)

    ARPACI, TANER; TOKAT, FATMA; ARPACI, RABIA BOZDOGAN; AKBAS, TUGANA; UGURLUER, GAMZE; YAVUZ, SINAN

    2015-01-01

    Gastrointestinal stromal tumors (GISTs) are the most prevalent mesenchymal tumors of the gastrointestinal tract. GISTs are considered to originate from the interstitial cells of Cajal, the pacemakers of the peristaltic activity of the gastrointestinal tract. More than 95% of GISTs express KIT protein and discovered on GIST-1. GISTs may also be encountered in locations outside the gastrointestinal tract, in which case they are referred to as extra-GISTs (EGISTs) and often behave more aggressively. This is the case report of a primary pericardial EGIST in a 53-year-old male patient, confirmed by immunohistochemistry. To the best of our knowledge, this is the third case of EGIST diagnosed above the diaphragm, without being associated with the esophageal wall. Two cases of primary EGIST arising from the pleura were reported previously. In addition, this is the first reported case of an EGIST originating from the pericardium. PMID:26137136

  19. On the dynamic suction pumping of blood cells in tubular hearts

    CERN Document Server

    Battista, Nicholas A; Miller, Laura A

    2016-01-01

    Around the third week after gestation in embryonic development, the human heart consists only of a valvless tube, unlike a fully developed adult heart, which is multi-chambered. At this stage in development, the heart valves have not formed and so net flow of blood through the heart must be driven by a different mechanism. It is hypothesized that there are two possible mechanisms that drive blood flow at this stage - Liebau pumping (dynamic suction pumping or valveless pumping) and peristaltic pumping. We implement the immersed boundary method with adaptive mesh refinement (IBAMR) to numerically study the effect of hematocrit on the circulation around a valveless. Both peristalsis and dynamic suction pumping are considered. In the case of dynamic suction pumping, the heart and circulatory system is simplified as a flexible tube attached to a relatively rigid racetrack. For some Womersley number (Wo) regimes, there is significant net flow around the racetrack. We find that the addition of flexible blood cells ...

  20. Technical procedures for water resources: Volume 3, Environmental Field Program, Deaf Smith County Site, Texas: Final draft

    Energy Technology Data Exchange (ETDEWEB)

    1987-08-01

    To ensure that the environmental field program comprehensively addresses the issues and requirements of the project, a site study plan (SSP) has been prepared for Water Resources (ONWI, 1987). This technical procedure (TP) has been developed to implement the field program described in the Water Resources Site Study Plan. This procedure provides the general method for the field collection of water and sediment samples from playa lakes using an Alpha horizontal type sampler or equivalent or a peristaltic pump for water and a KB-coring devise or ponar grab for sediments. The samples will be preserved and then shipped to a laboratory for analysis. The water quality and sediment samples will be collected as part of the surface-water quality field study described in the Site Plan for Water Resources. 15 refs., 5 figs., 3 tabs.

  1. Solid Test Meal to Measure the Gastric Emptying with Magnetogastrography

    International Nuclear Information System (INIS)

    The gastric emptying is the time of evacuating the food ingested from the stomach to the duodenum in a controlled rate. Diverse studies express the results of the gastric emptying in form of half-time (t1/2). The Magnetogastrography (MGG) is a biomagnetic technique that has the advantage of not being invasive, radiation free and does not interfere with the privacy of the subject. The objective was to analyze the magnetic signal of magnetic tracers mixed in a solid food to measure gastric emptying using Magnetogastrography. The ingested test meal displayed a magnetic signal, which served to obtain the signal registered by the fluxgate and the peristaltic contractions could be calculated while the stomach was emptying. The solid food product developed results to work satisfactorily in magnetogastrography

  2. Optimal reservoir conditions for fluid extraction through permeable walls in the viscous limit

    CERN Document Server

    Herschlag, Gregory; Layton, Anita T

    2015-01-01

    In biological transport mechanisms such as insect respiration and renal filtration, fluid travels along a leaky channel allowing exchange with systems exterior the the channel. The channels in these systems may undergo peristaltic pumping which is thought to enhance the material exchange. To date, little analytic work has been done to study the effect of pumping on material extraction across the channel walls. In this paper, we examine a fluid extraction model in which fluid flowing through a leaky channel is exchanged with fluid in a reservoir. The channel walls are allowed to contract and expand uniformly, simulating a pumping mechanism. In order to efficiently determine solutions of the model, we derive a formal power series solution for the Stokes equations in a finite channel with uniformly contracting/expanding permeable walls. This flow has been well studied in the case of weakly permeable channel walls in which the normal velocity at the channel walls is proportional to the wall velocity. In contrast ...

  3. ANTIDIARRHOEL ACTIVITY OF METHANOLIC EXTRACT OF VERNONIA CINEREA (L. LESS ON FEMALE ALBINO RATS

    Directory of Open Access Journals (Sweden)

    Panday Ganesh

    2011-05-01

    Full Text Available The present study was conducted with the objectives of investigating antidiarrhoel activity of Vernonia cinerea whole plant (Family-Compositae, collected from tarai region of Uttarakhand. The plant extracts were obtained via cold extraction method. For the purpose of evaluating antidiarrhoel efficacy of methanolic extract of the plant, rats were used as test animal. The time of onset of first wet faeces increased significantly and dose dependently by the extract. It was excellent at higher doses (100 & 200 mg/kg body wt., orally. It indicated reduction in peristaltic movement of gastro intestinal tract of animals. The antidiarrhoel activity was further confirmed by its significant and dose dependent decrease in number of wet faeces and number of total faeces in comparison to rats used as control.

  4. Technical procedures for water resources: Volume 3, Environmental Field Program, Deaf Smith County Site, Texas: Final draft

    International Nuclear Information System (INIS)

    To ensure that the environmental field program comprehensively addresses the issues and requirements of the project, a site study plan (SSP) has been prepared for Water Resources (ONWI, 1987). This technical procedure (TP) has been developed to implement the field program described in the Water Resources Site Study Plan. This procedure provides the general method for the field collection of water and sediment samples from playa lakes using an Alpha horizontal type sampler or equivalent or a peristaltic pump for water and a KB-coring devise or ponar grab for sediments. The samples will be preserved and then shipped to a laboratory for analysis. The water quality and sediment samples will be collected as part of the surface-water quality field study described in the Site Plan for Water Resources. 15 refs., 5 figs., 3 tabs

  5. Modular microfluidic system as a model of cystic fibrosis airways

    DEFF Research Database (Denmark)

    Skolimowski, Maciej; Weiss Nielsen, Martin; Abeille, Fabien;

    2012-01-01

    A modular microfluidic airways model system that can simulate the changes in oxygen tension in different compartments of the cystic fibrosis (CF) airways was designed, developed, and tested. The fully reconfigurable system composed of modules with different functionalities: multichannel peristaltic...... pumps, bubble traps, gas exchange chip, and cell culture chambers. We have successfully applied this system for studying the antibiotic therapy of Pseudomonas aeruginosa, the bacteria mainly responsible for morbidity and mortality in cystic fibrosis, in different oxygen environments. Furthermore, we...... have mimicked the bacterial reinoculation of the aerobic compartments (lower respiratory tract) from the anaerobic compartments (cystic fibrosis sinuses) following an antibiotic treatment. This effect is hypothesised as the one on the main reasons for recurrent lung infections in cystic fibrosis...

  6. Drug: D01994 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available D01994 Drug Mosapride citrate hydrate (JP16); Mosapride citrate dihydrate; Gasmotin... (TN) C21H25ClFN3O3. C6H8O7. 2H2O 649.205 650.047 D01994.gif Peristaltic stimulant Same as: C13494 Therapeutic category: 2399 5-HT4-receptor agonist [HSA:3360] [K...ugs in Japan [BR:br08301] 2 Agents affecting individual organs 23 Digestive organ agents 239 Miscellaneous 2399 Others D01994... drugs [BR:br08310] G Protein-coupled receptors Rhodopsin family Serotonin 5-HT4-receptor [HSA:3360] [KO:K04160] Mosapride D01994... Mosapride citrate hydrate (JP16) CAS: 636582-62-2 PubChem: 7849056 LigandBox: D01994 A

  7. A fully resolved active musculo-mechanical model for esophageal transport

    CERN Document Server

    Kou, Wenjun; Griffith, Boyce E; Pandolfino, John E; Kahrilas, Peter J; Patankar, Neelesh A

    2015-01-01

    Esophageal transport is a physiological process that mechanically transports an ingested food bolus from the pharynx to the stomach via the esophagus, a multi-layered muscular tube. This process involves interactions between the bolus, the esophagus, and the neurally coordinated activation of the esophageal muscles. In this work, we use an immersed boundary (IB) approach to simulate peristaltic transport in the esophagus. The bolus is treated as a viscous fluid that is actively transported by the muscular esophagus, which is modeled as an actively contracting, fiber-reinforced tube. A simplified version of our model is verified by comparison to an analytic solution to the tube dilation problem. Three different complex models of the multi-layered esophagus, which differ in their activation patterns and the layouts of the mucosal layers, are then extensively tested. To our knowledge, these simulations are the first of their kind to incorporate the bolus, the multi-layered esophagus tube, and muscle activation i...

  8. Systolic Pressure in Different Percents of Stenosis at Major Arteries

    CERN Document Server

    Mirzaee, Mohammad Reza; Firoozabadi, Bahar; Dandaneband, Meitham

    2016-01-01

    - Modeling Human cardiovascular system is always an important issue. One of the most effective methods is using lumped model to reach to a complete model of human cardiovascular system. Such modeling with advanced considerations is used in this paper. Some of these considerations are as follow: Exact simulating of ventricles as pressure suppliers, peristaltic motion of descending arteries as additional suppliers, and dividing each vessel into more than one compartment to reach more accurate answers. Finally a circuit with more than 150 RLC segments and different elements is made. Then the verification of our complex circuit is done and at the end, obstruction as an important abnormality is investigated. For this aim different percents of obstruction in vital arteries are considered and the results are brought as different graphs at the end. According to physiological texts the citation of our simulation and its results are obvious. To earn productive information about arteries characteristics a 36-vessels mod...

  9. Hydrodynamics of undulatory fish schooling in lateral configurations

    CERN Document Server

    Zhang, Li Jeany

    2010-01-01

    The thrust benefits of lateral configurations of two-dimensional undulating fish-like bodies are investigated using high-fidelity numerical simulation. The solution of the Navier--Stokes equations is carried out with a viscous vortex particle method. Configurations of tethered pairs of fish arranged side by side are studied by varying the lateral separation distance and relative phase difference. It is shown that, in mirroring symmetry, the fish in the pair augment each other's thrust even at relatively large separations (up to ten body lengths). At small distances, this augmentation is primarily brought about by a peristaltic pumping in the gap between the fish, whereas at larger distances, the thrust is affected by subtle changes in the vortex shedding at the tail due to interactions with the other fish. In cases without symmetric undulation, one fish always draws more benefit from the interaction than the other. Finally, lateral configurations with three fish are studied with mirroring symmetry between nei...

  10. [Possible significance of prostaglandins in the pathogenesis of Crohn's disease].

    Science.gov (United States)

    Schmidt, E; Bruch, H P; Walter, K

    1977-04-01

    Prostaglandins (E1, E2, F2alpha) produce and intensify peristaltic contractions in the healthy human intestinal muscle system according to dosage (threshold I-10(-4) microng/ml--maximum effective concentration 1 microng/ml). By subsequent introduction of adrenaline, the intestinal muscle system activated by prostaglandines can be completely relaxed again. Intestinal muscles from patients with Crohn's disease show a marked deviation from this behaviour: 1. The intestinal muscle system is extremely sensitive to prostagladins: maximum concentrations are already reached by about a thousand times smaller concentration than in the intestines. 2. The dose of adrenaline does not lead to dialtion, which is usual, but to contraction of the muscle system. These changes in the contractility of the intestine can explain some components of the clinical symptomatology of Crohn's disease.

  11. A Continuous Flow System for the Measurement of Ambient Nitrogen Oxides [NO + NO2] Using Rhodamine B Hydrazide as a Chemosensor.

    Science.gov (United States)

    Malingappa, Pandurangappa; Yarradoddappa, Venkataramanappa

    2014-01-01

    A new chemosensor has been used to monitor atmospheric nitrogen oxides [NO + NO2] at parts per billion (ppb) level. It is based on the catalytic reaction of nitrogen oxides with rhodamine B hydrazide (RBH) to produce a colored compound through the hydrolysis of the amide bond of the molecule. A simple colorimeter has been used to monitor atmospheric nitrogen dioxide at ppb level. The air samples were purged through a sampling cuvette containing RBH solution using peristaltic pump. The proposed method has been successfully applied to monitor the ambient nitrogen dioxide levels at traffic junction points within the city limits and the results obtained are compared with the standard Griess-Ilosvay method. PMID:25210422

  12. Bridging Flows: Microfluidic End‐User Solutions

    DEFF Research Database (Denmark)

    Sabourin, David

    . A second practical challenge users face stems from the peripheral equipment, e.g. pumps, required to drive microfluidic devices. This equipment is often costly and bulky and results in limitations and restrictions on microfluidic device operation, such as the number of channels or devices which can...... be actuated or microscopic observation. To address the above issues interconnection and pumping solutions were developed. Methods for creating multiple, aligned, parallel and planar interconnections well suited to microscopy are described. Both reusable, non‐integrated, and permanent, integrated...... interconnection solutions are presented. The construction of twelve and eight channel miniaturized, mechanically actuated peristaltic pumps is also described. The small footprint of the pumps allows their placement adjacent to microfluidic devices and on microscope stages. The reusable, non...

  13. Characteristics of convective heat transfer in the MHD peristalsis of Carreau fluid with Joule heating

    Science.gov (United States)

    Hayat, T.; Farooq, S.; Ahmad, B.; Alsaedi, A.

    2016-04-01

    This article addresses the characteristics of convective heat transfer and radially imposed magnetic field on peristaltic flow of an incompressible Carreau fluid in a curved channel. Joule heating is also present. Mathematical analysis has been carried out under long wavelength and low Reynolds number considerations. Solutions of the resulting non-linear system for small values of Weissenberg number are constructed. The salient features of flow quantities are pointed out with particular focus to pumping, velocity, temperature and trapping. It is observed pressure gradient enhances for larger values of power law index parameter. The velocity and temperature are decreasing functions of radial magnetic field parameter. Further the impact of Weissenberg and Biot numbers on the temperature are opposite.

  14. Pathophysiological aspects of ureterorenoscopic management of upper urinary tract calculi

    DEFF Research Database (Denmark)

    Osther, Palle J S; Pedersen, Katja V; Lildal, Søren K;

    2016-01-01

    ureter and strain-induced ureteral contractions (peristalsis). Different receptor types modulate this peristaltic activity. β-receptor agonists have been investigated in animal and human trials for the purpose of relaxing the ureter. In randomized, placebo-controlled trials in pigs and humans, usage of...... ureterorenoscopy, potentially translating into harmful effects, and how such pathophysiological processes may be minimized. RECENT FINDINGS: Complications to ureterorenoscopy and postoperative pain seem to be related to intrarenal pressure and/or access. Mean intrarenal pressures in the range of 60-100 mmHg during...... ureterorenoscopy without access sheaths have been measured, thus by far exceeding the threshold for intrarenal backflow, potentially resulting in septic complications. Intrarenal pressure may be reduced by use of ureteral access sheaths, which, however, may cause ureteral damage due to the limited size of the...

  15. MHD pressure driven flow of nanofluid in curved channel

    Energy Technology Data Exchange (ETDEWEB)

    Noreen, S. [Department of Mathematics, COMSATS Institute of Information Technology, Park Road, Chak Shehzad, Islamabad 44000 (Pakistan); Qasim, M., E-mail: mq_qau@yahoo.com [Department of Mathematics, COMSATS Institute of Information Technology, Park Road, Chak Shehzad, Islamabad 44000 (Pakistan); Khan, Z.H. [Department of Mathematics, University of Malakand, Dir (Lower), Khyber Pakhtunkhwa (Pakistan)

    2015-11-01

    The pressure driven peristaltic flow of nanofluid in a curved channel is investigated. The flow exploration demeanors the induced magnetic field. Long wavelength and low Reynolds number approach is followed. Numerical solutions are obtained by employing shooting method. The effects of substantial parameters have been portrayed and discussed on the temperature and mass distributions, stream function, magnetic force function, induced magnetic field and pressure rise per wavelength. - Highlights: • Symmetry in the profiles of u, ϕ and h{sub x} is disturbed because of curvature effects. • The magnitude of longitudinal velocity increases with curvature. • The qualitative behavior of Nt and Nb on γ and Ω is opposite. • Magnitude h{sub x} decreases with k.

  16. Diamagnetically-stabilized levitation control of an intraluminal magnetic capsule.

    Science.gov (United States)

    Lam, Michael; Mintchev, Martin P

    2008-01-01

    Controlled navigation promotes full utilization of capsule endoscopy for reliable real-time diagnosis in the gastrointestinal (GI) tract, but intermittent natural peristalsis can disturb the navigational control, destabilize the capsule and take it out of levitation. A real-size magnetic navigation system that can handle peristaltic forces of up to 1.5 N was designed utilizing the computer-aided design (CAD) system Maxwell 3D (Ansoft, Pittsburg, PA), and was verified using a small-size physical experimental setup. The proposed system contains a pair of 50-cm in diameter, 10,000-turns copper electromagnets with a 10-cm by 10-cm ferrous core driven by currents of up to 300 Amperes and can successfully maintain position control over the levitating capsule during peristalsis. The addition of Bismuth diamagnetic casing for stabilizing the levitating capsule was also studied. PMID:19163990

  17. Power augmentation of cheap, sail-type, horizontal-axis wind-turbines

    Science.gov (United States)

    Fleming, P. D.; Probert, S. D.

    1982-09-01

    A history of the development of windpowered machinery is presented, and the installation of tipvanes and centerbodies to enhance the performance of low cost WECS for developing countries are examined experimentally. Particular attention is given to sail wing rotors equipped with tip fins, peristaltic pumps reparable by semiskilled labor, and various configurations of tip fins and center bodies, which deflect the wind outward from the hub to the sails. Cheap, flat-plate tip fins were found to effective in augmenting rotor performance by as much as 1.6 when facing only downwind. Best results were obtained with one tip vane per sail, with the fins downwind a distance at least equal to the pitch of a wind-filled sail. Further experimentation with stationary deflectors which redirect wind into the buckets of a Savonius rotor or the sails of a horizontal axis WECS are suggested.

  18. Comparison of totally tubeless percutaneous nephrolithotomy and standard percutaneous nephrolithotomy for kidney stones: a randomized, clinical trial.

    Science.gov (United States)

    Moosanejad, N; Firouzian, A; Hashemi, S A; Bahari, M; Fazli, M

    2016-01-01

    This study aimed to compare the totally tubeless percutaneous nephrolithotomy and standard percutaneous nephrolithotomy techniques regarding their rates of success and complications in patients with kidney stones. Patients were randomly assigned to two groups. Forty-four patients (24 men; mean age: 50.40±2.02 years) received totally tubeless percutaneous nephrolithotomy (PCNL; no nephrostomy catheter or ureteral catheter after PCNL) and 40 patients (18 men; mean age: 49.95 ± 13.38 years) underwent standard PCNL (a nephrostomy catheter and ureteral catheter were used after PCNL). All surgeries were performed by one surgeon. Postoperative changes in hemoglobin, the blood transfusion rate, changes in creatinine levels, operation time, analgesic need, hospitalization time, and complication rate were compared between the groups. No significant differences were observed in age, gender, stone size, and surgery side between the groups (Pnormal peristaltic ureter is the best drainage tube. PMID:27007650

  19. Phantom for comparing flow rates obtained with Doppler US and MR imaging

    International Nuclear Information System (INIS)

    When in vivo quantitative flow studies are performed with magnetic resonance (MR), imaging and Doppler ultrasound, a means for testing the accuracy of the measurement techniques is necessary. The authors have devised a nonferrous, tissue-mimicking phantom in which various sizes, configurations, and angles of tubing may be used. Removable ultrasonic tissue-mimicking material composed of graphite gel particles suspended in propanol and water allows tube pulsation simulating normal vasculature. With MR imaging, other materials such as water may be used. A reservoir of simulated blood and a high-speed peristaltic pump allows flow rates of up to 3.5 L/min. This newly designed phantom is easy to use and facilitates multimodality analysis of flow phenomena

  20. Standard test method for analysis of total and isotopic uranium and total thorium in soils by inductively coupled plasma-mass spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This test method covers the measurement of total uranium (U) and thorium (Th) concentrations in soils, as well as the determination of the isotopic weight percentages of 234U, 235U, 236U, and 238U, thereby allowing for the calculation of individual isotopic uranium activity or total uranium activity. This inductively coupled plasma-mass spectroscopy (ICP-MS) method is intended as an alternative analysis to methods such as alpha spectroscopy or thermal ionization mass spectroscopy (TIMS). Also, while this test method covers only those isotopes listed above, the instrumental technique may be expanded to cover other long-lived radioisotopes since the preparation technique includes the preconcentration of the actinide series of elements. The resultant sample volume can be further reduced for introduction into the ICP-MS via an electrothermal vaporization (ETV) unit or other sample introduction device, even though the standard peristaltic pump introduction is applied for this test method. The sample preparatio...