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Sample records for split cantilever beam

  1. Oscillations of end loaded cantilever beams

    International Nuclear Information System (INIS)

    Macho-Stadler, E; Elejalde-García, M J; Llanos-Vázquez, R

    2015-01-01

    This article presents several simple experiments based on changing transverse vibration frequencies in a cantilever beam, when acted on by an external attached mass load at the free end. By using a mechanical wave driver, available in introductory undergraduate laboratories, we provide various experimental results for end loaded cantilever beams that fit reasonably well into a linear equation. The behaviour of the cantilever beam’s weak-damping resonance response is studied for the case of metal resonance strips. As the mass load increases, a more pronounced decrease occurs in the fundamental frequency of beam vibration. It is important to note that cantilever construction is often used in architectural design and engineering construction projects but current analysis also predicts the influence of mass load on the sound generated by musical free reeds with boundary conditions similar to a cantilever beam. (paper)

  2. Forced Vibrations of a Cantilever Beam

    Science.gov (United States)

    Repetto, C. E.; Roatta, A.; Welti, R. J.

    2012-01-01

    The theoretical and experimental solutions for vibrations of a vertical-oriented, prismatic, thin cantilever beam are studied. The beam orientation is "downwards", i.e. the clamped end is above the free end, and it is subjected to a transverse movement at a selected frequency. Both the behaviour of the device driver and the beam's weak-damping…

  3. Microstructure cantilever beam for current measurement

    Directory of Open Access Journals (Sweden)

    M.T.E. Khan

    2010-01-01

    Full Text Available Most microelectromechanical systems (MEMS sensors are based on the microcantilever technology, which uses a broad range of design materials and structures. The benefit ofMEMStechnology is in developing devices with a lower cost, lower power consumption, higher performance and greater integration. A free-end cantilever beam with a magnetic material mass has been designed using MEMS software tools. The magnetic material was used to improve the sensitivity of the cantilever beam to an externally-applied magnetic field. The cantilever was designed to form a capacitance transducer, which consisted of variable capacitance where electrical and mechanical energies were exchanged. The aim of this paper was to analyse the system design of the microcantilever when subjected to a magnetic field produced by a current-carrying conductor. When the signal, a sinusoidal current with a constant frequency, was applied, the cantilever beam exhibited a vibration motion along the vertical axis when placed closer to the line current. This motion created corresponding capacitance changes and generated a voltage output proportional to the capacitive change in the signal-processing circuitry attached to the microcantilever. The equivalent massspring system theory was used to describe and analyse the effect of the natural frequency of the system vibrations and motion due to the applied magnetic field, in a single-degree of freedom. The main application of this microcantilever is in current measurements to develop a non-contact current sensor mote.

  4. Experimental investigation of fatigue in a cantilever energy harvesting beam

    Science.gov (United States)

    Avvari, Panduranga Vittal; Yang, Yaowen; Liu, Peiwen; Soh, Chee Kiong

    2015-03-01

    Over the last decade, cantilever energy harvesters gained immense popularity owing to the simplicity of the design and piezoelectric energy harvesting (PEH) using the cantilever design has undergone considerable evolution. The major drawback of a vibrating cantilever beam is its vulnerability to fatigue over a period of time. This article brings forth an experimental investigation into the phenomenon of fatigue of a PEH cantilever beam. As there has been very little literature reported in this area, an effort has been made to scrutinize the damage due to fatigue in a linear vibrating cantilever PEH beam consisting of an aluminum substrate with a piezoelectric macro-fiber composite (MFC) patch attached near the root of the beam and a tip mass attached to the beam. The beam was subjected to transverse vibrations and the behavior of the open circuit voltage was recorded with passing time. Moreover, electro-mechanical admittance readings were obtained periodically using the same MFC patch as a Structural health monitoring (SHM) sensor to assess the health of the PEH beam. The results show that with passing time the PEH beam underwent fatigue in both the substrate and MFC, which is observed in a complimentary trend in the voltage and admittance readings. The claim is further supported using the variation of root mean square deviation (RMSD) of the real part of admittance (conductance) readings. Thus, this study concludes that the fatigue issue should be addressed in the design of PEH for long term vibration energy harvesting.

  5. Non-conservative stability of spinning pretwisted cantilever beams

    Science.gov (United States)

    Karimi-Nobandegani, A.; Fazelzadeh, S. A.; Ghavanloo, E.

    2018-01-01

    The stability of a pretwisted cantilever beam spinning about its longitudinal axis and subjected to non-conservative force is investigated. In this study, it is assumed that the cantilever is embedded in viscoelastic medium, which is modeled by the Kelvin-Voigt foundation. Two different types of the non-conservative force are considered. The governing equations of motion and boundary conditions are derived by using Hamilton's principle. The finite element method is utilized to transform the coupled equations of motion to a general eigenvalue problem. The proposed model is justified by an excellent agreement between the present results and those reported in the literature. The effects of several design parameters including the pretwist angle, the cross section ratio, the viscoelastic parameters and load span length on the stability of the spinning pretwisted cantilevers are also examined. Moreover, the critical load and spinning speed and stability regions of the spinning cantilevers are identified. The results show that the design parameters significantly change the stability of the spinning pretwisted cantilever beams.

  6. Desain Cantilever Beam Piezoelectric Untuk Aplikasi Energi Harvesting

    Directory of Open Access Journals (Sweden)

    Roer Pawinanto

    2016-12-01

    Full Text Available Material piezoelektrik sudah mulai diaplkasikan dalam beberapa aplikasi seperti sebagai transduser untuk energi harvesting. Dalam studi ini kami menggunakan metode FEA untuk mengoptimasi beam piezoelektrik. Defleksi yang diperoleh pada studi ini yaitu sebesar 83 nm manakala frekuensi resonansi nya diperoleh di 13.4 Hz. Material piezoelektrik ini dapat menghasilkan defleksi yang besar ketika bergetar pada frekuensi resonansinya. Hasil optimisasi juga menunjukkan bahwa daya listrik yang dihasilkan mengindikasikan resistansi yang besar juga dan berkaitan dengan panjang material PZT serta dapat mempengaruhi defleksi dari cantilever beam.

  7. Dynamic modelling and experimental study of cantilever beam with clearance

    International Nuclear Information System (INIS)

    Li, B; Jin, W; Han, L; He, Z

    2012-01-01

    Clearances occur in almost all mechanical systems, typically such as the clearance between slide plate of gun barrel and guide. Therefore, to study the clearances of mechanisms can be very important to increase the working performance and lifetime of mechanisms. In this paper, rigid dynamic modelling of cantilever with clearance was done according to the subject investigated. In the rigid dynamic modelling, clearance is equivalent to the spring-dashpot model, the impact of beam and boundary face was also taken into consideration. In ADAMS software, the dynamic simulation was carried out according to the model above. The software simulated the movement of cantilever with clearance under external excitation. Research found: When the clearance is larger, the force of impact will become larger. In order to study how the stiffness of the cantilever's supporting part influences natural frequency of the system, A Euler beam which is restricted by a draught spring and a torsion spring at its end was raised. Through numerical calculation, the relationship between natural frequency and stiffness was found. When the value of the stiffness is close to the limit value, the corresponding boundary condition is illustrated. An ADAMS experiment was carried out to check the theory and the simulation.

  8. Position and mode dependent optical detection back-action in cantilever beam resonators

    DEFF Research Database (Denmark)

    Larsen, Tom; Schmid, Silvan; Dohn, Søren

    2017-01-01

    dependent optical back-action on cantilever beam resonators. A high power heating laser (100 μW) is scanned across a silicon nitride cantilever while its effect on the first three resonance modes is detected via a low-power readout laser (1 μW) positioned at the cantilever tip. We find that the measured...

  9. Cantilever-beam dynamic modulus for wood composite products. Part 1, apparatus

    Science.gov (United States)

    Chris Turk; John F. Hunt; David J. Marr

    2008-01-01

    A cantilever-beam vibration-testing apparatus has been developed to provide a means of dynamic and non-destructive evaluation of modulus of elasticity for small samples of wood or wood-composite material. The apparatus applies a known displacement to a cantilever beam and then releases the beam into its natural first-mode vibration and records displacement as a...

  10. Double Cantilever Beam Fracture Toughness Testing of Several Composite Materials

    Science.gov (United States)

    Kessler, Jeff A.; Adams, Donald F.

    1992-01-01

    Double-cantilever beam fracture toughness tests were performed by the Composite Materials Research Group on several different unidirectional composite materials provided by NASA Langley Research Center. The composite materials consisted of Hercules IM-7 carbon fiber and various matrix resin formulations. Multiple formulations of four different families of matrix resins were tested: LaRC - ITPI, LaRC - IA, RPT46T, and RP67/RP55. Report presents the materials tested and pertinent details supplied by NASA. For each material, three replicate specimens were tested. Multiple crack extensions were performed on each replicate.

  11. Automatic Optical Crack Tracking for Double Cantilever Beam Specimens

    Science.gov (United States)

    2015-01-01

    and Member, R.G., ‘‘Path Planning For Machine Vision Assisted, Teleoperated Pavement Crack Sealer,’’ Journal of Transportation Engineering 124:137...TECHN ICAL ART IC LE Automatic Optical Crack Tracking for Double Cantilever Beam Specimens B. Krull1,2, J. Patrick2,3, K. Hart2,4, S. White2,4, and N...accepted: January 31, 2015 doi:10.1111/ext.12148 Abstract An automatic crack tracking scheme is developed for measuring the tensile opening (mode I

  12. Mathematical analysis on a model for the rectangular cantilever beam

    International Nuclear Information System (INIS)

    Tsai, S.-H.; Kan, H.-C.

    2007-01-01

    The mechanical model for the rectangular cantilever beam proposed by Zhang et al is solved analytically by the series solution with mathematical properties investigated in detail. The derived series solution is proved convergent, and restrained only by the small deflection presumed by the Euler-Bernoulli beam theorem, and is applicable for calculating the deflection and curvature for any value of the exerted axial stress. The formulae estimating the accuracy of the coefficients and the series solution are developed from Stirling's approximation for the gamma function. The condition on the axial stress is developed, by which the genuinely nonlinear curvature can be approximated by a linear function and the deflection can be calculated from the boundary condition by a cubic polynomial. The additional redundant boundary condition used in Zhang's work is discussed, which should be removed since it fails to fit the model by inducing errors for calculating the deflection and the curvature. The present series solution approach provides formal deflection-stress and curvature-stress relations for the design of a MEMS micro-cantilever system as a bio-detection device. For self-assembly applications, the adsorbing material can be identified by solving the exerted axial stress from the series solution

  13. The stress intensity factor for the double cantilever beam

    Science.gov (United States)

    Fichter, W. B.

    1983-01-01

    Fourier transforms and the Wiener-Hopf technique are used in conjunction with plane elastostatics to examine the singular crack tip stress field in the double cantilever beam (DCB) specimen. In place of the Dirac delta function, a family of functions which duplicates the important features of the concentrated forces without introducing unmanageable mathematical complexities is used as a loading function. With terms of order h-squared/a-squared retained in the series expansion, the dimensionless stress intensity factor is found to be K (h to the 1/2)/P = 12 to the 1/2 (a/h + 0.6728 + 0.0377 h-squared/a-squared), in which P is the magnitude of the concentrated forces per unit thickness, a is the distance from the crack tip to the points of load application, and h is the height of each cantilever beam. The result is similar to that obtained by Gross and Srawley by fitting a line to discrete results from their boundary collocation analysis.

  14. Flutter of cantilevered interconnected beams with variable hinge positions

    Science.gov (United States)

    Deivasigamani, A.; McCarthy, J. M.; John, S.; Watkins, S.; Trivailo, P.; Coman, F.

    2013-04-01

    In this paper, flutter of slender, high-compliance cantilever beams in a fluid flow is discussed. Parametric factors that influence the critical flutter speed of these beams are examined theoretically, and experimentally validated. A relationship between the lowest bending-mode frequency of the beam and its critical flutter speed is established. A single ideal, revolute hinge with zero torsional stiffness is introduced at differing positions along the beam, so as to alter the effective natural frequency of the beam, and the effect of the hinge presence on the first few bending modes is analytically determined. A computational modal analysis is conducted in ANSYS® MechanicalTM and the results match well with analytical results, despite the difference in numerical schemes utilised between the two models. Experiments are then carried out in a smooth-flow wind tunnel to observe the critical flutter speed of these hinged beams. It is found that the critical flutter speed and oscillatory mode shape changes based on the hinge position. The experimental results are compared with the analytical and computational outcomes. Application of these connected bodies in the field of energy harvesting from fluid flow is discussed and the working principle of these harvesters is explained.

  15. Investigation of Subcombination Internal Resonances in Cantilever Beams

    Directory of Open Access Journals (Sweden)

    Haider N. Arafat

    1998-01-01

    Full Text Available Activation of subcombination internal resonances in transversely excited cantilever beams is investigated. The effect of geometric and inertia nonlinearities, which are cubic in the governing equation of motion, is considered. The method of time-averaged Lagrangian and virtual work is used to determine six nonlinear ordinary-differential equations governing the amplitudes and phases of the three interacting modes. Frequency- and force-response curves are generated for the case ω ≈ ω4 ≈ 1/2(ω2 + ω5. There are two possible responses: single-mode and three-mode responses. The single-mode periodic response is found to undergo supercritical and subcritical pitchfork bifurcations, which result in three-mode interactions. In the case of three-mode responses, there are conditions where the low-frequency mode dominates the response, resulting in high-amplitude quasiperiodic oscillations.

  16. Splitting of high power, cw proton beams

    Directory of Open Access Journals (Sweden)

    Alberto Facco

    2007-09-01

    Full Text Available A simple method for splitting a high power, continuous wave (cw proton beam in two or more branches with low losses has been developed in the framework of the EURISOL (European Isotope Separation On-Line Radioactive Ion Beam Facility design study. The aim of the system is to deliver up to 4 MW of H^{-} beam to the main radioactive ion beam production target, and up to 100 kW of proton beams to three more targets, simultaneously. A three-step method is used, which includes magnetic neutralization of a fraction of the main H^{-} beam, magnetic splitting of H^{-} and H^{0}, and stripping of H^{0} to H^{+}. The method allows slow raising and individual fine adjustment of the beam intensity in each branch.

  17. A Novel Approach to the Sensing of Liquid Density Using a Plastic Optical Fibre Cantilever Beam

    Science.gov (United States)

    Kulkarni, Atul; Kim, Youngjin; Kim, Taesung

    2009-01-01

    This article reports for the first time the use of a plastic optical fibre (POF) cantilever beam to measure the density of a liquid. The sensor is based on the Archimedes buoyancy principle. The sensor consists of a POF bonded on the surface of a metal beam in the form of a cantilever configuration, and at the free end of the beam a displacer is…

  18. Nonlinear Response of Cantilever Beams to Combination and Subcombination Resonances

    Directory of Open Access Journals (Sweden)

    Ali H. Nayfeh

    1998-01-01

    Full Text Available The nonlinear planar response of cantilever metallic beams to combination parametric and external subcombination resonances is investigated, taking into account the effects of cubic geometric and inertia nonlinearities. The beams considered here are assumed to have large length-to-width aspect ratios and thin rectangular cross sections. Hence, the effects of shear deformations and rotatory inertia are neglected. For the case of combination parametric resonance, a two-mode Galerkin discretization along with Hamilton’s extended principle is used to obtain two second-order nonlinear ordinary-differential equations of motion and associated boundary conditions. Then, the method of multiple scales is applied to obtain a set of four first-order nonlinear ordinary-differential equations governing the modulation of the amplitudes and phases of the two excited modes. For the case of subcombination resonance, the method of multiple scales is applied directly to the Lagrangian and virtual-work term. Then using Hamilton’s extended principle, we obtain a set of four first-order nonlinear ordinary-differential equations governing the amplitudes and phases of the two excited modes. In both cases, the modulation equations are used to generate frequency- and force-response curves. We found that the trivial solution exhibits a jump as it undergoes a subcritical pitchfork bifurcation. Similarly, the nontrivial solutions also exhibit jumps as they undergo saddle-node bifurcations.

  19. Integrated motion measurement illustrated by a cantilever beam

    Science.gov (United States)

    Örtel, T.; Wagner, J. F.; Saupe, F.

    2013-01-01

    The combination of inertial sensors and satellite navigation receivers like those of GPS (Global Positioning System) represents a very typical integrated navigation system. Integrated navigation is the most common example of integrated motion measurement determining the translational and angular position, velocity, and acceleration of a vehicle. Traditionally, this object is assumed to be a rigid body and the signals of its closely spaced sensors are referenced to a single point of the structure. During periods of low vehicle dynamics such common navigation systems typically show stability problems due to a loss of observability of some of the motion variables. The range of applications for integrated navigation systems can be expanded due to the continuously increasing performance of data processing and cheap sensors. Further, it can be shown that the stability of such a navigation system (i. e. of the motion observer employed for the system, typically a Kalman filter) can be sustained by distributing appropriately additional sensors over the vehicle structures at distinct locations. This comprises the compensation of drift effects of the system by adding sensors that are drift-free and the guarantee of the observability of all estimated motion components. Large structures like airplanes, space stations, skyscrapers, and tower cranes with distributed sensors, however, have to take the flexibility of the structure into account. This includes an appropriate kinematical model of the structure. In this case, the theory of integrated systems has to be expanded to flexible structures. On the other hand, the additional system information obtained can be used not only for vehicle guidance but also for structural control. Within this work individual kinematical models especially of a cantilever beam, idealizing e.g. the wing of an airplane, are developed and investigated with regard to the observability of the motion variables to guarantee a stable integrated system

  20. Atom beams split by gentle persuasion

    International Nuclear Information System (INIS)

    Pool, R.

    1994-01-01

    Two different research teams have taken a big step toward atom interferometry. They have succeeded in splitting atomic beams by using atoms in spin states that neither absorb nor reemit laser light. By proper adjustment of experimental conditions, atoms are changed from one spin state to another, without passing through the intermediary excited state. The atoms in essence absorb momentum from the laser photons, without absorption or emission of photons. The change in momentum deflects atoms in the proper spin state

  1. Micro-scale testing of ductile and brittle cantilever beam specimens in situ with a dual beam workstation

    International Nuclear Information System (INIS)

    Darnbrough, J E; Liu, D; Flewitt, P E J

    2013-01-01

    Micro-scale cantilever beam specimens created by focused ion beam milling have been mechanically loaded in situ at room temperature to observe the deformation and fracture of single crystal silicon, nanocrystalline nickel and thermal barrier coatings with a multilayer structure. The micro-scale preparation technique allows cantilever beams to be selected from preferred positions in the samples so that specific mechanical properties can be evaluated. As a consequence these microstructural specific properties can be combined with direct observation of the response of the test specimen throughout the period of the test. The measured mechanical properties and response for the materials given above are discussed and compared with previously published data. (paper)

  2. Cantilever Beam Static and Dynamic Response Comparison with Mid-Point Bending for Thin MDF composite Panels

    Science.gov (United States)

    John F. Hunt; Houjiang Zhang; Zhiren Guo; Feng Fu

    2013-01-01

    A new cantilever beam apparatus has been developed to measure static and vibrational properties of small and thin samples of wood or composite panels. The apparatus applies a known displacement to a cantilever beam, measures its static load, then releases it into its natural first mode of transverse vibration. Free vibrational tip displacements as a function of time...

  3. Determining shear modulus of thin wood composite materials using a cantilever beam vibration method

    Science.gov (United States)

    Cheng Guan; Houjiang Zhang; John F. Hunt; Haicheng Yan

    2016-01-01

    Shear modulus (G) of thin wood composite materials is one of several important indicators that characterizes mechanical properties. However, there is not an easy method to obtain this value. This study presents the use of a newly developed cantilever beam free vibration test apparatus to detect in-plane G of thin wood composite...

  4. Analysis of Cantilever-Beam Bending Stress Relaxation Properties of Thin Wood Composites

    Science.gov (United States)

    John F. Hunt; Houjiang Zhang; Yan Huang

    2015-01-01

    An equivalent strain method was used to analyze and determine material relaxation properties for specimens from particleboard, high density fiberboard, and medium density fiberboard. Cantilever beams were clamped and then deflected to 11 m and held for either 2 h or 3 h, while the load to maintain that deflection was measured vs. time. Plots of load relaxation for each...

  5. Higher Order Modes Excitation of Micro Cantilever Beams

    KAUST Repository

    Jaber, Nizar

    2014-05-01

    In this study, we present analytical and experimental investigation of electrically actuated micro cantilever based resonators. These devices are fabricated using polyimide and coated with chrome and gold layers from both sides. The cantilevers are highly curled up due to stress gradient, which is a common imperfection in surface micro machining. Using a laser Doppler vibrometer, we applied a noise signal to experimentally find the first four resonance frequencies. Then, using a data acquisition card, we swept the excitation frequency around the first four natural modes of vibrations. Theoretically, we derived a reduced order model using the Galerkin method to simulate the dynamics of the system. Extensive numerical analysis and computations were performed. The numerical analysis was able to provide good matching with experimental values of the resonance frequencies. Also, we proved the ability to excite higher order modes using partial electrodes with shapes that resemble the shape of the mode of interest. Such micro-resonators are shown to be promising for applications in mass and gas sensing.

  6. MEMS Capacitive Micro Thermometer Based on Tip Deflection of Bimetallic Cantilever Beam

    Directory of Open Access Journals (Sweden)

    Shahriar Kouravand

    2006-08-01

    Full Text Available Thermometry is an interested field in physics and metrology. A capacitive micro thermometer based on the tip deflection of bimetallic cantilever beam was designed and described in this paper. The governing thermo mechanical equations were derived and solved analytically. The temperature rising was expressed with respect to capacitance change of a comb drive. The results of beam deflection were compared well with the existing results.

  7. Determination of the J integral for laminated double cantilever beam specimens: The curvature approach

    DEFF Research Database (Denmark)

    Rask, Morten; Sørensen, Bent F.

    2012-01-01

    A new approach is proposed for measuring the J integral (and thus the fracture resistance) of interface cracks in multiply laminates. With this approach the J integral is found from beam curvatures and applied moments. Knowledge of ply layup and stiffness is not required. In order to test...... the accuracy of the proposed approach, double cantilever beam specimen loaded with uneven bending moments (DCB-UBM) specimens were tested and analysed using the curvature approach and a method based on laminate beam theory. Beam curvatures were determined using a configuration of strain gauges. Good agreement...

  8. Measurement of the Young’s modulus using micro-cantilevered beam actuated by electrostatic force

    Science.gov (United States)

    Wang, Zhichong; Zhang, Qichang; Wang, Chen

    2018-02-01

    Determining the Young’s modulus accurately is important in micro-electro-mechanical systems (MEMS) design. Generally, the Young’s modulus of a micro-component is measured by the resonance method, of which the actuation is electrostatic force. However, this method does not take the effect of the electrostatic force on the resonant frequency into consideration. Thus, the test error becomes more obvious as the DC voltage increases. In this paper, an improved resonance method, determining the Young’s modulus of a micro-cantilever beam, is proposed, which takes the nonlinearity of the electrostatic force into consideration. This method has three obvious advantages: only one simple micro-cantilevered beam sample is needed; it is unnecessary to find the initial thickness of the gas film between the beam and the substrate; the accuracy of the measurement result of the Young’s modulus is improved. In order to obtain the resonant frequency of a cantilevered beam actuated by a DC voltage, the dynamic equations of the micro-cantilevered beam in multi-field coupled situations are established, and the effect of the electrostatic force on the resonant frequency of the micro-beam is investigated. Results show that, the Young’s modulus can be found by measuring the resonant frequency and DC voltage. The dynamics performances of the micro-structure are influenced by the nonlinearity of the electrostatic force, and the electrostatic effect should be observed especially when the beam becomes smaller, through general studies. Finally, the experimental principle of measuring the Young’s modulus is designed and conducted to verify these theories. The Young’s modulus of brass is measured exactly.

  9. Note: Determination of torsional spring constant of atomic force microscopy cantilevers: Combining normal spring constant and classical beam theory

    DEFF Research Database (Denmark)

    Álvarez-Asencio, R.; Thormann, Esben; Rutland, M.W.

    2013-01-01

    A technique has been developed for the calculation of torsional spring constants for AFM cantilevers based on the combination of the normal spring constant and plate/beam theory. It is easy to apply and allow the determination of torsional constants for stiff cantilevers where the thermal power...

  10. A novel approach to the sensing of liquid density using a plastic optical fibre cantilever beam

    Science.gov (United States)

    Kulkarni, Atul; Kim, Youngjin; Kim, Taesung

    2009-01-01

    This article reports for the first time the use of a plastic optical fibre (POF) cantilever beam to measure the density of a liquid. The sensor is based on the Archimedes buoyancy principle. The sensor consists of a POF bonded on the surface of a metal beam in the form of a cantilever configuration, and at the free end of the beam a displacer is attached. Due to the apparent loss of the true weight of the displacer there is a deflection in the cantilever beam, which causes macro bending in the POF. The loss of intensity due to macro bending of the POF is a measure of the density of the liquid under test. The variation of weight loss with the density of different liquids showed that the weight loss is proportional to density. This sensor is capable of detecting the weight loss with respect to their densities even for liquids having close values of density like distilled water, tap water, and milk of various brands. The resolution of the sensor is observed to be 1.1 mg cm-3.

  11. Research on vibration measurement of a cantilever beam by twin-core fiber

    Science.gov (United States)

    Geng, Tao; Liu, Tao; Peng, Feng; Dai, Qiang; Yang, Yuan

    2009-05-01

    A novel interference transducer based on the measurement principle of multicore fiber interference for vibration measurement of a cantilever beam is designed in the paper. Twin-core fiber is special designed fiber, which contains a pair of parallel fiber core. Two paths integrated in one fiber not only greatly decreases sensor's volume, but also makes environment temperature effect approximately equal to each. A twin-core fiber which is pasted on the cantilever beam with epoxy resin is used as the sensing element. The twin-core fiber act as a two-beam in-fiber integrated interferometer that has a far-field interferometric fringe pattern which shift thereupon with the cantilever beam oscillates. CCD was used to measure the displacement of interferometer fringes instead of the traditional photodetector. The continuous capture of interference fringes was realized. The design of low pass filter and image smoothing were finished according to the characteristics of interference fringes. Orientation error of interference fringe center was removed. Displacement of fringe center was calculated and the spectrum of the displacement was analyzed with Fourier Transform. The system uses high-speed CCD camera as the photoelectric transformer. By using the high sensitivity twin-core fiber, the system realizes high precision measurement of vibration frequency, and ensures real-time performance. The experiment results show that the vibration measurement method is feasible and possesses potential application prospect in tiny vibration measure.

  12. MEMS Tunneling Micro Thermometer Based onTip Deflection of Bimetallic Cantilever Beam

    Directory of Open Access Journals (Sweden)

    Samrand K. Nezhadian

    2007-10-01

    Full Text Available Micro-electro-mechanical (MEM technology promises to significantly reduce the size, weight and cost of a variety of sensor systems. In this article has been described a highly sensitive novel type of thermometer based on deflection of a “bimetallic” microbeam. The proposed thermometer converts the thermal changes of a cantilevered bimetallic beam of submillimeter size into an electrical signal through tunneling-current modulation. The governing thermo-mechanical equation of a bimetallic cantilever beam has been derived and solved analytically. The obtained results show that the proposed tunneling micro thermometer is very sensitive to temperature changes due to exponential increasing of tunneling current but because of small gap between metallic electrodes, measurable range of temperature changes is small.

  13. 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.

  14. Vibration of a cantilever beam that slides axially in a rigid frictionless hole

    OpenAIRE

    DeVries, Mark R.

    1990-01-01

    Approved for public release; distribution unlimited. In 1979, Boresi and Salinas prepared a report that formulates the problem and proposes a solution procedure. The report was the result of an interest in the transient behavior of a gun barrel during recoil following firing. This research considers a cantilever beam which can move axially in and out of a rigid frictionless hole and is free to vibrate laterally outside the hole. Two Euler equations describing the lateral and axial motion o...

  15. Computation of Onset and Growth of Delamination in Double Cantilever beam Specimens Subjected to Fatigue Loading

    OpenAIRE

    Krishna Lok Singh; Madhu K.S; Mallikarjun Vaggar

    2014-01-01

    In this article, the delamination onset and growth behavior of double cantilever beam (DCB) specimens has been presented. The modeling of a debonded region using master and slave surface technique for DCB specimens is done in ABAQUS CAE. The analysis of DCB specimens comprising of fatigue cyclic load has been done in ABAQUS. An onset and Paris delamination growth regimes are plotted. The growth regime being linear in log-log scale, the prediction of constants of this regime has been obtained ...

  16. Nonlinear Vibrations of Cantilever Timoshenko Beams: A Homotopy Analysis

    Directory of Open Access Journals (Sweden)

    Shahram Shahlaei-Far

    Full Text Available Abstract This study analyzes the fourth-order nonlinear free vibration of a Timoshenko beam. We discretize the governing differential equation by Galerkin's procedure and then apply the homotopy analysis method (HAM to the obtained ordinary differential equation of the generalized coordinate. We derive novel analytical solutions for the nonlinear natural frequency and displacement to investigate the effects of rotary inertia, shear deformation, pre-tensile loads and slenderness ratios on the beam. In comparison to results achieved by perturbation techniques, this study demonstrates that a first-order approximation of HAM leads to highly accurate solutions, valid for a wide range of amplitude vibrations, of a high-order strongly nonlinear problem.

  17. Large deflection analysis of cantilever beam under end point and distributed load

    DEFF Research Database (Denmark)

    Kimiaeifar, Amin; Tolou, N; Barari, Amin

    2014-01-01

    distributed loads. Direct nonlinear solution by use of homotopy analysis method was implemented to drive the semi-exact solution of trajectory position of any point along the beam length. For the purpose of comparison, the deflections were calculated and compared to those of finite element method which...... requires numerical solution of simultaneous equations which is a significant drawback for optimization or reliability analysis. This paper is motivated to overcome these shortcomings by presenting an analytical solution for the large deflection analysis of a cantilever beam under free end point and uniform...

  18. Dynamic stability of a cantilevered Timoshenko beam on partial elastic foundations subjected to a follower force

    International Nuclear Information System (INIS)

    Ryu, Bong Jo; Shin, Kwang Bok; Yim, Kyung Bin; Yoon, Young Sik

    2006-01-01

    This paper presents the dynamic stability of a cantilevered Timoshenko beam with a concentrated mass, partially attached to elastic foundations, and subjected to a follower force. Governing equations are derived from the extended Hamilton's principle, and FEM is applied to solve the discretized equation. The influence of some parameters such as the elastic foundation parameter, the positions of partial elastic foundations, shear deformations, the rotary inertia of the beam, and the mass and the rotary inertia of the concentrated mass on the critical flutter load is investigated. Finally, the optimal attachment ratio of partial elastic foundation that maximizes the critical flutter load is presented

  19. Approximations for Large Deflection of a Cantilever Beam under a Terminal Follower Force and Nonlinear Pendulum

    Directory of Open Access Journals (Sweden)

    H. Vázquez-Leal

    2013-01-01

    Full Text Available In theoretical mechanics field, solution methods for nonlinear differential equations are very important because many problems are modelled using such equations. In particular, large deflection of a cantilever beam under a terminal follower force and nonlinear pendulum problem can be described by the same nonlinear differential equation. Therefore, in this work, we propose some approximate solutions for both problems using nonlinearities distribution homotopy perturbation method, homotopy perturbation method, and combinations with Laplace-Padé posttreatment. We will show the high accuracy of the proposed cantilever solutions, which are in good agreement with other reported solutions. Finally, for the pendulum case, the proposed approximation was useful to predict, accurately, the period for an angle up to 179.99999999∘ yielding a relative error of 0.01222747.

  20. Acoustic Split-Beam Echosounder Data (EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Southeast Fisheries Science Center Mississippi Laboratories collects data using Simrad EK60 scientific split-beam acoustic echosounders during resource...

  1. Delamination Analysis of a Multilayered Two-Dimensional Functionally Graded Cantilever Beam

    Science.gov (United States)

    Rizov, V.

    2017-11-01

    Delamination fracture behaviour of a multilayered two-dimensional functionally graded cantilever beam is analyzed in terms of the strain energy release rate. The beam is made of an arbitrary number of layers. Perfect adhesion is assumed between layers. Each layer has individual thickness and material properties. Besides, the material is two-dimensional functionally graded in the cross-section of each layer. There is a delamination crack located arbitrary between layers. The beam is loaded by a bending moment applied at the free end of the lower crack arm. The upper crack arm is free of stresses. The solution to strain energy release rate derived is applied to investigate the influence of the crack location and the material gradient on the delamination fracture. The results obtained can be used to optimize the multilayered two-dimensional functionally graded beam structure with respect to the delamination fracture behaviour.

  2. A new bi-axial cantilever beam design for biomechanics force measurements.

    Science.gov (United States)

    Lin, Huai-Ti; Trimmer, Barry A

    2012-08-31

    The demand for measuring forces exerted by animals during locomotion has increased dramatically as biomechanists strive to understand and implement biomechanical control strategies. In particular, multi-axial force transducers are often required to capture animal limb coordination patterns. Most existing force transducers employ strain gages arranged in a Wheatstone bridge on a cantilever beam. Bi-axial measurements require duplicating this arrangement in the transverse direction. In this paper, we reveal a method to embed a Wheatstone bridge inside another to allow bi-axial measurements without additional strain gages or additional second beams. This hybrid configuration resolves two force components from a single bridge circuit and simplifies fabrication for the simultaneous assessment of normal and transverse loads. This design can be implemented with two-dimensional fabrication techniques and can even be used to modify a common full bridge cantilever force transducer. As a demonstration of the new design, we built a simple beam which achieved bi-axial sensing capability that outperformed a conventional half-bridge-per-axis bi-axial strain gage design. We have used this design to measure the ground reaction forces of a crawling caterpillar and a caterpillar-mimicking soft robot. The simplicity and increased sensitivity of this method could facilitate bi-axial force measurements for experimental biologists. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Multi frequency excited MEMS cantilever beam resonator for Mixer-Filter applications

    KAUST Repository

    Chandran, Akhil A.

    2016-09-15

    Wireless communication uses Radio Frequency waves to transfer information from one point to another. The modern RF front end devices are implementing MEMS in their designs so as to exploit the inherent properties of MEMS devices, such as its low mass, low power consumption, and small size. Among the components in the RF transceivers, band pass filters and mixers play a vital role in achieving the optimum RF performance. And this paper aims at utilizing an electrostatically actuated micro cantilever beam resonator\\'s nonlinear frequency mixing property to realize a Mixer-Filter configuration through multi-frequency excitation. The paper studies about the statics and dynamics of the device. Simulations are carried out to study the added benefits of multi frequency excitation. The modelling of the cantilever beam has been done using a Reduced Order Model of the Euler-Bernoulli\\'s beam equation by implementing the Galerkin discretization. The device is shown to be able to down-convert signals from 960 MHz of frequency to an intermediate frequency around 50 MHz and 70 MHz in Phase 1 and 2, respectively. The simulation showed promising results to take the project to the next level. © 2016 IEEE.

  4. Analysis of the FELIX experiments with cantilevered beams and hollow cylinders

    International Nuclear Information System (INIS)

    Turner, L.R.; Hua, T.Q.; Lee, S.-Y.

    1986-01-01

    Experiments have been performed with the FELIX facility at Argonne National Laboratory to study the coupling between eddy currents and deflections and to provide data for validating eddy current computer programs. Experiments with cantilevered beams in crossed steady and decaying magnetic fields verify that coupling effects act to alleviate the large currents, deflections, and stresses predicted by uncoupled analyses. Measurements of magnetic fields induced in conducting hollow cylinders are analyzed by exponential fitting and by transfer functions. Spatial variation in the parameters of the exponential fit and in those of the one-and two-pole transfer functions suggests that several eddy current modes are acting in the cylinder test pieces. (author)

  5. Treatment of irreducible old atlantoaxial subluxation with cable-dragged reduction and cantilever beam internal fixation.

    Science.gov (United States)

    Liu, Xi; Liu, Hao; Li, Tao; Gong, Quan; Song, Yueming; Liu, Limin; Shi, Rui; Zhao, Xiaodan; Zhang, Wenli; Feng, Ganjun; Wang, Beiyu

    2011-07-01

    Retrospective case series study of surgical outcome for 21 atlantoaxial subluxation patients treated with a new technique, called cable-dragged reduction/cantilever beam internal fixation. Surgery was performed by a single surgeon. To describe and evaluate the cable-dragged reduction/cantilever beam internal fixation technique for the treatment for old atlantoaxial subluxation irreducible by traction. Management of old atlantoaxial subluxation has always been a difficult task. A more effective way to achieve surgical reduction is needed. Twenty one patients, aged 31.6 ± 13.3 years (range, 11-67 years), 17 men and four women, with atlantoaxial subluxation that failed to be reduced after 10 to 111 days in traction, underwent posterior cable-dragged reduction/cantilever beam internal fixation surgery. Frankel classification of neural function before surgery was the following: Frankel B, four patients; Frankel C, five patients; Frankel D, four patients; and Frankel E, eight patients. Plain radiographs, computed tomographic three-dimensional reconstructive images and magnetic resonance images of the cervical spine were obtained at 3, 6, and 12 months after surgery, and each year thereafter. No patient was lost to follow-up, and the follow-up time ranged from 6 months to 4 years. Rate of reduction and C1∼3 fusion, as well as improvement of neural function, were recorded and analyzed. The average follow-up period was 13.2 months. Radiographic evaluation of the group at follow-up showed 16 complete and five partial reductions, and satisfactory decompression and C1∼3 fusion in all cases. Neural function at the end of the follow-up was Frankel B still in one patient, Frankel C in seven patients, and Frankel E in 13 patients. Cable-dragged reduction/cantilever beam internal fixation is almost as effective for reduction as anterior release but is less invasive and risky. It has similar operative time and blood loss to occipitocervical fusion but avoids arthrodesis of

  6. Mimicking the cochlear amplifier in a cantilever beam using nonlinear velocity feedback control

    International Nuclear Information System (INIS)

    Joyce, Bryan S; Tarazaga, Pablo A

    2014-01-01

    The mammalian cochlea exhibits a nonlinear amplification which allows mammals to detect a large range of sound pressure levels while maintaining high frequency sensitivity. This work seeks to mimic the cochlea’s nonlinear amplification in a mechanical system. A nonlinear, velocity-based feedback control law is applied to a cantilever beam with piezoelectric actuators. The control law reduces the linear viscous damping of the system while introducing a cubic damping term. The result is a system which is positioned close to a Hopf bifurcation. Modelling and experimental results show that the beam with this control law undergoes a one-third amplitude scaling near the resonance frequency and an amplitude-dependent bandwidth. Both behaviors are characteristic of data obtained from the mammalian cochlea. This work could provide insight on the biological cochlea while producing bio-inspired sensors with a large dynamic range and sharp frequency sensitivity. (papers)

  7. Mimicking the cochlear amplifier in a cantilever beam using nonlinear velocity feedback control

    Science.gov (United States)

    Joyce, Bryan S.; Tarazaga, Pablo A.

    2014-07-01

    The mammalian cochlea exhibits a nonlinear amplification which allows mammals to detect a large range of sound pressure levels while maintaining high frequency sensitivity. This work seeks to mimic the cochlea’s nonlinear amplification in a mechanical system. A nonlinear, velocity-based feedback control law is applied to a cantilever beam with piezoelectric actuators. The control law reduces the linear viscous damping of the system while introducing a cubic damping term. The result is a system which is positioned close to a Hopf bifurcation. Modelling and experimental results show that the beam with this control law undergoes a one-third amplitude scaling near the resonance frequency and an amplitude-dependent bandwidth. Both behaviors are characteristic of data obtained from the mammalian cochlea. This work could provide insight on the biological cochlea while producing bio-inspired sensors with a large dynamic range and sharp frequency sensitivity.

  8. Frequency Shifts of Micro and Nano Cantilever Beam Resonators Due to Added Masses

    KAUST Repository

    Bouchaala, Adam M.

    2016-03-21

    We present analytical and numerical techniques to accurately calculate the shifts in the natural frequencies of electrically actuated micro and nano (carbon nanotubes (CNTs)) cantilever beams implemented as resonant sensors for mass detection of biological entities, particularly Escherichia coli (E. coli) and prostate specific antigen (PSA) cells. The beams are modeled as Euler-Bernoulli beams, including the nonlinear electrostatic forces and the added biological cells, which are modeled as discrete point masses. The frequency shifts due to the added masses of the cells are calculated for the fundamental and higher-order modes of vibrations. Analytical expressions of the natural frequency shifts under a direct current (DC) voltage and an added mass have been developed using perturbation techniques and the Galerkin approximation. Numerical techniques are also used to calculate the frequency shifts and compared with the analytical technique. We found that a hybrid approach that relies on the analytical perturbation expression and the Galerkin procedure for calculating accurately the static behavior presents the most computationally efficient approach. We found that using higher-order modes of vibration of micro-electro-mechanical-system (MEMS) beams or miniaturizing the sizes of the beams to nanoscale leads to significant improved frequency shifts, and thus increased sensitivities. © 2016 by ASME.

  9. Discussion of the Improved Methods for Analyzing a Cantilever Beam Carrying a Tip-Mass under Base Excitation

    Directory of Open Access Journals (Sweden)

    Wang Hongjin

    2014-01-01

    Full Text Available Two improved analytical methods of calculations for natural frequencies and mode shapes of a uniform cantilever beam carrying a tip-mass under base excitation are presented based on forced vibration theory and the method of separation of variables, respectively. The cantilever model is simplified in detail by replacing the tip-mass with an equivalent inertial force and inertial moment acting at the free end of the cantilever based on D’Alembert’s principle. The concentrated equivalent inertial force and inertial moment are further represented as distributed loads using Dirac Delta Function. In this case, some typical natural frequencies and mode shapes of the cantilever model are calculated by the improved and unimproved analytical methods. The comparing results show that, after improvement, these two methods are in extremely good agreement with each other even the offset distance between the gravity center of the tip-mass and the attachment point is large. As further verification, the transient and steady displacement responses of the cantilever system under a sine base excitation are presented in which two improved methods are separately utilized. Finally, an experimental cantilever system is fabricated and the theoretical displacement responses are validated by the experimental measurements successfully.

  10. Spin-valley splitting of electron beam in graphene

    Directory of Open Access Journals (Sweden)

    Yu Song

    2016-11-01

    Full Text Available We study spatial separation of the four degenerate spin-valley components of an electron beam in a EuO-induced and top-gated ferromagnetic/pristine/strained graphene structure. We show that, in a full resonant tunneling regime for all beam components, the formation of standing waves can lead sudden phase jumps ∼−π and giant lateral Goos-Hänchen shifts as large as the transverse beam width, while the interplay of the spin and valley imaginary wave vectors in the modulated regions can lead differences of resonant angles for the four spin-valley flavors, manifesting a spin-valley beam splitting effect. The splitting effect is found to be controllable by the gating and strain.

  11. Analyses of a cantilever-beam based instrument for evaluating the development of polymerization stresses.

    Science.gov (United States)

    Chiang, Martin Y M; Giuseppetti, Anthony A M; Qian, Jing; Dunkers, Joy P; Antonucci, Joseph M; Schumacher, Gary E; Gibson, Sheng-Lin

    2011-09-01

    This investigation was to generate (1) guidelines for designing a tensometer that satisfies the necessary accuracy and sensitivity requirements for measuring polymerization stress (PS), and (2) a formula for calculating PS. Polymerization stress remains one of the most critical properties of polymeric dental materials, yet methods that can accurately quantify PS have been limited in part due to the complexity of polymerization, and in part due to the instrumentation itself. In this study, we performed analytical and finite element analyses on a cantilever-beam based tensometer that is used to evaluate shrinkage stresses during the polymerization of dental restorative composites. The PS generated by a commercial dental composite determined using our new tensometer agrees with the predicted trend when the beam length and/or specimen height is varied. This work demonstrates the importance of beam dimension and component relative rigidity to the accuracy of PS evaluation. An analytical solution is also derived for the vertical beam deflection, which can be used for any combination of bending and shearing to properly calculate the PS. In addition, an easy-to-conduct calibration procedure is provided that is desirable for periodic tensometer recalibration. Published by Elsevier Ltd.

  12. Sizing Single Cantilever Beam Specimens for Characterizing Facesheet/Core Peel Debonding in Sandwich Structure

    Science.gov (United States)

    Ratcliffe, James G.

    2010-01-01

    This paper details part of an effort focused on the development of a standardized facesheet/core peel debonding test procedure. The purpose of the test is to characterize facesheet/core peel in sandwich structure, accomplished through the measurement of the critical strain energy release rate associated with the debonding process. The specific test method selected for the standardized test procedure utilizes a single cantilever beam (SCB) specimen configuration. The objective of the current work is to develop a method for establishing SCB specimen dimensions. This is achieved by imposing specific limitations on specimen dimensions, with the objectives of promoting a linear elastic specimen response, and simplifying the data reduction method required for computing the critical strain energy release rate associated with debonding. The sizing method is also designed to be suitable for incorporation into a standardized test protocol. Preliminary application of the resulting sizing method yields practical specimen dimensions.

  13. Broadband characteristics of vibration energy harvesting using one-dimensional phononic piezoelectric cantilever beams

    Energy Technology Data Exchange (ETDEWEB)

    Chen Zhongsheng, E-mail: czs_study@sina.com [Key Laboratory of Science and Technology on Integrated Logistics Support, College of Mechatronic Engineering and Automation, National University of Defense Technology, Changsha, Hunan 410073 (China); Yang Yongmin; Lu Zhimiao; Luo Yanting [Key Laboratory of Science and Technology on Integrated Logistics Support, College of Mechatronic Engineering and Automation, National University of Defense Technology, Changsha, Hunan 410073 (China)

    2013-02-01

    Nowadays broadband vibration energy harvesting using piezoelectric effect has become a research hotspot. The innovation in this paper is the widening of the resonant bandwidth of a piezoelectric harvester based on phononic band gaps, which is called one-dimensional phononic piezoelectric cantilever beams (PPCBs). Broadband characteristics of one-dimensional PPCBs are analyzed deeply and the vibration band gap can be calculated. The effects of different parameters on the vibration band gap are presented by both numerical and finite element simulations. Finally experimental tests are conducted to validate the proposed method. It can be concluded that it is feasible to use the PPCB for broadband vibration energy harvesting and there should be a compromise among related parameters for low-frequency vibrations.

  14. Double Cantilever Beam and End Notched Flexure Fracture Toughness Testing of Two Composite Materials

    Science.gov (United States)

    Kessler, Jeff A.; Adams, Donald F.

    1993-01-01

    Two different unidirectional composite materials were provided by NASA Langley Research Center and tested by the Composite Materials Research Group within the Department of Mechanical Engineering at the University of Wyoming. Double cantilever beam and end notched flexure tests were performed to measure the mode I (crack opening) and mode II (sliding or shear) interlaminar fracture toughness of the two materials. The two composites consisted of IM7 carbon fiber combined with either RP46 resin toughened with special formulation of LaRC IA resin, known as JJS1356; or PES chain extended thermoplastic resin known as JJS1361. Double Cantilever Beam Specimen Configuration and Test Methods As received from NASA, the test specimens were nominally 0.5 inch wide, 6 inches long, and 0.2 inch thick. A 1 inch long Kapton insert at the midplane of one end of the specimen (placed during laminate fabrication) facilitated crack initiation and extension. It was noted that the specimens provided were smaller than the nominal 1.5 inch wide, 9.0 inch long configuration specified. Similarly, the Kapton inserts were of greater length than those in the present specimens. Hence, the data below should not be compared directly to those generated with the referenced methods. No preconditioning was performed on the specimens prior to testing. In general, the methodology was used for the present work. Crack opening loads were introduced to the specimens via piano hinges attached to the main specimen faces at a single end of each specimen. Hinges were bolted to the specimens using the technique presented. The cracks were extended a small distance from the end of the Kapton insert prior to testing. Just before precracking, the sides of the specimens were coated with water-soluble typewriter correction fluid to aid in crack visualization. Scribe marks were then made in the coating at half-inch intervals.

  15. A Theoretical and Experimental Investigation on Free Vibration Vehavior of a Cantilever Beam with a Breathing Crack

    Directory of Open Access Journals (Sweden)

    M. Rezaee

    2012-01-01

    Full Text Available In this paper the free nonlinear vibration behavior of a cracked cantilever beam is investigated both theoretically and experimentally. For simplicity, the dynamic behavior of a cracked beam vibrating at its first mode is simulated using a simple single degree of freedom lumped parameter system. The time varying stiffness is modeled using a harmonic function. The governing equation of motion is solved by a perturbation method – the method of Multiple Scales.

  16. AN ELASTIC STRESS ANALYSIS FOR A POLYMER MATRIX COMPOSITE CANTILEVER BEAM SUBJECTED TO A SINGLE TRANSVERSE FORCE

    Directory of Open Access Journals (Sweden)

    Ayla TEKİN

    2004-03-01

    Full Text Available In this study, elasto-plastic stress analysis is carried out in a polymer matrix composite cantilever beam of arbitrary fiber orientation subjected to a single transverse force applied to the free end by using the anisotropic elasticity theory. The residual stress component of ?x and yield points are determined for 0°, 30°, 45°, 60° and 90° fiber orientation angles. The yielding begins for 0° and 90° fiber orientation angles at the upper and lower surfaces of the beam at the same distances from the free end. It is seen that the yielding begins for 30°, 45° and 60° fiber orientation angles at the upper surface of the beam. The intensity of the residual stress component of ?x is maximum at the upper and lower surfaces of the beam. In this study, the residual stress component of ?x obtained for the polymer matrix composite thermoplastic cantilever beam reinforced by reinforced unidirectional fibers is compared with that of the thermoplastic cantilever beam reinforced by woven Cr-Ni steel fibers.

  17. Load Identification for a Cantilever Beam Based on Fiber Bragg Grating Sensors

    Directory of Open Access Journals (Sweden)

    Xuegang Song

    2017-07-01

    Full Text Available Load identification plays an important role in structural health monitoring, which aims at preventing structural failures. In order to identify load for linear systems and nonlinear systems, this paper presents methods to identify load for a cantilever beam based on dynamic strain measurement by Fiber Bragg Grating (FBG sensors. For linear systems, the proposed inverse method consists of Kalman filter with no load terms and a linear estimator. For nonlinear systems, the proposed inverse method consists of cubature Kalman filter (CKF with no load terms and a nonlinear estimator. In the process of load identification, the state equations of the beam structures are constructed by using the finite element method (FEM. Kalman filter or CKF is used to suppress noise. The residual innovation sequences, gain matrix, and innovation covariance generated by Kalman filter or CKF are used to identify a load. To prove the effectiveness of the proposed method, numerical simulations and experiments of the beam structures are employed and the results show that the method has an excellent performance.

  18. Chemical sensor with oscillating cantilevered probe

    Science.gov (United States)

    Adams, Jesse D

    2013-02-05

    The invention provides a method of detecting a chemical species with an oscillating cantilevered probe. A cantilevered beam is driven into oscillation with a drive mechanism coupled to the cantilevered beam. A free end of the oscillating cantilevered beam is tapped against a mechanical stop coupled to a base end of the cantilevered beam. An amplitude of the oscillating cantilevered beam is measured with a sense mechanism coupled to the cantilevered beam. A treated portion of the cantilevered beam is exposed to the chemical species, wherein the cantilevered beam bends when exposed to the chemical species. A second amplitude of the oscillating cantilevered beam is measured, and the chemical species is determined based on the measured amplitudes.

  19. Adaptive Model Predictive Vibration Control of a Cantilever Beam with Real-Time Parameter Estimation

    Directory of Open Access Journals (Sweden)

    Gergely Takács

    2014-01-01

    Full Text Available This paper presents an adaptive-predictive vibration control system using extended Kalman filtering for the joint estimation of system states and model parameters. A fixed-free cantilever beam equipped with piezoceramic actuators serves as a test platform to validate the proposed control strategy. Deflection readings taken at the end of the beam have been used to reconstruct the position and velocity information for a second-order state-space model. In addition to the states, the dynamic system has been augmented by the unknown model parameters: stiffness, damping constant, and a voltage/force conversion constant, characterizing the actuating effect of the piezoceramic transducers. The states and parameters of this augmented system have been estimated in real time, using the hybrid extended Kalman filter. The estimated model parameters have been applied to define the continuous state-space model of the vibrating system, which in turn is discretized for the predictive controller. The model predictive control algorithm generates state predictions and dual-mode quadratic cost prediction matrices based on the updated discrete state-space models. The resulting cost function is then minimized using quadratic programming to find the sequence of optimal but constrained control inputs. The proposed active vibration control system is implemented and evaluated experimentally to investigate the viability of the control method.

  20. Vibration responses analysis of an elastic-support cantilever beam with crack and offset boundary

    Science.gov (United States)

    Zhang, Wensheng; Ma, Hui; Zeng, Jin; Wu, Shuang; Wen, Bangchun

    2017-10-01

    In this study, a finite element model of an elastic-support cantilever beam with crack and offset boundary is established by using mixed elements in ANSYS software. In the proposed model, different contact elements are adopted to describe the breathing effect of crack and offset boundary, and spring elements are used to simulate the elastic support, and the model is also validated by comparing the natural frequencies with those in published literatures. Based on the developed model, the combined effects of the crack and offset boundary on the system dynamic characteristics are studied. The results indicate that the amplitude of double frequency component (2fe) firstly decreases and then increases with the offset values when the crack position is on the opposite side of offset boundary. 2fe may disappear when the crack and the offset boundary locate at a certain position. In addition, the more distant the offset boundary is, the more intense the system nonlinearity becomes. The amplitude of 2fe increases with the offset values when the crack position is on the same side of offset boundary under a constant crack depth and location. Moreover, it also shows some complicated frequency components due to the gradually strengthened nonlinearity of the system with the increasing offset values, and the obvious distortion phenomenon in the phase plane portraits can be observed near the super-harmonic resonance region. This study can provide some basis for the diagnosis of beam-like structures with crack.

  1. Detection of Cracks in a Cantilever Beam Using Signal Processing and Strain Energy Based Model

    Science.gov (United States)

    Mehta, P.; Kureshi, A.; Lad, S.; Patel, N.; Sharma, D.

    2017-09-01

    Structure health monitoring is one of the most important aspects in an industry, as structures should work safely during their service life. Cracks are the most common damage that initiates a breakdown phase and hence timely and accurate detection of these cracks is imperative. In this article, a vibration based non-destructive technique is presented to detect one or multiple edge cracks in beam like structures. This model is based on variation in mode shapes and natural frequencies that provide accuracy in results as well as ease in practical applications. The crack location is identified using mode shapes of damaged beam wherein an appropriate signal processing technique is implemented by using which the noise in the signal can be reduced. Along with this, the crack severity is also determined using a strain energy based mathematical model. The model presented in this study is capable of detecting an arbitrary number of cracks in cantilever or simply supported configuration. The results obtained using the proposed method is also validated by considering few case studies.

  2. Experimental study of coupling between eddy currents and deflections in cantilevered beams as models of tokamak limiters

    International Nuclear Information System (INIS)

    Turner, L.R.; Hua, T.Q.

    1987-01-01

    The coupling between eddy current and motion in a cantilevered beam is examined. The beam, which provides a simple model for the limiter blades of a tokamak fusion reactor, was subjected to simultaneous orthogonal time-varying and constant magnetic fields. The dynamic deformation of the beam includes two different modes: a bending mode and a torsional mode. Interaction of current with each mode and with the combined modes of vibration is described. Experimental verification for the case without torsional motion was performed with the FELIX facility at ANL. The peak deflection and stresses are much less than those predicted without consideration given to the coupling. (Auth.)

  3. Experimental study of coupling between eddy currents and deflections in cantilevered beams as models of tokamak limiters

    International Nuclear Information System (INIS)

    Turner, L.R.; Hua, T.Q.

    1986-01-01

    The coupling between eddy current and motion in a cantilevered beam is examined. The beam, which provides a simple model for the limiter blades of a tokamak fusion reactor, was subjected to simultaneous orthogonal time-varying and constant magnetic fields. The dynamic deformation of the beam includes two different modes: a bending mode and a torsional mode. Interaction of current with each mode and with the combined modes of vibration in described. Experimental verification of the case without torsional motion was performed with the FELIX facility at ANL. The peak deflection and stresses are much less than those predicted without consideration given to the coupling

  4. Dosimetry study of split beam technique using megavoltage beams and its clinical implications. I

    International Nuclear Information System (INIS)

    Datta, R.; Mira, J.G.; Pomeroy, T.C.

    1979-01-01

    The problem of beam divergence and overlapping of adjacent fields in the treatment planning is well known. The use of split beam technique has been suggested as one way of addressing this problem. The present work reports a detailed dosimetry of this technique 60 Co beam (Theratron 780). The dose distributions at and near the junction plane between two adjacent fields were measured; they were compared with those for diverging fields (with and without gap on the skin). As an illustration, different treatment planning techniques for head and neck tumors and subsequent dose distributions are discussed. Our findings clearly indicate that the extension of penumbra near the geometrical edge of a split beam is considerably less than that of an open beam of the same field size. Consequently when two adjacent fields are used, the overdose at and near the junction plane is reduced greatly by the split beam. For head and neck tumors the split beam technique gives a much better dose distribution than any other conventional treatment techniques

  5. Electron Beam Welding of Gear Wheels by Splitted Beam

    Directory of Open Access Journals (Sweden)

    Dřímal Daniel

    2014-06-01

    Full Text Available This contribution deals with the issue of electron beam welding of high-accurate gear wheels composed of a spur gearing and fluted shaft joined with a face weld for automotive industry. Both parts made of the high-strength low-alloy steel are welded in the condition after final machining and heat treatment, performed by case hardening, whereas it is required that the run-out in the critical point of weldment after welding, i. e. after the final operation, would be 0.04 mm max..

  6. Nonlinear Phenomena in the Single-Mode Dynamics in an AFM Cantilever Beam

    KAUST Repository

    Ruzziconi, Laura

    2016-12-05

    This study deals with the nonlinear dynamics arising in an atomic force microscope cantilever beam. After analyzing the static behavior, a single degree of freedom Galerkin reduced order model is introduced, which describes the overall scenario of the structure response in a neighborhood of the primary resonance. Extensive numerical simulations are performed when both the forcing amplitude and frequency are varied, ranging from low up to elevated excitations. The coexistence of competing attractors with different characteristics is analyzed. Both the non-resonant and the resonant behavior are observed, as well as ranges of inevitable escape. Versatility of behavior is highlighted, which may be attractive in applications. Special attention is devoted to the effects of the tip-sample separation distance, since this aspect is of fundamental importance to understand the operation of an AFM. We explore the metamorphoses of the multistability region when the tip-sample separation distance is varied. To have a complete description of the AFM response, comprehensive behavior charts are introduced to detect the theoretical boundaries of appearance and disappearance of the main attractors. Also, extensive numerical simulations investigate the AFM response when both the forcing amplitude and the tip-sample separation distance are considered as control parameters. The main features are analyzed in detail and the obtained results are interpreted in terms of oscillations of the cantilever-tip ensemble. However, we note that all the aforementioned results represent the limit when disturbances are absent, which never occurs in practice. Here comes the importance of overcoming local investigations and exploring dynamics from a global perspective, by introducing dynamical integrity concepts. To extend the AFM results to the practical case where disturbances exist, we develop a dynamical integrity analysis. After performing a systematic basin of attraction analysis, integrity

  7. The actuation characterization of cantilevered unimorph beams with single crystal piezoelectric materials

    International Nuclear Information System (INIS)

    Bilgen, Onur; Friswell, Michael I; Amin Karami, M; Inman, Daniel J

    2011-01-01

    An experimental and theoretical electromechanical characterization of beam-like, uniform cross-section, unimorph structures employing single crystal piezoelectrics is presented. The purpose of the research is to understand and compare the actuation capabilities of several piezoelectric materials and substrate configurations so that optimal design choices can be employed in lightweight, low power aerodynamic applications. Monolithic devices made from three kinds of piezoelectrics—single crystal PMN–PZT (lead magnesium niobate–lead zirconate titanate) and the polycrystalline PZT-5A and PZT-5H types—are compared in a unimorph cantilevered beam configuration. A total of 24 unimorph specimens are fabricated and the validity of existing models is examined through experimentation. The tip velocity response to harmonic voltage excitation is measured and compared to the analytical prediction with the perfect bonding assumption. Summarizing, it was confirmed that the substrate-to-piezoelectric thickness ratio and substrate modulus are the important design parameters in determining the measured output of the unimorphs and the accuracy of the model prediction. The single crystal piezoelectrics demonstrated actuation authority two to four times higher (measured in terms of peak displacement per applied voltage) when compared to the polycrystalline piezoceramics for the same substrate material and geometry choice. In contrast to the higher actuation output, practical implementation issues are noted for the single crystal devices. The lack of grain boundaries (as in the polycrystalline material) makes the single crystals very 'brittle' and susceptible to stress concentrations. Another important limitation is the low transition temperature, which limits the use of conventional solder materials in creating electrical connections

  8. Identifying location and severity of multiple cracks in reinforced concrete cantilever beams using modal and wavelet analysis

    Directory of Open Access Journals (Sweden)

    Tahere Arefzade

    2016-06-01

    Full Text Available In this paper, a method of multiple cracks detection in a cantilever reinforced concrete beam based on wavelet transform is presented. For this purpose, different damage scenarios in concrete beam were considered. Then, the four first mode shapes of undamaged and damaged beam using ABAQUS software were extracted. The estimated mode shapes of the beam are analyzed by the continuous and discrete wavelet transform (CWT & DWT to detect the damage scenarios. It was found that DWT is more sensitive to damage location than CWT in the concrete beam which introduced in this paper. Also, the influence of the mode order and the effect of damage distance from support on the effectiveness of damage detection was evaluated. It was observed that the distance of cracks to each other have no effect on identifying their location.

  9. Acoustic beam splitting in a sonic crystal around a directional band gap

    International Nuclear Information System (INIS)

    Cicek Ahmet; Kaya Olgun Adem; Ulug Bulent

    2013-01-01

    Beam splitting upon refraction in a triangular sonic crystal composed of aluminum cylinders in air is experimentally and numerically demonstrated to occur due to finite source size, which facilitates circumvention of a directional band gap. Experiments reveal that two distinct beams emerge at crystal output, in agreement with the numerical results obtained through the finite-element method. Beam splitting occurs at sufficiently-small source sizes comparable to lattice periodicity determined by the spatial gap width in reciprocal space. Split beams propagate in equal amplitude, whereas beam splitting is destructed for oblique incidence above a critical incidence angle

  10. Interface debonding characterization by image correlation integrated with Double Cantilever Beam kinematics

    KAUST Repository

    Blaysat, Benoît

    2015-03-01

    A procedure is proposed for the identification of spatial interfacial traction profiles of peel loaded Double Cantilever Beam (DCB) samples, from which the corresponding traction-separation relation is extracted. The procedure draws upon recent developments in the area of non-contact optical techniques and makes use of so-called Integrated Digital Image Correlation (I-DIC) concepts. The distinctive feature of the I-DIC approach proposed herein is that the unknown degrees of freedom are not displacements or rotations, but the set of interfacial fracture properties describing the traction profile. A closed-form theoretical model is developed to reconstruct a mechanically admissible displacement field representing the deformation of the adhering layers during debonding in the DCB fracture test. The proposed modeling accounts for the spatial traction profile along the interface between the adherends using few degrees of freedom, i.e. crack tip position, maximum stress and size of the process zone. By minimizing the correlation residual with respect to the degrees of freedom, the full set of interfacial fracture properties is obtained through a one-step algorithm, revealing a substantial gain in terms of computational efficiency and robustness. It is shown that the identified traction profile can be effectively combined with the crack opening displacement to extract the corresponding traction-separation relation, i.e. the key input data for any cohesive zone model (CZM). The proposed procedure is validated by post-processing virtually deformed images generated through the finite element method. The robustness with respect to noisy data, as well as the low sensitivity to the initial guess, are demonstrated.

  11. Numerical Simulation of Output Response of PVDF Sensor Attached on a Cantilever Beam Subjected to Impact Loading

    Directory of Open Access Journals (Sweden)

    Cao Vu Dung

    2016-04-01

    Full Text Available Polyvinylidene Flouride (PVDF is a film-type polymer that has been used as sensors and actuators in various applications due to its mechanical toughness, flexibility, and low density. A PVDF sensor typically covers an area of the host structure over which mechanical stress/strain is averaged and converted to electrical energy. This study investigates the fundamental “stress-averaging” mechanism for dynamic strain sensing in the in-plane mode. A numerical simulation was conducted to simulate the “stress-averaging” mechanism of a PVDF sensor attached on a cantilever beam subjected to an impact loading, taking into account the contribution of piezoelectricity, the cantilever beam’s modal properties, and electronic signal conditioning. Impact tests and FEM analysis were also carried out to verify the numerical simulation results. The results of impact tests indicate the excellent capability of the attached PVDF sensor in capturing the fundamental natural frequencies of the cantilever beam. There is a good agreement between the PVDF sensor’s output voltage predicted by the numerical simulation and that obtained in the impact tests. Parametric studies were conducted to investigate the effects of sensor size and sensor position and it is shown that a larger sensor tends to generate higher output voltage than a smaller one at the same location. However, the effect of sensor location seems to be more significant for larger sensors due to the cancelling problem. Overall, PVDF sensors exhibit excellent sensing capability for in-plane dynamic strain induced by impact loading.

  12. Natural Frequency Testing and Model Correlation of Rocket Engine Structures in Liquid Hydrogen - Phase I, Cantilever Beam

    Science.gov (United States)

    Brown, Andrew M.; DeLessio, Jennifer L.; Jacobs, Preston W.

    2018-01-01

    Many structures in the launch vehicle industry operate in liquid hydrogen (LH2), from the hydrogen fuel tanks through the ducts and valves and into the pump sides of the turbopumps. Calculating the structural dynamic response of these structures is critical for successful qualification of this hardware, but accurate knowledge of the natural frequencies is based entirely on numerical or analytical predictions of frequency reduction due to the added-fluid-mass effect because testing in LH2 has always been considered too difficult and dangerous. This fluid effect is predicted to be approximately 4-5% using analytical formulations for simple cantilever beams. As part of a comprehensive test/analysis program to more accurately assess pump inducers operating in LH2, a series of frequency tests in LH2 were performed at NASA/Marshall Space Flight Center's unique cryogenic test facility. These frequency tests are coupled with modal tests in air and water to provide critical information not only on the mass effect of LH2, but also the cryogenic temperature effect on Young's Modulus for which the data is not extensive. The authors are unaware of any other reported natural frequency testing in this media. In addition to the inducer, a simple cantilever beam was also tested in the tank to provide a more easily modeled geometry as well as one that has an analytical solution for the mass effect. This data will prove critical for accurate structural dynamic analysis of these structures, which operate in a highly-dynamic environment.

  13. Pin cushion plasmonic device for polarization beam splitting, focusing, and beam position estimation.

    Science.gov (United States)

    Lerman, Gilad M; Levy, Uriel

    2013-03-13

    Great hopes rest on surface plasmon polaritons' (SPPs) potential to bring new functionalities and applications into various branches of optics. In this paper, we demonstrate a pin cushion structure capable of coupling light from free space into SPPs, split them based on the polarization content of the illuminating beam of light, and focus them into small spots. We also show that for a circularly or randomly polarized light, four focal spots will be generated at the center of each quarter circle comprising the pin cushion device. Furthermore, following the relation between the relative intensity of the obtained four focal spots and the relative position of the illuminating beam with respect to the structure, we propose and demonstrate the potential use of our structure as a miniaturized plasmonic version of the well-known four quadrant detector. Additional potential applications may vary from multichannel microscopy and multioptical traps to real time beam tracking systems.

  14. Magnetic properties of optimized cobalt nanospheres grown by focused electron beam induced deposition (FEBID on cantilever tips

    Directory of Open Access Journals (Sweden)

    Soraya Sangiao

    2017-10-01

    Full Text Available In this work, we present a detailed investigation of the magnetic properties of cobalt nanospheres grown on cantilever tips by focused electron beam induced deposition (FEBID. The cantilevers are extremely soft and the cobalt nanospheres are optimized for magnetic resonance force microscopy (MRFM experiments, which implies that the cobalt nanospheres must be as small as possible while bearing high saturation magnetization. It was found that the cobalt content and the corresponding saturation magnetization of the nanospheres decrease for nanosphere diameters less than 300 nm. Electron holography measurements show the formation of a magnetic vortex state in remanence, which nicely agrees with magnetic hysteresis loops performed by local magnetometry showing negligible remanent magnetization. As investigated by local magnetometry, optimal behavior for high-resolution MRFM has been found for cobalt nanospheres with a diameter of ≈200 nm, which present atomic cobalt content of ≈83 atom % and saturation magnetization of 106 A/m, around 70% of the bulk value. These results represent the first comprehensive investigation of the magnetic properties of cobalt nanospheres grown by FEBID for application in MRFM.

  15. Pressure sensor based on MEMS nano-cantilever beam structure as a heterodielectric gate electrode of dopingless TFET

    Science.gov (United States)

    Kumar, Gagan; Raman, Ashish

    2016-12-01

    Micro-electromechanical systems (MEMS) technology has enticed numerous scientists since recent decades particularly in the field of miniaturized-sensors and actuators. Pressure sensor is pivotal component in both of the forerunning fields. The pursuance of a pressure sensor is exigently relying upon its different physical properties i.e. Piezo-resistive, Piezoelectric, Capacitive, Magnetic and Electrostatic. This article presents an outline and scrutiny of the Doping-less Cantilever Based Pressure Sensor using tunnel field effect transistor technology. The propounded pressure sensor based on the principle of capacitive gate coupling, due to which the tunneling current is modified. Additionally, to enhance the affectability of pressure sensor, the work function of metal gate electrode is amended using gas molecule diffusion. Simulation uncovers a phenomenal relationship amongst hypothetical and practical accepts of configuration. The pressure sensor is composed at Silvaco Atlas tool utilizing 40 nm technologies. The performance results exhibit that the proposed model consumes ≤1 mW power and 250 μA tunneling current per nm bending of cantilever beam structure. The inclusive length of the proposed device is 100 nm.

  16. The splitted laser beam filamentation in interaction of laser and an exponential decay inhomogeneous underdense plasma

    International Nuclear Information System (INIS)

    Xia Xiongping; Yi Lin; Xu Bin; Lu Jianduo

    2011-01-01

    The splitted beam filamentation in interaction of laser and an exponential decay inhomogeneous underdense plasma is investigated. Based on Wentzel-Kramers-Brillouin (WKB) approximation and paraxial/nonparaxial ray theory, simulation results show that the steady beam width and single beam filamentation along the propagation distance in paraxial case is due to the influence of ponderomotive nonlinearity. In nonparaxial case, the influence of the off-axial of α 00 and α 02 (the departure of the beam from the Gaussian nature) and S 02 (the departure from the spherical nature) results in more complicated ponderomotive nonlinearity and changing of the channel density and refractive index, which led to the formation of two/three splitted beam filamentation and the self-distortion of beam width. In addition, influence of several parameters on two/three splitted beam filamentation is discussed.

  17. Shear and foundation effects on crack root rotation and mode-mixity in moment- and force-loaded single cantilever beam sandwich specimen

    DEFF Research Database (Denmark)

    Saseendran, Vishnu; Carlsson, Leif A.; Berggreen, Christian

    2017-01-01

    Foundation effects play a crucial role in sandwich fracture specimens with a soft core. Accurate estimation of deformationcharacteristics at the crack front is vital in understanding compliance, energy release rate and mode-mixity infracture test specimens. Beam on elastic foundation analysis...... beam specimen (in contrast to themoment-loaded case), it was found that the crack length normalized energy release rate and the mode-mixity phaseangle increase strongly as the crack length decreases, a result of increased dominance of shear loading....... of moment- and force-loaded single cantilever beam sandwichfracture specimens is presented here. In addition, finite element analysis of the single cantilever beam specimen isconducted to determine displacements, rotations, energy release rate and mode-mixity. Based on finite element analysis,a foundation...

  18. Natural Frequencies and Mode Shapes of a Nonlinear, Uniform Cantilevered Beam

    National Research Council Canada - National Science Library

    Marquez-Chisolm, Daniel J

    2006-01-01

    .... These experiments used a homogeneous 7075 aluminum beam and have been referenced as a baseline for the past thirty years to validate computer models and theories in an effort to build beams capable...

  19. Determining mode I cohesive law of Pinus pinaster by coupling double cantilever beam test with digital image correlation

    Directory of Open Access Journals (Sweden)

    J. Xavier

    2015-01-01

    Full Text Available The direct identification of the cohesive law in pure mode I of Pinus pinaster is addressed. The approach couples the double cantilever beam (DCB test with digital image correlation (DIC. Wooden beam specimens loaded in the radial-longitudinal (RL fracture propagation system are used. The strain energy release rate in mode I ( is uniquely determined from the load-displacement ( curve by means of the compliance-based beam method (CBBM. This method relies on the concept of equivalent elastic crack length ( and therefore does not require the monitoring of crack propagation during test. The crack tip opening displacement in mode I is determined from the displacement field at the initial crack tip. The cohesive law in mode I is then identified by numerical differentiation of the relationship. Moreover, the proposed procedure is validated by finite element analyses including cohesive zone modelling. It is concluded that the proposed data reduction scheme is adequate for assessing the cohesive law in pure mode I of P. pinaster

  20. Method and split cavity oscillator/modulator to generate pulsed particle beams and electromagnetic fields

    Science.gov (United States)

    Clark, M. Collins; Coleman, P. Dale; Marder, Barry M.

    1993-01-01

    A compact device called the split cavity modulator whose self-generated oscillating electromagnetic field converts a steady particle beam into a modulated particle beam. The particle beam experiences both signs of the oscillating electric field during the transit through the split cavity modulator. The modulated particle beam can then be used to generate microwaves at that frequency and through the use of extractors, high efficiency extraction of microwave power is enabled. The modulated beam and the microwave frequency can be varied by the placement of resistive wires at nodes of oscillation within the cavity. The short beam travel length through the cavity permit higher currents because both space charge and pinching limitations are reduced. The need for an applied magnetic field to control the beam has been eliminated.

  1. DETECTION OF DEFECTS IN A CANTILEVER BEAM USING MODAL TEST DATA

    Directory of Open Access Journals (Sweden)

    Ertuğrul ÇAM

    2004-03-01

    Full Text Available The aim of this study is to obtain information about the damage location and depth on the cracked beams. For this purpose, the vibrations due to impact shock are analyzed. The signal obtained from the defective and nondefective beams are compared both in time and frequency domain. By using these results, the location and depth of a defect can be determined from vibration signals.

  2. Physical mechanism of beam splitting based on reflective embedded double-layer grating

    Science.gov (United States)

    Wang, Bo; Li, Hongtao; Shu, Wenhao; Li, Wenhua; Chen, Li; Lei, Liang; Zhou, Jinyun

    2016-12-01

    It is not easy to achieve high performance for conventional beam splitters, such as high efficiency, good uniformity, polarization-independence, and wide bandwidth. A reflective embedded double-layer grating is described for beam splitting. With optimized grating profiles, the novel beam splitter can diffract both TE and TM polarizations into two orders with high performance. For the easy production, the fabrication tolerance is investigated and given. Most importantly, efficiencies more than 45% can be split into two orders within the wide bandwidth of 1412-1647 nm for TE polarization. The beam splitter based on multilayer coatings is sensitive to the incident angle and wavelength. And the bandwidth needs to be improved for the beam splitter based on simple grating. The design is of benefit for the performance improvement of the beam splitter by new grating configuration compared with the conventional simple grating.

  3. Beam splitting to improve target life in neutron generators

    International Nuclear Information System (INIS)

    Farrell, J.P.

    1976-01-01

    In a neutron generator in which a tritium-titanium target is bombarded by a deuterium ion beam, the target half-life is increased by separating the beam with a weak magnetic field to provide three separate beams of atomic, diatomic, and triatomic deuterium ions which all strike the target at different adjacent locations. Beam separation in this manner eliminates the problem of one type ion impairing the neutron generating efficiency of other type ions, thereby effecting more efficient utilization of the target material

  4. Cantilever sensors: Nanomechanical tools for diagnostics

    DEFF Research Database (Denmark)

    Datar, R.; Kim, S.; Jeon, S.

    2009-01-01

    and microfabrication technology for the label-free detection of biological molecules, allowing miniaturization. Molecular adsorption, when restricted to a single side of a deformable cantilever beam, results in measurable bending of the cantilever. This nanoscale deflection is caused by a variation in the cantilever...

  5. Laser Induced Breakdown Spectroscopy Based on Single Beam Splitting and Geometric Configuration for Effective Signal Enhancement

    OpenAIRE

    Yang, Guang; Lin, Qingyu; Ding, Yu; Tian, Di; Duan, Yixiang

    2015-01-01

    A new laser induced breakdown spectroscopy (LIBS) based on single-beam-splitting (SBS) and proper optical geometric configuration has been initially explored in this work for effective signal enhancement. In order to improve the interaction efficiency of laser energy with the ablated material, a laser beam operated in pulse mode was divided into two streams to ablate/excite the target sample in different directions instead of the conventional one beam excitation in single pulse LIBS (SP-LIBS)...

  6. Beam dynamics and wave packet splitting in a periodically curved optical waveguide: Multimode effects

    International Nuclear Information System (INIS)

    Marangoni, M.; Janner, D.; Ramponi, R.; Laporta, P.; Longhi, S.; Cianci, E.; Foglietti, V.

    2005-01-01

    A theoretical and experimental analysis of beam dynamics and wave packet splitting of light in a periodically bent optical waveguide, a phenomenon recently observed [Phys. Rev. Lett. 94, 073002 (2005)] which is the optical equivalent of adiabatic stabilization of atoms in intense and high-frequency laser fields, is presented in the multimode operational regime. Inhibition of wave packet splitting is theoretically predicted and experimentally observed for higher-order mode excitation

  7. Restoration of Natural Frequency of Cracked Cantilever Beam Using CNT Composite Patch: A Finite Element Study

    Directory of Open Access Journals (Sweden)

    Mahmoud Nadim Nahas

    2013-01-01

    Full Text Available Cyclic loadings cause fatigue to the elements of machines leading to crack initiation and propagation. This phenomenon decreases the age of the elements. In particular, cracks decrease the stiffness of the parts and lower the parts natural frequency, leading to failure under normal working conditions. This paper introduces a new application to carbon nanotube (CNT composites in the repairing process of a cracked specimen to restore the natural frequency of the specimen. Commonly, patches are made of high strength and high stiffness materials. This paper shows that even low stiffness materials, such as epoxy reinforced with CNT, can contribute to the repair of a cracked specimen. A 2D finite element (FE simulation is used to study the effects of bonding CNT composite patches over the crack location to repair cracked metal specimens. The effects of the patch thickness, length, and CNTs weight concentration ratio are investigated. Results showed an increase in the natural frequency of 31% compared to the cracked specimen at a crack depth of 70% of the beam depth and at a distance of 20% of the total beam length from the support.

  8. [Surgical treatment with cable dragged reduction and cantilever beam internal fixation by posterior approach for odontoid fracture associated with atlantoaxial dislocation].

    Science.gov (United States)

    Yang, Qi-Yua; Feng, Jing; Luo, Xiao-Li; Yang, Wen-Dong; Li, Ying-Bo; Fan, Bin; Feng, Zhi; Lai, Xian-Jin

    2016-10-25

    To explore the clinical effects of surgical treatment with cable dragged reduction and cantilever beam internal fixation by posterior approach for odontoid fracture associated with atlantoaxial dislocation. The clinical data of 12 patients with odontoid fracture associated with atlantoaxial dislocation from January 2008 to December 2013 were retrospectively analyzed. There were 8 males and 4 females, ranging in age from 21 to 53 years with an average of 37.2 years. Eleven cases were fresh fracture and 1 case was old fracture, all patients complicated with atlantoaxial anterior dislocation. According to Anderson-D' Alonzo typing method modified by Grauer, 3 cases were type IIA, 5 cases were type IIB, 3 cases were type IIC, and 1 case was type IIIA. All patients underwent surgical treatment with cable dragged reduction and cantilever beam internal fixation by posterior approach. JOA score and ADI method were respectively used to evaluate the nerve function and reductive condition of atlantoaxial dislocation. All patients were followed up from 6 months to 2 years with an average of 1 year and 3 months. At 1 week, 6 months after operation, and final follow up, JOA scores were 13.2±1.3, 13.5±1.4, 14.3±1.5, respectively, and these data were obviously better than that of preoperative 8.3±1.4( P dragged reduction and cantilever beam internal fixation by posterior approach for odontoid fracture associated with atlantoaxial dislocation is a good method, with advantage of firm fixation and high safety. It could obtain good clinical effects.

  9. Treatment of type II odontoid fracture with a novel technique: Titanium cable-dragged reduction and cantilever-beam internal fixation.

    Science.gov (United States)

    Zhu, Ce; Wang, Lei; Liu, Hao; Song, Yueming; Liu, Limin; Li, Tao; Gong, Quan

    2017-11-01

    Surgical methods for type II odontoid fracture can be classified into 2 main groups: anterior or posterior approach. A more effective way to achieve bone fusion with the lowest possible surgical risk is needed. Therefore, the aim of our study was to describe and evaluate a novel technique, cable-dragged reduction/cantilever beam internal fixation for the treatment of type II odontoid fracture.This was a retrospective study enrolled 34 patients underwent posterior cable-dragged reduction/cantilever-beam internal fixation surgery. Medical records, rates of reduction, the location of the instrumentation and fracture healing during follow-up were analyzed. Once fracture healing was obtained, instrumentation was removed. Neck pain (scored using a visual analog scale [VAS]), neck stiffness, patient satisfaction, and neck disability index (NDI) were recorded before and after removing the instrumentation during follow-up.The mean duration of follow up was 22.8 ± 5.3 months. There was no iatrogenic damage to nerves or blood vessels. Radiographic evaluation showed complete reduction in the 20 patients with fracture displacement and satisfactory fracture healing in all 34 cases. Titanium cable breakage was observed in 4 patients after fracture healing. After removal of instrumentation, significant improvements were seen in neck-pain VAS score, neck stiffness, patient satisfaction, and NDI (all P dragged reduction/cantilever-beam internal fixation was an optimal salvage maneuver to conventional surgical methods such as anterior screw fixation and C1-C2 screw-rod system. The operative difficulty and incidence of nerve and vascular injury were reduced. Its major disadvantage is the exposure and screw-setting at C3, which is left intact in traditional surgery, and it is suitable only for patients with intact C1 posterior arches.

  10. SEM in situ MiniCantilever Beam Bending of U-10Mo/Zr/Al Fuel Elements

    Energy Technology Data Exchange (ETDEWEB)

    Mook, William [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Baldwin, Jon K. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Martinez, Ricardo M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mara, Nathan A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-06-16

    In this work, the fracture behavior of Al/Zr and Zr/dU-10Mo interfaces was measured via the minicantilever bend technique. The energy dissipation rates were found to be approximately 3.7-5 mj/mm2 and 5.9 mj/mm2 for each interface, respectively. It was found that in order to test the Zr/U-10Mo interface, location of the hinge of the cantilever was a key parameter. While this test could be adapted to hot cell use through careful alignment fixturing and measurement of crack lengths with an optical microscope (as opposed to SEM, which was used here out of convenience), machining of the cantilevers via MiniMill in such a way as to locate the interfaces at the cantilever hinge, as well as proper placement of a femtosecond laser notch will continue to be key challenges in a hot cell environment.

  11. Tensile, Compression, Open-Hole Compression and Double Cantilever Beam Fracture Toughness Testing of Multiple NASA Langley Research Center Composite Materials

    Science.gov (United States)

    Adams, Donald F.

    1999-01-01

    The attached data summarizes the work performed by the Composite Materials Research Group at the University of Wyoming funded by the NASA LaRC Research Grant NAG-1-1294. The work consisted primarily of tension, compression, open-hole compression and double cantilever beam fracture toughness testing performed an a variety of NASA LaRC composite materials. Tests were performed at various environmental conditions and pre-conditioning requirements. The primary purpose of this work was to support the LaRC material development efforts. The data summaries are arranged in chronological order from oldest to newest.

  12. Amplification of Cooper pair splitting current in a graphene-based Cooper pair beam splitter geometry

    Science.gov (United States)

    Islam, SK Firoz; Saha, Arijit

    2017-09-01

    Motivated by the recent experiments [Scientific Reports 6, 23051 (2016), 10.1038/srep23051; Phys. Rev. Lett. 114, 096602 (2015), 10.1103/PhysRevLett.114.096602], we theoretically investigate Cooper pair splitting current in a graphene-based Cooper pair beam splitter geometry. By considering the graphene-based superconductor as an entangler device, instead of normal [two-dimensional (2D)] BCS superconductor, we show that the Cooper pair splitting current mediated by the crossed Andreev process is amplified compared to its normal superconductor counterpart. This amplification is attributed to the strong suppression of the local normal Andreev reflection process (arising from the Cooper pair splitting) from the graphene-based superconductor to lead via the same quantum dot, in comparison to the usual 2D superconductor. Due to the vanishing density of states at the Dirac point of undoped graphene, a doped graphene-based superconductor is considered here and it is observed that Cooper pair splitting current is very insensitive to the doping level in comparison to the usual 2D superconductor. The transport process of nonlocal spin-entangled electrons also depends on the type of pairing, i.e., whether the electron-hole pairing is onsite, intersublattice or the combination of both. The intersublattice pairing of graphene causes the maximum nonlocal Cooper pair splitting current, whereas the presence of both pairings reduces the Cooper pair splitting current.

  13. Broadband non-polarizing terahertz beam splitters with variable split ratio

    KAUST Repository

    Wei, Minggui

    2017-08-15

    Seeking effective terahertz functional devices has always aroused extensive attention. Of particular interest is the terahertz beam splitter. Here, we have proposed, designed, manufactured, and tested a broadband non-polarizing terahertz beam splitter with a variable split ratio based on an all-dielectric metasurface. The metasurface was created by patterning a dielectric surface of the N-step phase gradient and etching to a few hundred micrometers. The conversion efficiency as high as 81% under the normal incidence at 0.7 THz was achieved. Meanwhile, such a splitter works well over a broad frequency range. The split ratio of the proposed design can be continuously tuned by simply shifting the metasurface, and the angle of emergences can also be easily adjusted by choosing the step of phase gradients. The proposed design is non-polarizing, and its performance is kept under different polarizations.

  14. Laser induced breakdown spectroscopy based on single beam splitting and geometric configuration for effective signal enhancement.

    Science.gov (United States)

    Yang, Guang; Lin, Qingyu; Ding, Yu; Tian, Di; Duan, Yixiang

    2015-01-05

    A new laser induced breakdown spectroscopy (LIBS) based on single-beam-splitting (SBS) and proper optical geometric configuration has been initially explored in this work for effective signal enhancement. In order to improve the interaction efficiency of laser energy with the ablated material, a laser beam operated in pulse mode was divided into two streams to ablate/excite the target sample in different directions instead of the conventional one beam excitation in single pulse LIBS (SP-LIBS). In spatial configuration, the laser beam geometry plays an important role in the emission signal enhancement. Thus, an adjustable geometric configuration with variable incident angle between the two splitted laser beams was constructed for achieving maximum signal enhancement. With the optimized angles of 60° and 70° for Al and Cu atomic emission lines at 396.15 nm and 324.75 nm respectively, about 5.6- and 4.8-folds signal enhancements were achieved for aluminum alloy and copper alloy samples compared to SP-LIBS. Furthermore, the temporal analysis, in which the intensity of atomic lines in SP-LIBS decayed at least ten times faster than the SBS-LIBS, proved that the energy coupling efficiency of SBS-LIBS was significantly higher than that of SP-LIBS.

  15. Laser Induced Breakdown Spectroscopy Based on Single Beam Splitting and Geometric Configuration for Effective Signal Enhancement

    Science.gov (United States)

    Yang, Guang; Lin, Qingyu; Ding, Yu; Tian, Di; Duan, Yixiang

    2015-01-01

    A new laser induced breakdown spectroscopy (LIBS) based on single-beam-splitting (SBS) and proper optical geometric configuration has been initially explored in this work for effective signal enhancement. In order to improve the interaction efficiency of laser energy with the ablated material, a laser beam operated in pulse mode was divided into two streams to ablate/excite the target sample in different directions instead of the conventional one beam excitation in single pulse LIBS (SP-LIBS). In spatial configuration, the laser beam geometry plays an important role in the emission signal enhancement. Thus, an adjustable geometric configuration with variable incident angle between the two splitted laser beams was constructed for achieving maximum signal enhancement. With the optimized angles of 60° and 70° for Al and Cu atomic emission lines at 396.15 nm and 324.75 nm respectively, about 5.6- and 4.8-folds signal enhancements were achieved for aluminum alloy and copper alloy samples compared to SP-LIBS. Furthermore, the temporal analysis, in which the intensity of atomic lines in SP-LIBS decayed at least ten times faster than the SBS-LIBS, proved that the energy coupling efficiency of SBS-LIBS was significantly higher than that of SP-LIBS. PMID:25557721

  16. Experimentally validated structural vibration frequencies’ prediction from frictional temperature signatures using numerical simulation: A case of laced cantilever beam-like structures

    Directory of Open Access Journals (Sweden)

    Stephen M Talai

    2016-12-01

    Full Text Available This article pertains to the prediction of structural vibration frequencies from frictional temperature evolution through numerical simulation. To achieve this, a finite element analysis was carried on AISI 304 steel cantilever beam-like structures coupled with a lacing wire using the commercial software ABAQUS/CAE. The coupled temperature–displacement transient analysis simulated the frictional thermal generation. Furthermore, an experimental analysis was carried out with infrared cameras capturing the interfacial thermal images while the beams were subjected to forced excitation, thus validating the finite element analysis results. The analysed vibration frequencies using a MATLAB fast Fourier transform algorithm confirmed the validity of its prediction from the frictional temperature time domain waveform. This finding has a great significance to the mechanical and aerospace engineering communities for the effective structural health monitoring of dynamic structures online using infrared thermography, thus reducing the downtime and maintenance cost, leading to increased efficiency.

  17. Bandwidth Widening of Piezoelectric Cantilever Beam Arrays by Mass-Tip Tuning for Low-Frequency Vibration Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Eduard Dechant

    2017-12-01

    Full Text Available Wireless sensor networks usually rely on internal permanent or rechargeable batteries as a power supply, causing high maintenance efforts. An alternative solution is to supply the entire system by harvesting the ambient energy, for example, by transducing ambient vibrations into electric energy by virtue of the piezoelectric effect. The purpose of this paper is to present a simple engineering approach for the bandwidth optimization of vibration energy harvesting systems comprising multiple piezoelectric cantilevers (PECs. The frequency tuning of a particular cantilever is achieved by changing the tip mass. It is shown that the bandwidth enhancement by mass tuning is limited and requires several PECs with close resonance frequencies. At a fixed frequency detuning between subsequent PECs, the achievable bandwidth shows a saturation behavior as a function of the number of cantilevers used. Since the resonance frequency of each PEC is different, the output voltages at a particular excitation frequency have different amplitudes and phases. A simple power-transfer circuit where several PECs with an individual full wave bridge rectifier are connected in parallel allows one to extract the electrical power close to the theoretical maximum excluding the diode losses. The experiments performed on two- and three-PEC arrays show reasonable agreement with simulations and demonstrate that this power-transfer circuit additionally influences the frequency dependence of the harvested electrical power.

  18. High-precision laser microcutting and laser microdrilling using diffractive beam-splitting and high-precision flexible beam alignment

    Science.gov (United States)

    Zibner, F.; Fornaroli, C.; Holtkamp, J.; Shachaf, Lior; Kaplan, Natan; Gillner, A.

    2017-08-01

    High-precision laser micro machining gains more importance in industrial applications every month. Optical systems like the helical optics offer highest quality together with controllable and adjustable drilling geometry, thus as taper angle, aspect ratio and heat effected zone. The helical optics is based on a rotating Dove-prism which is mounted in a hollow shaft engine together with other optical elements like wedge prisms and plane plates. Although the achieved quality can be interpreted as extremely high the low process efficiency is a main reason that this manufacturing technology has only limited demand within the industrial market. The objective of the research studies presented in this paper is to dramatically increase process efficiency as well as process flexibility. During the last years, the average power of commercial ultra-short pulsed laser sources has increased significantly. The efficient utilization of the high average laser power in the field of material processing requires an effective distribution of the laser power onto the work piece. One approach to increase the efficiency is the application of beam splitting devices to enable parallel processing. Multi beam processing is used to parallelize the fabrication of periodic structures as most application only require a partial amount of the emitted ultra-short pulsed laser power. In order to achieve highest flexibility while using multi beam processing the single beams are diverted and re-guided in a way that enables the opportunity to process with each partial beam on locally apart probes or semimanufactures.

  19. Progresses in the studies of adiabatic splitting of charged particle beams by crossing nonlinear resonances

    Directory of Open Access Journals (Sweden)

    A. Franchi

    2009-01-01

    Full Text Available The multiturn extraction from a circular particle accelerator is performed by trapping the beam inside stable islands of the horizontal phase space. In general, by crossing a resonance of order n, n+1 beamlets are created whenever the resonance is stable, whereas if the resonance is unstable the beam is split in n parts. Islands are generated by nonlinear magnetic fields, whereas the trapping is realized by means of a given tune variation so to cross adiabatically a resonance. Experiments at the CERN Proton Synchrotron carried out in 2007 gave the evidence of protons trapped in stable islands while crossing the one-third and one-fifth resonances. Dedicated experiments were also carried out to study the trapping process and its reversibility properties. The results of these measurement campaigns are presented and discussed in this paper.

  20. Toward Higher-Order Mass Detection: Influence of an Adsorbate's Rotational Inertia and Eccentricity on the Resonant Response of a Bernoulli-Euler Cantilever Beam.

    Science.gov (United States)

    Heinrich, Stephen M; Dufour, Isabelle

    2015-11-19

    In this paper a new theoretical model is derived, the results of which permit a detailed examination of how the resonant characteristics of a cantilever are influenced by a particle (adsorbate) attached at an arbitrary position along the beam's length. Unlike most previous work, the particle need not be small in mass or dimension relative to the beam, and the adsorbate's geometric characteristics are incorporated into the model via its rotational inertia and eccentricity relative to the beam axis. For the special case in which the adsorbate's (translational) mass is indeed small, an analytical solution is obtained for the particle-induced resonant frequency shift of an arbitrary flexural mode, including the effects of rotational inertia and eccentricity. This solution is shown to possess the exact first-order behavior in the normalized particle mass and represents a generalization of analytical solutions derived by others in earlier studies. The results suggest the potential for "higher-order" nanobeam-based mass detection methods by which the multi-mode frequency response reflects not only the adsorbate's mass but also important geometric data related to its size, shape, or orientation (i.e., the mass distribution), thus resulting in more highly discriminatory techniques for discrete-mass sensing.

  1. Analysis of wood cantilever loaded at free end

    Science.gov (United States)

    Jen Y. Liu; Douglas R. Rammer

    2003-01-01

    A wood cantilever loaded at the free end was analyzed using the anisotropic elasticity theory. This report presents a two-dimensional numerical example of a Sitka spruce cantilever in the longitudinal-radial plane. When the grain slope is zero, ie., the beam axis coincides with the longitudinal axis of wood, the stresses in the beam and the deflection of the beam are...

  2. Diffraction inspired unidirectional and bidirectional beam splitting in defect-containing photonic structures without interface corrugations

    Energy Technology Data Exchange (ETDEWEB)

    Colak, Evrim [Electrical Engineering Department, Ankara University, Golbasi, 06830 Ankara (Turkey); Serebryannikov, Andriy E., E-mail: andser@amu.edu.pl [Faculty of Physics, Adam Mickiewicz University, 61-614 Poznań (Poland); Usik, P. V. [Institute of Radio Astronomy, National Academy of Sciences of Ukraine, 61002 Kharkiv (Ukraine); Ozbay, Ekmel [Nanotechnology Research Center—NANOTAM, Bilkent University, 06800 Ankara (Turkey)

    2016-05-21

    It is shown that strong diffractions and related dual-beam splitting can be obtained at transmission through the nonsymmetric structures that represent two slabs of photonic crystal (PhC) separated by a single coupled-cavity type defect layer, while there are no grating-like corrugations at the interfaces. The basic operation regimes include unidirectional and bidirectional splitting that occur due to the dominant contribution of the first positive and first negative diffraction orders to the transmission, which is typically connected with different manifestations of the asymmetric transmission phenomenon. Being the main component of the resulting transmission mechanism, diffractions appear owing to the effect exerted by the defect layer that works like an embedded diffractive element. Two mechanisms can co-exist in one structure, which differ, among others, in that whether dispersion allows coupling of zero order to a wave propagating in the regular, i.e., defect-free PhC segments or not. The possibility of strong diffractions and efficient splitting related to it strongly depend on the dispersion properties of the Floquet-Bloch modes of the PhC. Existence of one of the studied transmission scenarios is not affected by location of the defect layer.

  3. Statistical assessment of fish behavior from split-beam hydro-acoustic sampling

    International Nuclear Information System (INIS)

    McKinstry, Craig A.; Simmons, Mary Ann; Simmons, Carver S.; Johnson, Robert L.

    2005-01-01

    Statistical methods are presented for using echo-traces from split-beam hydro-acoustic sampling to assess fish behavior in response to a stimulus. The data presented are from a study designed to assess the response of free-ranging, lake-resident fish, primarily kokanee (Oncorhynchus nerka) and rainbow trout (Oncorhynchus mykiss) to high intensity strobe lights, and was conducted at Grand Coulee Dam on the Columbia River in Northern Washington State. The lights were deployed immediately upstream from the turbine intakes, in a region exposed to daily alternating periods of high and low flows. The study design included five down-looking split-beam transducers positioned in a line at incremental distances upstream from the strobe lights, and treatments applied in randomized pseudo-replicate blocks. Statistical methods included the use of odds-ratios from fitted loglinear models. Fish-track velocity vectors were modeled using circular probability distributions. Both analyses are depicted graphically. Study results suggest large increases of fish activity in the presence of the strobe lights, most notably at night and during periods of low flow. The lights also induced notable bimodality in the angular distributions of the fish track velocity vectors. Statistical/SUMmaries are presented along with interpretations on fish behavior

  4. Toward Higher-Order Mass Detection: Influence of an Adsorbate’s Rotational Inertia and Eccentricity on the Resonant Response of a Bernoulli-Euler Cantilever Beam

    Directory of Open Access Journals (Sweden)

    Stephen M. Heinrich

    2015-11-01

    Full Text Available In this paper a new theoretical model is derived, the results of which permit a detailed examination of how the resonant characteristics of a cantilever are influenced by a particle (adsorbate attached at an arbitrary position along the beam’s length. Unlike most previous work, the particle need not be small in mass or dimension relative to the beam, and the adsorbate’s geometric characteristics are incorporated into the model via its rotational inertia and eccentricity relative to the beam axis. For the special case in which the adsorbate’s (translational mass is indeed small, an analytical solution is obtained for the particle-induced resonant frequency shift of an arbitrary flexural mode, including the effects of rotational inertia and eccentricity. This solution is shown to possess the exact first-order behavior in the normalized particle mass and represents a generalization of analytical solutions derived by others in earlier studies. The results suggest the potential for “higher-order” nanobeam-based mass detection methods by which the multi-mode frequency response reflects not only the adsorbate’s mass but also important geometric data related to its size, shape, or orientation (i.e., the mass distribution, thus resulting in more highly discriminatory techniques for discrete-mass sensing.

  5. Toward Higher-Order Mass Detection: Influence of an Adsorbate’s Rotational Inertia and Eccentricity on the Resonant Response of a Bernoulli-Euler Cantilever Beam

    Science.gov (United States)

    Heinrich, Stephen M.; Dufour, Isabelle

    2015-01-01

    In this paper a new theoretical model is derived, the results of which permit a detailed examination of how the resonant characteristics of a cantilever are influenced by a particle (adsorbate) attached at an arbitrary position along the beam’s length. Unlike most previous work, the particle need not be small in mass or dimension relative to the beam, and the adsorbate’s geometric characteristics are incorporated into the model via its rotational inertia and eccentricity relative to the beam axis. For the special case in which the adsorbate’s (translational) mass is indeed small, an analytical solution is obtained for the particle-induced resonant frequency shift of an arbitrary flexural mode, including the effects of rotational inertia and eccentricity. This solution is shown to possess the exact first-order behavior in the normalized particle mass and represents a generalization of analytical solutions derived by others in earlier studies. The results suggest the potential for “higher-order” nanobeam-based mass detection methods by which the multi-mode frequency response reflects not only the adsorbate’s mass but also important geometric data related to its size, shape, or orientation (i.e., the mass distribution), thus resulting in more highly discriminatory techniques for discrete-mass sensing. PMID:26610493

  6. Structural single and multiple crack detection in cantilever beams using a hybrid Cuckoo-Nelder-Mead optimization method

    Science.gov (United States)

    Moezi, Seyed Alireza; Zakeri, Ehsan; Zare, Amin

    2018-01-01

    In this study, the number, location and depth of cracks created in several Euler-Bernoulli beams, such as a simple beam and a more complex multi-step beam are investigated. The location and depth of the created cracks are determined using the hybrid Cuckoo-Nelder-Mead Optimization Algorithm (COA-NM) with high accuracy. The natural frequencies of the cracked beams are determined by solving frequency response equations, and performing modal test experiments. Results of COA-NM show a higher accuracy and convergence speed compared with other methods such as GA-NM, PSO-NM, GA, PSO, COA and several previous studies. Amount of calculations performed by COA-NM to achieve this accuracy is much less compared to other methods.

  7. Real-time synchronous measurement of curing characteristics and polymerization stress in bone cements with a cantilever-beam based instrument

    Science.gov (United States)

    Palagummi, Sri Vikram; Landis, Forrest A.; Chiang, Martin Y. M.

    2018-03-01

    An instrumentation capable of simultaneously determining degree of conversion (DC), polymerization stress (PS), and polymerization exotherm (PE) in real time was introduced to self-curing bone cements. This comprises the combination of an in situ high-speed near-infrared spectrometer, a cantilever-beam instrument with compliance-variable feature, and a microprobe thermocouple. Two polymethylmethacrylate-based commercial bone cements, containing essentially the same raw materials but differ in their viscosity for orthopedic applications, were used to demonstrate the applicability of the instrumentation. The results show that for both the cements studied the final DC was marginally different, the final PS was different at the low compliance, the peak of the PE was similar, and their polymerization rates were significantly different. Systematic variation of instrumental compliance for testing reveals differences in the characteristics of PS profiles of both the cements. This emphasizes the importance of instrumental compliance in obtaining an accurate understanding of PS evaluation. Finally, the key advantage for the simultaneous measurements is that these polymerization properties can be correlated directly, thus providing higher measurement confidence and enables a more in-depth understanding of the network formation process.

  8. Investigation of the Effect of Material on Undamped Free Vibration of Cantilever Beams with Uniform Single Surface Crack

    Science.gov (United States)

    Mufazzal, Sameera; Muzakkir, S. M.; Zakir Jafri, Hasan

    2017-08-01

    Crack detection in structures is a critical area of research where the developments have been made out since decades. Various techniques are available for early identification and quantification of cracks to predict and prevent the unexpected sudden failure of structure and ensure uninterrupted service. Use of vibration analysis for detecting crack is one of the widely used techniques which offer lots of advantages over other like it is easier and less costly method and can be used for inaccessible components. The present work attempts to use modal analysis through FEA to investigate the effect of crack on natural frequency of vibration in beams of different materials, for three different crack location. From the result, it has been inferred that among Structural Steel (SS), Aluminium alloy (Al) and Gray Cast Iron (CI), the natural frequency is highest for Al beam and lowest for CI beam. Introduction of crack reduces the natural frequency of vibration, however, the effect of crack location on frequency is not uniform for different modes. Also, the trend is similar in beams of all the materials.

  9. On the calibration of rectangular atomic force microscope cantilevers modified by particle attachment and lamination

    International Nuclear Information System (INIS)

    Bowen, James; Zhang, Zhibing; Adams, Michael J; Cheneler, David; Ward, Michael C L; Walliman, Dominic; Arkless, Stuart G

    2010-01-01

    A simple but effective method for estimating the spring constant of commercially available atomic force microscope (AFM) cantilevers is presented, based on estimating the cantilever thickness from knowledge of its length, width, resonant frequency and the presence or absence of an added mass, such as a colloid probe at the cantilever apex, or a thin film of deposited material. The spring constant of the cantilever can then be estimated using standard equations for cantilever beams. The results are compared to spring constant calibration measurements performed using reference cantilevers. Additionally, the effect of the deposition of Cr and Ti thin films onto rectangular Si cantilevers is investigated

  10. Longwall mining “cutting cantilever beam theory” and 110 mining method in China—The third mining science innovation

    OpenAIRE

    Manchao He; Guolong Zhu; Zhibiao Guo

    2015-01-01

    With the third innovation in science and technology worldwide, China has also experienced this marvelous progress. Concerning the longwall mining in China, the “masonry beam theory” (MBT) was first proposed in the 1960s, illustrating that the transmission and equilibrium method of overburden pressure using reserved coal pillar in mined-out areas can be realized. This forms the so-called “121 mining method”, which lays a solid foundation for development of mining science and technology in Chin...

  11. Inferring the acoustic dead-zone volume by split-beam echo sounder with narrow-beam transducer on a noninertial platform.

    Science.gov (United States)

    Patel, Ruben; Pedersen, Geir; Ona, Egil

    2009-02-01

    Acoustic measurement of near-bottom fish with a directional transducer is generally problematical because the powerful bottom echo interferes with weaker echoes from fish within the main lobe but at greater ranges than that of the bottom. The volume that is obscured is called the dead zone. This has already been estimated for the special case of a flat horizontal bottom when observed by an echo sounder with a stable vertical transducer beam [Ona, E., and Mitson, R. B. (1996). ICES J. Mar. Sci. 53, 677-690]. The more general case of observation by a split-beam echo sounder with a transducer mounted on a noninertial platform is addressed here. This exploits the capability of a split-beam echo sounder to measure the bottom slope relative to the beam axis and thence to allow the dead-zone volume over a flat but sloping bottom to be estimated analytically. The method is established for the Simrad EK60 scientific echo sounder, with split-beam transducers operating at 18, 38, 70, 120, and 200 kHz. It is validated by comparing their estimates of seafloor slope near the Lofoten Islands, N67-70, with simultaneous measurements made by two hydrographic multibeam sonars, the Simrad EM100295 kHz and EM30030 kHz systems working in tandem.

  12. Angularly symmetric splitting of a light beam upon reflection and refraction at an air-dielectric plane boundary.

    Science.gov (United States)

    Azzam, R M A

    2015-12-01

    Conditions for achieving equal and opposite angular deflections of a light beam by reflection and refraction at an air-dielectric boundary are determined. Such angularly symmetric beam splitting (ASBS) is possible only if the angle of incidence is >60° by exactly one third of the angle of refraction. This simple law, plus Snell's law, leads to several analytical results that clarify all aspects of this phenomenon. In particular, it is shown that the intensities of the two symmetrically deflected beams can be equalized by proper choice of the prism refractive index and the azimuth of incident linearly polarized light. ASBS enables a geometrically attractive layout of optical systems that employ multiple prism beam splitters.

  13. Angularly symmetric splitting of a light beam upon reflection and refraction at an air-dielectric plane boundary: reply.

    Science.gov (United States)

    Azzam, R M A

    2016-05-01

    The simplified explicit expressions derived by Andersen [J. Opt. Soc. Am. A33, 984 (2016)JOAOD60740-323210.1364/JOSAA.32.000984], that relate to angularly symmetric beam splitting by reflection and refraction at an air-dielectric interface recently described by Azzam [J. Opt. Soc. Am. A32, 2436 (2015)JOAOD60740-323210.1364/JOSAA.32.002436], are welcome. A few additional remarks are also included in my reply to Andersen's comment.

  14. Parallel optical readout of cantilever arrays in dynamic mode

    NARCIS (Netherlands)

    Koelmans, W.W.; van Honschoten, J.W.; de Vries, Jeroen; Vettiger, P.; Abelmann, Leon; Elwenspoek, Michael Curt

    2010-01-01

    Parallel frequency readout of an array of cantilevers is demonstrated using optical beam deflection with a single laser–diode pair. Multi-frequency addressing makes the individual nanomechanical response of each cantilever distinguishable within the received signal. Addressing is accomplished by

  15. Cantilever piezoelectric energy harvester with multiple cavities

    International Nuclear Information System (INIS)

    S Srinivasulu Raju; M Umapathy; G Uma

    2015-01-01

    Energy harvesting employing piezoelectric materials in mechanical structures such as cantilever beams, plates, diaphragms, etc, has been an emerging area of research in recent years. The research in this area is also focused on structural tailoring to improve the harvested power from the energy harvesters. Towards this aim, this paper presents a method for improving the harvested power from a cantilever piezoelectric energy harvester by introducing multiple rectangular cavities. A generalized model for a piezoelectric energy harvester with multiple rectangular cavities at a single section and two sections is developed. A method is suggested to optimize the thickness of the cavities and the number of cavities required to generate a higher output voltage for a given cantilever beam structure. The performance of the optimized energy harvesters is evaluated analytically and through experimentation. The simulation and experimental results show that the performance of the energy harvester can be increased with multiple cavities compared to the harvester with a single cavity. (paper)

  16. Cantilever Based Mass Sensing

    DEFF Research Database (Denmark)

    Dohn, Søren

    2007-01-01

    suitable for a portable device and to investigate the possibility of enhancing the functionality and sensitivity of cantilever based mass sensors. A readout method based on the hard contact between the cantilever and a biased electrode placed in close proximity to the cantilever is proposed. The viability...... the mass and position of a particle attached to a cantilever to the resonant frequency. It is shown theoretical possible to find the mass and position of a particle by measurements of the resonant frequency of several bending modes. In the measurements the sensitivity of the cantilever based mass sensor...... is improved when operated at higher bending modes. By measuring the resonant frequency of several bending modes both the mass and position of an attached gold bead are determined....

  17. Comprehensive proton dose algorithm using pencil beam redefinition and recursive dynamic splitting

    OpenAIRE

    Gottschalk, Bernard

    2016-01-01

    We compute, from first principles, the absolute dose or fluence distribution per incident proton charge in a known heterogeneous terrain exposed to known proton beams. The algorithm is equally amenable to scattered or scanned beams. All objects in the terrain (including collimators) are sliced into slabs, of any convenient thickness, perpendicular to the nominal beam direction. Transport is by standard Fermi-Eyges theory. Transverse heterogeneities are handled by breaking up pencil beams (PBs...

  18. Transverse beam splitting made operational: Recent progress of the multi-turn extraction at the CERN proton synchrotron

    CERN Document Server

    AUTHOR|(CDS)2082016; Borburgh, Jan; Damjanovic, Sanja; Gilardoni, Simone; Giovannozzi, Massimo; Hourican, Michael; Kahle, Karsten; Michels, Olivier; Sterbini, Guido; Hernalsteens, Cedric; Le Godec, Gilles

    2016-01-01

    Following a successful commissioning period, the Multi-Turn Extraction (MTE) at the CERN Proton Synchrotron (PS) has been applied for the fixed-target physics programme at the Super Proton Synchrotron (SPS) since September 2015. This exceptional extraction technique was proposed to replace the long-serving Continuous Transfer (CT) extraction, which has the drawback of inducing high activation in the ring. MTE exploits the principles of non-linear beam dynamics to perform loss-free beam splitting in the horizontal phase space. Over multiple turns, the resulting beamlets are then transferred to the downstream accelerator. The operational deployment of MTE was rendered possible by the full understanding and mitigation of different hardware limitations and by redesigning the extraction trajectories and non-linear optics, which was required due to the installation of a dummy septum to reduce the activation of the magnetic extraction septum. The results of the related experimental and simulation studies, a summary ...

  19. Torsion and transverse bending of cantilever plates

    Science.gov (United States)

    Reissner, Eric; Stein, Manuel

    1951-01-01

    The problem of combined bending and torsion of cantilever plates of variable thickness, such as might be considered for solid thin high-speed airplane or missile wings, is considered in this paper. The deflections of the plate are assumed to vary linearly across the chord; minimization of the potential energy by means of the calculus of variations then leads to two ordinary linear differential equations for the bending deflections and the twist of the plate. Because the cantilever is analyzed as a plate rather than as a beam, the effect of constraint against axial warping in torsion is inherently included. The application of this method to specific problems involving static deflection, vibration, and buckling of cantilever plates is presented. In the static-deflection problems, taper and sweep are considered.

  20. A review of the concentrated photovoltaic/thermal (CPVT) hybrid solar systems based on the spectral beam splitting technology

    International Nuclear Information System (INIS)

    Ju, Xing; Xu, Chao; Han, Xue; Du, Xiaoze; Wei, Gaosheng; Yang, Yongping

    2017-01-01

    Highlights: • A review on spectral beam splitting (SBS) CPVT technologies is presented. • SBS methods including interference, liquid absorptive and other filters are discussed. • The researches of SBS CPVTs are reviewed comprehensively and summarized. • Recent research status and system performance characteristics are analysed. • Suggestions on the development of SBS CPVT technologies are proposed. - Abstract: This article presents a review on the research and development of spectral beam splitting concentrated photovoltaic/thermal (SBS CPVT) hybrid solar systems. The investigations on the SBS CPVT hybrid technologies had begun in the 1980s and were aimed at complete utilization of the solar irradiation over the whole solar spectrum using both PV cells and thermal absorbers. Several different SBS approaches were employed to achieve better conversion efficiencies, including the interference filter, liquid absorptive filter, holographic filter, luminescent filter, diffractive filter, combined interference and liquid absorptive filter, combined liquid and solid absorptive filter, and photovoltaics itself as a solid absorptive filter. The SBS CPVT systems were proposed or assembled in various system configurations for numerous purposes, such as domestic hot water, thermochemical reaction, hydrogen production, or even power generation. These researches and developments are comprehensively reviewed in this article, and the advantages and disadvantages of different SBS methods are presented and concluded. This paper also aims to provide a global point of view on research trends, market potential, technical obstacles, and the future work required for the development of SBS CPVT technology.

  1. Multipulse addressing of a Raman quantum memory: configurable beam splitting and efficient readout.

    Science.gov (United States)

    Reim, K F; Nunn, J; Jin, X-M; Michelberger, P S; Champion, T F M; England, D G; Lee, K C; Kolthammer, W S; Langford, N K; Walmsley, I A

    2012-06-29

    Quantum memories are vital to the scalability of photonic quantum information processing (PQIP), since the storage of photons enables repeat-until-success strategies. On the other hand, the key element of all PQIP architectures is the beam splitter, which allows us to coherently couple optical modes. Here, we show how to combine these crucial functionalities by addressing a Raman quantum memory with multiple control pulses. The result is a coherent optical storage device with an extremely large time bandwidth product, that functions as an array of dynamically configurable beam splitters, and that can be read out with arbitrarily high efficiency. Networks of such devices would allow fully scalable PQIP, with applications in quantum computation, long distance quantum communications and quantum metrology.

  2. Diagnostic Accuracy of Split-Bolus Single-Phase Contrast-Enhanced Cone-Beam CT for the Detection of Liver Tumors before Transarterial Chemoembolization.

    Science.gov (United States)

    Jonczyk, Martin; Chapiro, Julius; Collettini, Federico; Geisel, Dominik; Schnapauff, Dirk; Streitparth, Florian; Schmidt, Thomas; Hamm, Bernd; Gebauer, Bernhard; Wieners, Gero

    2017-10-01

    To evaluate detectability of hepatocellular carcinoma (HCC) using split-bolus cone-beam CT in intraindividual comparison between cone-beam CT and contrast-enhanced MR imaging. In a retrospective, single-center study, 28 patients with 85 HCC tumors were treated with transarterial chemoembolization between May 2015 and June 2016. All patients underwent arterial and hepatobiliary phase (HBP) MR imaging within 1 month before transarterial chemoembolization. Cone-beam CT images were acquired using a split-bolus contrast injection with 2 contrast injections and 1 cone-beam CT acquisition. Statistical analyses included Friedman 2-way analysis, Kendall coefficient of concordance, and Wilcoxon test. Tumor detectability was scored using a 5-point system (1 = best; 5 = worst) by 2 independent readers resulting in 170 evaluated tumors. Quantitative analysis included signal-to-noise and contrast-to-noise ratio and contrast measurements. P values cone-beam CT (2.91/2.73) and HBP MR imaging (2.93/2.21) compared with arterial MR imaging (3.72/3.05; P cone-beam CT and HBP MR imaging in terms of detectability (P = .154) and sensitivity for hypervascularized tumors. More tumors were identified on cone-beam CT (n = 121/170) than on arterial MR imaging (n = 94/170). Average contrast-to-noise ratio values of arterial and HBP MR imaging were higher than for cone-beam CT (7.79, 8.58, 4.43), whereas contrast values were higher for cone-beam CT than for MR imaging (0.11, 0.13, 0.97). Split-bolus cone-beam CT showed excellent detectability of HCC. Sensitivity is comparable to HBP MR imaging and better than arterial phase MR imaging. Copyright © 2017 SIR. Published by Elsevier Inc. All rights reserved.

  3. Near-Infrared and Optical Beam Steering and Frequency Splitting in Air-Holes-in-Silicon Inverse Photonic Crystals

    Science.gov (United States)

    2017-01-01

    We present the design of a dielectric inverse photonic crystal structure that couples line-defect waveguide propagating modes into highly directional beams of controllable directionality. The structure utilizes a triangular lattice made of air holes drilled in an infinitely thick Si slab, and it is designed for operation in the near-infrared and optical regime. The structure operation is based on the excitation and manipulation of dark dielectric surface states, in particular on the tailoring of the dark states’ coupling to outgoing radiation. This coupling is achieved with the use of properly designed external corrugations. The structure adapts and matches modes that travel through the photonic crystal and the free space. Moreover it facilitates the steering of the outgoing waves, is found to generate well-defined, spatially and spectrally isolated beams, and may serve as a frequency splitting component designed for operation in the near-infrared regime and in particular the telecom optical wavelength band. The design complies with the state-of-the-art Si nanofabrication technology and can be directly scaled for operation in the optical regime. PMID:29541653

  4. Calibration of atomic force microscope cantilevers using standard and inverted static methods assisted by FIB-milled spatial markers.

    Science.gov (United States)

    Slattery, Ashley D; Blanch, Adam J; Quinton, Jamie S; Gibson, Christopher T

    2013-01-11

    Static methods to determine the spring constant of AFM cantilevers have been widely used in the scientific community since the importance of such calibration techniques was established nearly 20 years ago. The most commonly used static techniques involve loading a trial cantilever with a known force by pressing it against a pre-calibrated standard or reference cantilever. These reference cantilever methods have a number of sources of uncertainty, which include the uncertainty in the measured spring constant of the standard cantilever, the exact position of the loading point on the reference cantilever and how closely the spring constant of the trial and reference cantilever match. We present a technique that enables users to minimize these uncertainties by creating spatial markers on reference cantilevers using a focused ion beam (FIB). We demonstrate that by combining FIB spatial markers with an inverted reference cantilever method, AFM cantilevers can be accurately calibrated without the tip of the test cantilever contacting a surface. This work also demonstrates that for V-shaped cantilevers it is possible to determine the precise loading position by AFM imaging the section of the cantilever where the two arms join. Removing tip-to-surface contact in both the reference cantilever method and sensitivity calibration is a significant improvement, since this is an important consideration for AFM users that require the imaging tip to remain in pristine condition before commencing measurements. Uncertainties of between 5 and 10% are routinely achievable with these methods.

  5. In-beam measurement of the hydrogen hyperfine splitting and prospects for antihydrogen spectroscopy

    Science.gov (United States)

    Diermaier, M.; Jepsen, C. B.; Kolbinger, B.; Malbrunot, C.; Massiczek, O.; Sauerzopf, C.; Simon, M. C.; Zmeskal, J.; Widmann, E.

    2017-06-01

    Antihydrogen, the lightest atom consisting purely of antimatter, is an ideal laboratory to study the CPT symmetry by comparison with hydrogen. With respect to absolute precision, transitions within the ground-state hyperfine structure (GS-HFS) are most appealing by virtue of their small energy separation. ASACUSA proposed employing a beam of cold antihydrogen atoms in a Rabi-type experiment, to determine the GS-HFS in a field-free region. Here we present a measurement of the zero-field hydrogen GS-HFS using the spectroscopy apparatus of ASACUSA's antihydrogen experiment. The measured value of νHF=1,420,405,748.4(3.4) (1.6) Hz with a relative precision of 2.7 × 10-9 constitutes the most precise determination of this quantity in a beam and verifies the developed spectroscopy methods for the antihydrogen HFS experiment to the p.p.b. level. Together with the recently presented observation of antihydrogen atoms 2.7 m downstream of the production region, the prerequisites for a measurement with antihydrogen are now available within the ASACUSA collaboration.

  6. In-beam measurement of the hydrogen hyperfine splitting and prospects for antihydrogen spectroscopy.

    Science.gov (United States)

    Diermaier, M; Jepsen, C B; Kolbinger, B; Malbrunot, C; Massiczek, O; Sauerzopf, C; Simon, M C; Zmeskal, J; Widmann, E

    2017-06-12

    Antihydrogen, the lightest atom consisting purely of antimatter, is an ideal laboratory to study the CPT symmetry by comparison with hydrogen. With respect to absolute precision, transitions within the ground-state hyperfine structure (GS-HFS) are most appealing by virtue of their small energy separation. ASACUSA proposed employing a beam of cold antihydrogen atoms in a Rabi-type experiment, to determine the GS-HFS in a field-free region. Here we present a measurement of the zero-field hydrogen GS-HFS using the spectroscopy apparatus of ASACUSA's antihydrogen experiment. The measured value of ν HF =1,420,405,748.4(3.4) (1.6) Hz with a relative precision of 2.7 × 10 -9 constitutes the most precise determination of this quantity in a beam and verifies the developed spectroscopy methods for the antihydrogen HFS experiment to the p.p.b. level. Together with the recently presented observation of antihydrogen atoms 2.7 m downstream of the production region, the prerequisites for a measurement with antihydrogen are now available within the ASACUSA collaboration.

  7. Cantilever torque magnetometry on coordination compounds

    DEFF Research Database (Denmark)

    Perfetti, Mauro

    2017-01-01

    Cantilever Torque Magnetometry (CTM) is one of the leading techniques to deeply understand magnetic anisotropy of coordination compounds. The knowledge of magnetic anisotropy is a mandatory requirement before proceeding with any future application related to the magnetic properties of coordination...... quantum phenomena such as magnetization steps and molecular hysteresis curves. Moreover, it can also provide the energy levels splitting and avefunctions composition, especially if coupled with microwave radiation....... compounds, such as quantum computation or information storage. This review enlightens that CTM offers a unique combination of accuracy and precision to disentangle noncollinear contributions inside Single Crystals as well as the sensitivity to detect molecular order of thin films. CTM can also detect...

  8. Split-beam echo sounder observations of natural methane seep variability in the northern Gulf of Mexico

    Science.gov (United States)

    Jerram, Kevin; Weber, Thomas C.; Beaudoin, Jonathan

    2015-03-01

    A method for positioning and characterizing plumes of bubbles from marine gas seeps using an 18 kHz scientific split-beam echo sounder (SBES) was developed and applied to acoustic observations of plumes of presumed methane gas bubbles originating at approximately 1400 m depth in the northern Gulf of Mexico. A total of 161 plume observations from 27 repeat surveys were grouped by proximity into 35 clusters of gas vent positions on the seafloor. Profiles of acoustic target strength per vertical meter of plume height were calculated with compensation for both the SBES beam pattern and the geometry of plume ensonification. These profiles were used as indicators of the relative fluxes and fates of gas bubbles acoustically observable at 18 kHz and showed significant variability between repeat observations at time intervals of 1 h-7.5 months. Active gas venting was observed during approximately one third of the survey passes at each cluster. While gas flux is not estimated directly in this study owing to lack of bubble size distribution data, repeat surveys at active seep sites showed variations in acoustic response that suggest relative changes in gas flux of up to 1 order of magnitude over time scales of hours. The minimum depths of acoustic plume observations at 18 kHz averaged 875 m and frequently coincided with increased amplitudes of acoustic returns in layers of biological scatterers, suggesting acoustic masking of the gas bubble plumes in these layers. Minimum plume depth estimates were limited by the SBES field of view in only five instances.

  9. Graphene cantilever under Casimir force

    Science.gov (United States)

    Derras-Chouk, Amel; Chudnovsky, Eugene M.; Garanin, Dmitry A.; Jaafar, Reem

    2018-05-01

    The stability of graphene cantilever under Casimir attraction to an underlying conductor is investigated. The dependence of the instability threshold on temperature and flexural rigidity is obtained. Analytical work is supplemented by numerical computation of the critical temperature above which the graphene cantilever irreversibly bends down and attaches to the conductor. The geometry of the attachment and exfoliation of the graphene sheet is discussed. It is argued that graphene cantilever can be an excellent tool for precision measurements of the Casimir force.

  10. A new approach to integrate PLZT thin films with micro-cantilevers

    Indian Academy of Sciences (India)

    Home; Journals; Sadhana; Volume 34; Issue 4. A new approach to integrate PLZT thin films with micro-cantilevers ... Different types of cantilever beams incorporating PLZT films have been successfully fabricated using 'lift-off' process and bulk micromachining technology. The proposed process can be advantageously ...

  11. Multi-directional energy harvesting by piezoelectric cantilever-pendulum with internal resonance

    Energy Technology Data Exchange (ETDEWEB)

    Xu, J.; Tang, J., E-mail: jtang@engr.uconn.edu [Department of Mechanical Engineering, The University of Connecticut, Storrs, Connecticut 06269 (United States)

    2015-11-23

    This letter reports a piezoelectric cantilever-pendulum design for multi-directional energy harvesting. A pendulum is attached to the tip of a piezoelectric cantilever-type energy harvester. This design aims at taking advantage of the nonlinear coupling between the pendulum motion in 3-dimensional space and the beam bending vibration at resonances. Experimental studies indicate that, under properly chosen parameters, 1:2 internal resonance can be induced, which enables the multi-directional energy harvesting with a single cantilever. The advantages of the design with respect to traditional piezoelectric cantilever are examined.

  12. Structural Optimization of Steel Cantilever Used in Concrete Box Girder Bridge Widening

    Directory of Open Access Journals (Sweden)

    Qian Wang

    2015-01-01

    Full Text Available The structural optimization method of steel cantilever used in concrete box girder bridge widening is illustrated in this paper. The structural optimization method of steel cantilever incorporates the conceptual layout design of steel cantilever beam based on the topological theory and the determination of the optimal location of the transverse external prestressed tendons which connect the steel cantilever and the box girder. The optimal design theory and the analysis process are illustrated. The mechanical model for the prestressed steel cantilever is built and the analytical expression of the optimal position of the transverse external tendon is deduced. At last the effectiveness of this method is demonstrated by the design of steel cantilevers which are used to widen an existing bridge.

  13. Integrated optical read-out for polymeric cantilever-based sensors

    DEFF Research Database (Denmark)

    Tenje, Maria

    2007-01-01

    This thesis presents a novel read-out method developed for cantilever-based sensors. Cantilevers are thin beams clamped at one end and during the last 10 years they have emerged as an interesting new type of bio/chemical sensor. The specific recognition of a chemical manifests itself as a bending...... of the cantilever from the generated surface stress. Conventionally the read-out used for this type of sensors is external and thereby very bulky. It is beneficial to fabricate a miniaturised system. Moreover, improved sensitivity is obtained by fabricating the cantilever in a polymeric material that has a low...... Young’s modulus instead of the conventional materials Si and Si3N4. Here, a novel read-out method is presented where optical waveguides are used to integrate the light into the cantilever. It is an all-polymer device where both the cantilever and the waveguides are fabricated in the negative resist SU-8...

  14. Experimental and Numerical Study of Damaged Cantilever

    DEFF Research Database (Denmark)

    Rytter, A.; Krawczuk, M.; Kirkegaard, Poul Henning

    2000-01-01

    of the results from experimental and numerical tests with hollow section cantileves containing fatigue cracks. Two different finite-element (FE) models have been used to estimate the modal parameters numerically. The first FE model consists of beam elements. The second FE model consists of traditional...... rectangular shell elements and one rectangular shell element with a transverse, internal, open crack. The analytical results from the numerical models are compared with data obtained from experimental tests. The numerical models give good agreements with the experimental data. The beam model takes...... into account only the first mode of the crack evaluation. In the shell model all three modes of the crack growth are taken into account. Nevertheless, the results obtained for both models are satisfactory because the beam is subjected to bending. It can be concluded that it is sufficient to use crack models...

  15. Stress evolution during growth of InAs on GaAs measured by an in-situ cantilever beam setup

    Energy Technology Data Exchange (ETDEWEB)

    Hu Dongzhi

    2007-02-13

    The influence of stress on the growth of InAs on GaAs(001) by molecular beam epitaxy (MBE) is investigated in this thesis. Film force curves were measured for InAs deposition under As-rich as well as In-rich growth conditions. The growth under As-rich conditions proceeds in the Stranski- Krastanov growth mode, meaning that quantum dots are formed after the initial growth of a wetting layer. During subsequent growth interruptions or intentional annealing at the growth temperature, the quantum dots undergo ripening. This growth mode of InAs films and the subsequent annealing behavior were studied in detail in this thesis. To understand the influence of strain on the growth mechanisms, the film force curves were analyzed and correlated to the morphological evolution of the InAs films during deposition and especially during annealing. Models were developed to fit and explain the relaxation of the film force measured during the annealing of InAs quantum dots. At temperatures lower than 470 C, quantum dots undergo standard Ostwald ripening. Different mechanisms, such as kinetic and diffusion limited, determine the ripening process. Fits of models based on these mechanisms to the film force relaxation curves, show, that although the relaxation curve for annealing at 440 C can be fitted reasonably well with all the models, the model describing ripening limited by the diffusion along dot boundaries yields a slightly better fit. The relaxation curves obtained at 455 C and 470 C can be fitted very well only with the model in which the ripening is controlled by the attachment/detachment of atoms on the dot surface. Annealing of quantum dots at temperatures higher than 500 C shows a very different behavior. Atomic force microscopy images reveal that the quantum dots ripen first and then dissolve after 450 s-600 s annealing. (orig.)

  16. Stress evolution during growth of InAs on GaAs measured by an in-situ cantilever beam setup

    International Nuclear Information System (INIS)

    Hu Dongzhi

    2007-01-01

    The influence of stress on the growth of InAs on GaAs(001) by molecular beam epitaxy (MBE) is investigated in this thesis. Film force curves were measured for InAs deposition under As-rich as well as In-rich growth conditions. The growth under As-rich conditions proceeds in the Stranski- Krastanov growth mode, meaning that quantum dots are formed after the initial growth of a wetting layer. During subsequent growth interruptions or intentional annealing at the growth temperature, the quantum dots undergo ripening. This growth mode of InAs films and the subsequent annealing behavior were studied in detail in this thesis. To understand the influence of strain on the growth mechanisms, the film force curves were analyzed and correlated to the morphological evolution of the InAs films during deposition and especially during annealing. Models were developed to fit and explain the relaxation of the film force measured during the annealing of InAs quantum dots. At temperatures lower than 470 C, quantum dots undergo standard Ostwald ripening. Different mechanisms, such as kinetic and diffusion limited, determine the ripening process. Fits of models based on these mechanisms to the film force relaxation curves, show, that although the relaxation curve for annealing at 440 C can be fitted reasonably well with all the models, the model describing ripening limited by the diffusion along dot boundaries yields a slightly better fit. The relaxation curves obtained at 455 C and 470 C can be fitted very well only with the model in which the ripening is controlled by the attachment/detachment of atoms on the dot surface. Annealing of quantum dots at temperatures higher than 500 C shows a very different behavior. Atomic force microscopy images reveal that the quantum dots ripen first and then dissolve after 450 s-600 s annealing. (orig.)

  17. Shear force microscopy using piezoresistive cantilevers in surface metrology

    Science.gov (United States)

    Gotszalk, Teodor; Kopiec, Daniel; Sierakowski, Andrzej; Janus, Paweł; Grabiec, Piotr; Rangelow, Ivo W.

    2014-09-01

    In this article we describe application of piezoresistive cantilevers in surface investigations carried out with the use of shear force microscopy (ShFM). The novel piezoresistive cantilevers integrate a Wheatstone piezoresistive bridge was used to detect the cantilever deflection, thermal deflection detector and planar tip protruding out of the spring beam. Because the planar tip deflection can be detected and controlled electronically the described technology is very flexible and can be applied in many surface investigations. In this article we will present operation theory of the described solution, experimental setup, methods for calibration of the tip deflection detection and actuation The analysis will be illustrated with example results of topography measurements performed using the described technology.

  18. Efficiency Enhancement of a Cantilever-Based Vibration Energy Harvester

    Directory of Open Access Journals (Sweden)

    Ali E. Kubba

    2013-12-01

    Full Text Available Extracting energy from ambient vibration to power wireless sensor nodes has been an attractive area of research, particularly in the automotive monitoring field. This article reports the design, analysis and testing of a vibration energy harvesting device based on a miniature asymmetric air-spaced cantilever. The developed design offers high power density, and delivers electric power that is sufficient to support most wireless sensor nodes for structural health monitoring (SHM applications. The optimized design underwent three evolutionary steps, starting from a simple cantilever design, going through an air-spaced cantilever, and ending up with an optimized air-spaced geometry with boosted power density level. Finite Element Analysis (FEA was used as an initial tool to compare the three geometries’ stiffness (K, output open-circuit voltage (Vave, and average normal strain in the piezoelectric transducer (εave that directly affect its output voltage. Experimental tests were also carried out in order to examine the energy harvesting level in each of the three designs. The experimental results show how to boost the power output level in a thin air-spaced cantilever beam for energy within the same space envelope. The developed thin air-spaced cantilever (8.37 cm3, has a maximum power output of 2.05 mW (H = 29.29 μJ/cycle.

  19. Cost-effective mapping of benthic habitats in inland reservoirs through split-beam sonar, indicator kriging, and historical geologic data.

    Directory of Open Access Journals (Sweden)

    Erik R Venteris

    Full Text Available Because bottom substrate composition is an important control on the temporal and spatial location of the aquatic community, accurate maps of benthic habitats of inland lakes and reservoirs provide valuable information to managers, recreational users, and scientists. Therefore, we collected vertical, split-beam sonar data (roughness [E1], hardness [E2], and bathymetry and sediment samples to make such maps. Statistical calibration between sonar parameters and sediment classes was problematic because the E1:E2 ratios for soft (muck and clay sediments overlapped a lower and narrower range for hard (gravel substrates. Thus, we used indicator kriging (IK to map the probability that unsampled locations did not contain coarse sediments. To overcome the calibration issue we tested proxies for the natural processes and anthropogenic history of the reservoir as potential predictive variables. Of these, a geologic map proved to be the most useful. The central alluvial valley and mudflats contained mainly muck and organic-rich clays. The surrounding glacial till and shale bedrock uplands contained mainly poorly sorted gravels. Anomalies in the sonar data suggested that the organic-rich sediments also contained trapped gases, presenting additional interpretive issues for the mapping. We extended the capability of inexpensive split-beam sonar units through the incorporation of historic geologic maps and other records as well as validation with dredge samples. Through the integration of information from multiple data sets, were able to objectively identify bottom substrate and provide reservoir users with an accurate map of available benthic habitat.

  20. Cost-effective mapping of benthic habitats in inland reservoirs through split-beam sonar, indicator kriging, and historical geologic data.

    Science.gov (United States)

    Venteris, Erik R; May, Cassandra J

    2014-01-01

    Because bottom substrate composition is an important control on the temporal and spatial location of the aquatic community, accurate maps of benthic habitats of inland lakes and reservoirs provide valuable information to managers, recreational users, and scientists. Therefore, we collected vertical, split-beam sonar data (roughness [E1], hardness [E2], and bathymetry) and sediment samples to make such maps. Statistical calibration between sonar parameters and sediment classes was problematic because the E1:E2 ratios for soft (muck and clay) sediments overlapped a lower and narrower range for hard (gravel) substrates. Thus, we used indicator kriging (IK) to map the probability that unsampled locations did not contain coarse sediments. To overcome the calibration issue we tested proxies for the natural processes and anthropogenic history of the reservoir as potential predictive variables. Of these, a geologic map proved to be the most useful. The central alluvial valley and mudflats contained mainly muck and organic-rich clays. The surrounding glacial till and shale bedrock uplands contained mainly poorly sorted gravels. Anomalies in the sonar data suggested that the organic-rich sediments also contained trapped gases, presenting additional interpretive issues for the mapping. We extended the capability of inexpensive split-beam sonar units through the incorporation of historic geologic maps and other records as well as validation with dredge samples. Through the integration of information from multiple data sets, were able to objectively identify bottom substrate and provide reservoir users with an accurate map of available benthic habitat.

  1. Embryo splitting

    OpenAIRE

    Karl Illmensee; Mike Levanduski

    2010-01-01

    Mammalian embryo splitting has successfully been established in farm animals. Embryo splitting is safely and efficiently used for assisted reproduction in several livestock species. In the mouse, efficient embryo splitting as well as single blastomere cloning have been developed in this animal system. In nonhuman primates embryo splitting has resulted in several pregnancies. Human embryo splitting has been reported recently. Microsurgical embryo splitting under Institutional Review Board appr...

  2. Embryo splitting

    Directory of Open Access Journals (Sweden)

    Karl Illmensee

    2010-04-01

    Full Text Available Mammalian embryo splitting has successfully been established in farm animals. Embryo splitting is safely and efficiently used for assisted reproduction in several livestock species. In the mouse, efficient embryo splitting as well as single blastomere cloning have been developed in this animal system. In nonhuman primates embryo splitting has resulted in several pregnancies. Human embryo splitting has been reported recently. Microsurgical embryo splitting under Institutional Review Board approval has been carried out to determine its efficiency for blastocyst development. Embryo splitting at the 6–8 cell stage provided a much higher developmental efficiency compared to splitting at the 2–5 cell stage. Embryo splitting may be advantageous for providing additional embryos to be cryopreserved and for patients with low response to hormonal stimulation in assisted reproduction programs. Social and ethical issues concerning embryo splitting are included regarding ethics committee guidelines. Prognostic perspectives are presented for human embryo splitting in reproductive medicine.

  3. Micro-cantilever flow sensor for small aircraft

    KAUST Repository

    Ghommem, Mehdi

    2013-10-01

    We extend the use of cantilever beams as flow sensors for small aircraft. As such, we propose a novel method to measure the airspeed and the angle of attack at which the air travels across a small flying vehicle. We measure beam deflections and extract information about the surrounding flow. Thus, we couple a nonlinear beam model with a potential flow simulator through a fluid-structure interaction scheme. We use this numerical approach to generate calibration curves that exhibit the trend for the variations of the limit cycle oscillations amplitudes of flexural and torsional vibrations with the air speed and the angle of attack, respectively. © The Author(s) 2013.

  4. Design of cantilever probes for Atomic Force Microscopy (AFM)

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2000-01-01

    A cantilever beam used in an Atomic Force Microscope is optimized with respect to two different objectives. The first goal is to maximize the first eigenfrequency while keeping the stiffness of the probe constant. The second goal is to maximize the tip angle of the first eigenmode while again...... keeping the stiffness constant. The resulting design of the beam from the latter optimization gives almost the same result as when maximizing the first eigenfrequency. Adding a restriction on the second eigenfrequency result in a significant change of the optimal design. The beam is modelled with 12 DOF...

  5. Calibration and examination of piezoresistive Wheatstone bridge cantilevers for scanning probe microscopy.

    Science.gov (United States)

    Gotszalk, Teodor; Grabiec, Piotr; Rangelow, Ivo W

    2003-01-01

    This paper describes the method of determining the force constant and displacement sensitivity of piezoresistive Wheatstone bridge cantilevers applied in scanning probe microscopy (SPM). In the procedure presented here, the force constant for beams with various geometry is determined based on resonance frequency measurement. The displacement sensitivity is measured by the deflection of the cantilever with the calibrated piezoactuator stage. Preliminary results show that our method is capable of measuring the force constant of Wheatstone bridge cantilevers with an accuracy of better than 5% and this is used as feedback for improvement of sensor micromachining process.

  6. Cantilever-like micromechanical sensors

    DEFF Research Database (Denmark)

    Boisen, Anja; Dohn, Søren; Keller, Stephan Sylvest

    2011-01-01

    The field of cantilever-based sensing emerged in the mid-1990s and is today a well-known technology for label-free sensing which holds promise as a technique for cheap, portable, sensitive and highly parallel analysis systems. The research in sensor realization as well as sensor applications has...... increased significantly over the past 10 years. In this review we will present the basic modes of operation in cantilever-like micromechanical sensors and discuss optical and electrical means for signal transduction. The fundamental processes for realizing miniaturized cantilevers are described with focus...... on silicon-and polymer-based technologies. Examples of recent sensor applications are given covering such diverse fields as drug discovery, food diagnostics, material characterizations and explosives detection....

  7. Polymeric Cantilever Arrays for Biosensing Applications

    DEFF Research Database (Denmark)

    Calleja, M.; Tamayo, J.; Johansson, Alicia

    2003-01-01

    We report the fabrication of arrays of polymeric cantilevers for biochemistry applications. The cantilevers are fabricated in the polymer SU-8. The use of a polymer as the component material for the cantilevers provides the sensors with very high sensitivity due to convenient mechanical material...

  8. Seafloor multibeam backscatter calibration experiment: comparing 45°-tilted 38-kHz split-beam echosounder and 30-kHz multibeam data

    Science.gov (United States)

    Ladroit, Yoann; Lamarche, Geoffroy; Pallentin, Arne

    2017-12-01

    Obtaining absolute seafloor backscatter measurements from hydrographic multibeam echosounders is yet to be achieved. We propose a low-cost experiment to calibrate the various acquisition modes of a 30-kHz Kongsberg EM 302 multibeam echosounder in a range of water depths. We use a 38-kHz Simrad EK60 calibrated fisheries split-beam echosounder mounted at 45° angle on the vessel's hull as a reference for the calibration. The processing to extract seafloor backscatter from the EK60 requires bottom detection, ray tracing and motion compensation to obtain acceptable geo-referenced backscatter measurements from this non-hydrographic system. Our experiment was run in Cook Strait, New Zealand, on well-known seafloor patches in shallow, mid, and deep-water depths. Despite acquisition issues due to weather, our results demonstrate the strong potential of such an approach to obtain system's absolute calibration which is required for quantitative use of backscatter strength data.

  9. Performance Analysis of Wind-Induced Piezoelectric Vibration Bimorph Cantilever for Rotating Machinery

    Directory of Open Access Journals (Sweden)

    Gongbo Zhou

    2015-01-01

    Full Text Available Harvesting the energy contained in the running environment of rotating machinery would be a good way to supplement energy to the wireless sensor. In this paper, we take piezoelectric bimorph cantilever beam with parallel connection mode as energy collector and analyze the factors which can influence the generation performance. First, a modal response theory model is built. Second, the static analysis, modal analysis, and piezoelectric harmonic response analysis of the wind-induced piezoelectric bimorph cantilever beam are given in detail. Finally, an experiment is also conducted. The results show that wind-induced piezoelectric bimorph cantilever beam has low resonant frequency and stable output under the first modal mode and can achieve the maximum output voltage under the resonant condition. The output voltage increases with the increase of the length and width of wind-induced piezoelectric bimorph cantilever beam, but the latter increasing amplitude is relatively smaller. In addition, the output voltage decreases with the increase of the thickness and the ratio of metal substrate to piezoelectric patches thickness. The experiment showed that the voltage amplitude generated by the piezoelectric bimorph cantilever beam can reach the value simulated in ANSYS, which is suitable for actual working conditions.

  10. Performance evaluation of perforated micro-cantilevers for MEMS applications

    Science.gov (United States)

    Swamy, Kenkere Balashanthamurthy Mruthyunjaya; Mukherjee, Banibrata; Ali Syed Mohammed, Zishan; Chakraborty, Suman; Sen, Siddhartha

    2014-04-01

    Miniaturized cantilevers are one of the elementary structures that are widely used in many micro-devices and systems. The dynamic performance of micro-cantilevers having process dictated through perforations is investigated. High-aspect ratio, long silicon cantilevers, intended for improved performance through lowered stiffness are designed with a series of through holes and simulated along with similar nonperforated/solid cantilevers for comparison. A few perforated structures are also fabricated using silicon-on-insulator-based multiproject MEMS processes from MEMSCAP Inc. (Durham, North Carolina) by reduced mask level and eliminating complex substrate trenching step. The dynamic behavior of these fabricated structures is experimentally studied for both in-plane and out-of-plane directions. It is shown that, due to the presence of perforations, stiffness in planar direction is lightly affected, whereas in out-of-plane direction it is significantly reduced by >35%. Similarly, the variation of damping in both perforated and nonperforated beams, too, is thoroughly analyzed for the first few modes of vibration. Nevertheless, their frequency response variation of micro-systems including those based on comb drives.

  11. A new approach for elasto-plastic finite strain analysis of cantilever ...

    Indian Academy of Sciences (India)

    GЦKHAN T TAYYAR

    Curvature; deflection curve; cantilever beam; elasto-plastic analysis; tapered beam subjected to tip moment; kinematic deflection theory. 1. Introduction. The objective in second-order static structural analysis is to determine the balance of internal and external forces throughout the deformed configuration of a structure until.

  12. In vitro evaluation of failure loads of nonmetal cantilevered resin-bonded fixed dental prostheses

    NARCIS (Netherlands)

    van Dalen, A.; Feilzer, A.J.; Kleverlaan, C.J.

    2008-01-01

    Purpose: To evaluate in vitro the influence of fiber reinforcement on the failure loads of resin composite beams, simulating cantilevered two-unit resin-bonded fixed dental prostheses, and compare the results with similarly obtained failure loads of ZrO2 and CoCr beams of a comparable design.

  13. Cantilevered probe detector with piezoelectric element

    Science.gov (United States)

    Adams, Jesse D; Sulchek, Todd A; Feigin, Stuart C

    2013-04-30

    A disclosed chemical detection system for detecting a target material, such as an explosive material, can include a cantilevered probe, a probe heater coupled to the cantilevered probe, and a piezoelectric element disposed on the cantilevered probe. The piezoelectric element can be configured as a detector and/or an actuator. Detection can include, for example, detecting a movement of the cantilevered probe or a property of the cantilevered probe. The movement or a change in the property of the cantilevered probe can occur, for example, by adsorption of the target material, desorption of the target material, reaction of the target material and/or phase change of the target material. Examples of detectable movements and properties include temperature shifts, impedance shifts, and resonant frequency shifts of the cantilevered probe. The overall chemical detection system can be incorporated, for example, into a handheld explosive material detection system.

  14. Cantilevered probe detector with piezoelectric element

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Jesse D; Sulchek, Todd A; Feigin, Stuart C

    2014-04-29

    A disclosed chemical detection system for detecting a target material, such as an explosive material, can include a cantilevered probe, a probe heater coupled to the cantilevered probe, and a piezoelectric element disposed on the cantilevered probe. The piezoelectric element can be configured as a detector and/or an actuator. Detection can include, for example, detecting a movement of the cantilevered probe or a property of the cantilevered probe. The movement or a change in the property of the cantilevered probe can occur, for example, by adsorption of the target material, desorption of the target material, reaction of the target material and/or phase change of the target material. Examples of detectable movements and properties include temperature shifts, impedance shifts, and resonant frequency shifts of the cantilevered probe. The overall chemical detection system can be incorporated, for example, into a handheld explosive material detection system.

  15. Calibration of the effective spring constant of ultra-short cantilevers for a high-speed atomic force microscope

    International Nuclear Information System (INIS)

    Song, Yun-Peng; Wu, Sen; Xu, Lin-Yan; Zhang, Jun-Ming; Fu, Xing; Hu, Xiao-Dong; Dorantes-Gonzalez, Dante J

    2015-01-01

    Ultra-short cantilevers are a new type of cantilever designed for the next generation of high-speed atomic force microscope (HS-AFM). Ultra-short cantilevers have smaller dimensions and higher resonant frequency than conventional AFM cantilevers. Moreover, their geometry may also be different from the conventional beam-shape or V-shape. These changes increase the difficulty of determining the spring constant for ultra-short cantilevers, and hence limit the accuracy and precision of force measurement based on a HS-AFM. This paper presents an experimental method to calibrate the effective spring constant of ultra-short cantilevers. By using a home-made AFM head, the cantilever is bent against an electromagnetic compensation balance under servo control. Meanwhile the bending force and the cantilever deflection are synchronously measured by the balance and the optical lever in the AFM head, respectively. Then the effective spring constant is simply determined as the ratio of the force to the corresponding deflection. Four ultra-short trapezoid shape cantilevers were calibrated using this method. A quantitative uncertainty analysis showed that the combined relative standard uncertainty of the calibration result is less than 2%, which is better than the uncertainty of any previously reported techniques. (paper)

  16. Piezoelectric Bimorph Cantilever for Vibration-Producing-Hydrogen

    Directory of Open Access Journals (Sweden)

    Guangming Cheng

    2012-12-01

    Full Text Available A device composed of a piezoelectric bimorph cantilever and a water electrolysis device was fabricated to realize piezoelectrochemical hydrogen production. The obvious output of the hydrogen and oxygen through application of a mechanical vibration of ~0.07 N and ~46.2 Hz was observed. This method provides a cost-effective, recyclable, environment-friendly and simple way to directly split water for hydrogen fuels by scavenging mechanical waste energy forms such as noise or traffic vibration in the environment.

  17. Spectral filter for splitting a beam with electromagnetic radiation having wavelengths in the extreme ultraviolet (EUV) or soft X-Ray (Soft X) and the infrared (IR) wavelength range

    NARCIS (Netherlands)

    van Goor, F.A.; Bijkerk, Frederik; van den Boogaard, Toine; van den Boogaard, A.J.R.; van der Meer, R.

    2012-01-01

    Spectral filter for splitting the primary radiation from a generated beam with primary electromagnetic radiation having a wavelength in the extreme ultraviolet (EUV radiation) or soft X-ray (soft X) wavelength range and parasitic radiation having a wavelength in the infrared wavelength range (IR

  18. Angularly symmetric splitting of a light beam upon reflection and refraction at an air-dielectric plane boundary: comment.

    Science.gov (United States)

    Andersen, Torben B

    2016-05-01

    In a recent paper, conditions for achieving equal and opposite angular deflections of a light beam by reflection and refraction at an interface between air and a dielectric were determined [J. Opt. Soc. Am. A32, 2436 (2015)JOAOD60740-323210.1364/JOSAA.32.002436]. The paper gives plots of angles of incidence and refraction as a function of the prism refractive index as well as plots of reflectances and incident linear-polarization azimuth angles as functions of the refractive index. We show here that it is possible to express these quantities as simple algebraic functions of the refractive index.

  19. Annihilation detector for an in-beam spectroscopy apparatus to measure the ground state hyperfine splitting of antihydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Sauerzopf, Clemens, E-mail: clemens.sauerzopf@oeaw.ac.at [Stefan Meyer Institute for subatomic Physics, Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Wien (Austria); Capon, Aaron A.; Diermaier, Martin; Fleck, Markus; Kolbinger, Bernadette [Stefan Meyer Institute for subatomic Physics, Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Wien (Austria); Malbrunot, Chloé [Stefan Meyer Institute for subatomic Physics, Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Wien (Austria); Organisation Européenne pour la Recherche Nucléaire (CERN), 1211 Geneva 23 (Switzerland); Massiczek, Oswald; Simon, Martin C.; Vamosi, Stefan; Zmeskal, Johann; Widmann, Eberhard [Stefan Meyer Institute for subatomic Physics, Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Wien (Austria)

    2017-02-11

    The matter-antimatter asymmetry observed in the universe today still lacks a quantitative explanation. One possible mechanism that could contribute to the observed imbalance is a violation of the combined Charge-, Parity- and Time symmetries (CPT). A test of CPT symmetry using anti-atoms is being carried out by the ASACUSA-CUSP collaboration at the CERN Antiproton Decelerator using a low temperature beam of antihydrogen—the most simple atomic system built only of antiparticles. While hydrogen is the most abundant element in the universe, antihydrogen is produced in very small quantities in a laboratory framework. A detector for in-beam measurements of the ground state hyperfine structure of antihydrogen has to be able to detect very low signal rates within high background. To fulfil this challenging task, a two layer barrel hodoscope detector was developed. It is built of plastic scintillators with double sided readout via Silicon Photomultipliers (SiPMs). The SiPM readout is done using novel, compact and cost efficient electronics that incorporate power supply, amplifier and discriminator on a single board. This contribution will evaluate the performance of the new hodoscope detector. - Highlights: • A novel detector for Antihydrogen was successfully commissioned. • A time of flight resolution of better than 1 ns was achieved. • Rudimentary 3D tracking is possible without bar segmentation.

  20. SU-8 cantilever chip interconnection

    DEFF Research Database (Denmark)

    Johansson, Alicia Charlotte; Janting, Jakob; Schultz, Peter

    2006-01-01

    the electrodes on the SU-8 chip to a printed circuit board. Here, we present two different methods of electrically connecting an SU-8 chip, which contains a microfluidic network and free-hanging mechanical parts. The tested electrical interconnection techniques are flip chip bonding using underfill or flip chip...... bonding using an anisotropic conductive film (ACF). These are both widely used in the Si industry and might also be used for the large scale interconnection of SU-8 chips. The SU-8 chip, to which the interconnections are made, has a microfluidic channel with integrated micrometer-sized cantilevers...... that can be used for label-free biochemical detection. All the bonding tests are compared with results obtained using similar Si chips. It is found that it is significantly more complicated to interconnect SU-8 than Si cantilever chips primarily due to the softness of SU-8....

  1. Characterizing Vibrating Cantilevers for Liquid Viscosity and Density Sensing

    Directory of Open Access Journals (Sweden)

    Bernhard Jakoby

    2008-10-01

    Full Text Available Miniaturized liquid sensors are essential devices in online process or condition monitoring. In case of viscosity and density sensing, microacoustic sensors such as quartz crystal resonators or SAW devices have proved particularly useful. However, these devices basically measure a thin-film viscosity, which is often not comparable to the macroscopic parameters probed by conventional viscometers. Miniaturized cantilever-based devices are interesting alternatives for such applications, but here the interaction between the liquid and the oscillating beam is more involved. In our contribution, we describe a measurement setup, which allows the investigation of this interaction for different beam cross-sections. We present an analytical model based on an approximation of the immersed cantilever as an oscillating sphere comprising the effective mass and the intrinsic damping of the cantilever and additional mass and damping due to the liquid loading. The model parameters are obtained from measurements with well-known sample liquids by a curve fitting procedure. Finally, we present the measurement of viscosity and density of an unknown sample liquid, demonstrating the feasibility of the model.

  2. The generation of a complete spiral spot and multi split rings by focusing three circularly polarized vortex beams

    Science.gov (United States)

    Chen, Jiannong; Gao, Xiumin; Zhu, Linwei; Xu, Qinfeng; Ma, Wangzi

    2014-05-01

    We demonstrate that a complete right-handed or left-handed spiral-shaped focus can be created by focusing circularly polarized and three spatially shifted vortex beams through high numerical objective. By dividing the back aperture into multi annular zones and applying an additional phase term, the multi focal spots aligned along z axis of individual three dimensional focal shapes can be generated. The spiral shaped focus provides a pathway of manipulating the micro-particles in a curved trajectory and opens up a possibility of measuring mechanical torque of biological large molecules such as DNA by chemically binding one end on the cover-glass. The multi focal spots aligned along the z axis can eliminate the need of z axis scanning in the direct laser writing fabrication of some metamaterials which is composed of three-dimensional array of specific shapes of building blocks.

  3. Design & fabrication of cantilever array biosensors

    DEFF Research Database (Denmark)

    Boisen, Anja; Thundat, T

    2009-01-01

    of samples. Currently available fabrication technology will allow the integration of electronic readout and sample introduction into a single unit, decreasing the device size, detection time, and cost. Biosensing technologies based on microfabricated cantilever arrays involving multiple cantilevers......, electronic processing, and even local telemetry on a single chip have the potential of satisfying the need for highly sensitive and selective multiple-target detection in very small samples. Here we will review the design and fabrication process of cantilever-based biosensors....

  4. Cone-beam computed tomography evaluation on the condylar displacement following sagittal split ramus osteotomy in asymmetric setback patients: Comparison between conventional approach and surgery-first approach.

    Science.gov (United States)

    Oh, Min-Hee; Hwang, Hyeon-Shik; Lee, Kyung-Min; Cho, Jin-Hyoung

    2017-09-01

    To compare the condylar displacement following sagittal split ramus osteotomy (SSRO) in asymmetric setback patients between the conventional approach and surgery-first approach and to determine whether the condylar displacement is affected by asymmetric setback in SSRO patients. This was a retrospective study. The subjects consisted of patients with facial asymmetry who underwent SSRO and had cone-beam computed tomography taken before and 1 month after surgery. They were allocated into the conventional (n = 18) and surgery-first (SF) groups (n = 20). Descriptive, independent t-tests and Pearson correlation analysis were computed. The amount of condylar displacement in x-, y-, and z-directions and Euclidean distance showed no statistically significant differences between the conventional and SF groups. Comparing the postoperative condylar position with the preoperative position, the condylar displacement occurred in posterior (P groups except on the deviated side in the conventional group. The condylar displacement occurred in a posterior (P group. However, the condylar displacement in three dimensions showed no statistically significant differences between the two groups. In the correlation analysis, the condylar displacement in both the deviated and contralateral sides showed no significant correlation with asymmetric setback in either group. The condylar displacement in three dimensions and the distance of condylar displacement in SSRO patients with facial asymmetry showed no significant difference between conventional and SF groups. Condylar displacement was not associated with asymmetric setback.

  5. Electric-dipole moment of CaF by molecular-beam, laser-rf, double-resonance study of Stark splittings

    International Nuclear Information System (INIS)

    Childs, W.J.; Goodman, L.S.; Nielsen, U.; Pfeufer, V.

    1984-01-01

    The electronic structure of diatomic molecules is much more complex for open-shell sytems (radicals) than for the normal closed-shell systems, and the development of an adequate theoretical understanding will require a substantial upgrading of experimental knowledge in both quality and quantity. The alkaline-earth monohalide family of radicals, with only a single electron outside closed-shell cores, would appear to be a logical starting point for such studies, and there has been a great increase in work in this area in the last few years in spite of the special difficulties of working with free radicals. As the work of measuring the vibrational and rotational structure of the electronic states has become more complete, attention has turned to study of the much weaker spin-rotation and hyperfine interactions. Within the last three years, these interactions have been studied systematically at high precision in the calcium monohalide family with the molecular-beam, laser-rf double-resonance technique. The same method has now been modified and extended to make possible measurement of the electric-dipole moments of these molecules through observation of the Stark splittings of radiofrequency transitions. It is hoped that when considered together, the several types of data will make it possible to understand the ground-state electronic wave functions of these molecules at least qualitatively. 2 figures

  6. Analytical simulation of the cantilever-type energy harvester

    Directory of Open Access Journals (Sweden)

    Jie Mei

    2016-01-01

    Full Text Available This article describes an analytical model of the cantilever-type energy harvester based on Euler–Bernoulli’s beam theory. Starting from the Hamiltonian form of total energy equation, the bending mode shapes and electromechanical dynamic equations are derived. By solving the constitutive electromechanical dynamic equation, the frequency transfer function of output voltage and power can be obtained. Through a case study of a unimorph piezoelectric energy harvester, this analytical modeling method has been validated by the finite element method.

  7. Influence of rotation and pretwist on cantilever fan blade flutter

    Science.gov (United States)

    Sisto, F.; Chang, A. T.

    1985-01-01

    The fundamental and lowest frequency natural modes in a cantilever fan blade exhibit significant amounts of flexure and torsion coupled by pretwist and operation in a rotational force field. Consequently the flutter estimation of such blades requires an accurate structural description that incorporates these two effects, amongst others. A beam-type finite element model is used in this study with up to six spanwise elements, each element being pretwisted. Coalescence-type flutter is found with subsonic aerodynamics. Evidence of the aerodynamic resonance phenomenon is exhibited and the importance of including radially varying aerodynamic forces is brought out.

  8. Bandgap measurements and the peculiar splitting of E2H phonon modes of InxAl1-xN nanowires grown by plasma assisted molecular beam epitaxy

    KAUST Repository

    Tangi, Malleswararao

    2016-07-26

    The dislocation free Inx Al 1-xN nanowires (NWs) are grown on Si(111) by nitrogen plasma assisted molecular beam epitaxy in the temperature regime of 490 °C–610 °C yielding In composition ranges over 0.50 ≤ x ≤ 0.17. We study the optical properties of these NWs by spectroscopic ellipsometry (SE), photoluminescence, and Raman spectroscopies since they possesses minimal strain with reduced defects comparative to the planar films. The optical bandgap measurements of Inx Al 1-xN NWs are demonstrated by SE where the absorption edges of the NW samples are evaluated irrespective of substrate transparency. A systematic Stoke shift of 0.04–0.27 eV with increasing x was observed when comparing the micro-photoluminescence spectra with the Tauc plot derived from SE. The micro-Raman spectra in the NWs with x = 0.5 showed two-mode behavior for A1(LO) phonons and single mode behavior for E2 H phonons. As for x = 0.17, i.e., high Al content, we observed a peculiar E2 H phonon mode splitting. Further, we observe composition dependent frequency shifts. The 77 to 600 K micro-Raman spectroscopy measurements show that both AlN- and InN-like modes of A1(LO) and E2 H phonons in Inx Al 1-xN NWs are redshifted with increasing temperature, similar to that of the binary III group nitride semiconductors. These studies of the optical properties of the technologically important Inx Al 1-xN nanowires will path the way towards lasers and light-emitting diodes in the wavelength of the ultra-violet and visible range.

  9. Three-way flexible cantilever probes for static contact

    DEFF Research Database (Denmark)

    Wang, Fei; Petersen, Dirch Hjorth; Jensen, Helle Vendelbo

    2011-01-01

    In micro four-point probe measurements, three-way flexible L-shaped cantilever probes show significant advantages over conventional straight cantilever probes. The L-shaped cantilever allows static contact to the sample surface which reduces the frictional wear of the cantilever tips. We analyze...

  10. Experiments for possible hydroacoustic discrimination of free-swimming juvenile gadoid fish by analysis of broadband pulse spectra as well as 3D fish position form video images and split beam acoustics

    DEFF Research Database (Denmark)

    Lundgren, Bo; Nielsen, J. Rasmus

    2002-01-01

    Measurements were made of the broad-bandwidth (80–220 kHz) acoustic backscattering from free-swimming juvenile gadoids at various orientations and positions in an acoustic beam, under controlled conditions. The experimental apparatus consisted of a stereo-video camera system, a broad-bandwidth ec......Measurements were made of the broad-bandwidth (80–220 kHz) acoustic backscattering from free-swimming juvenile gadoids at various orientations and positions in an acoustic beam, under controlled conditions. The experimental apparatus consisted of a stereo-video camera system, a broad...... were estimated from stereo-images captured synchronously when broad-bandwidth echoes were received from passing fish. Fish positions were also estimated from data collected with a synchronized split-beam echosounder. Software was developed for image analysis and modelling, including calibration...

  11. Spring constant measurement using a MEMS force and displacement sensor utilizing paralleled piezoresistive cantilevers

    Science.gov (United States)

    Kohyama, Sumihiro; Takahashi, Hidetoshi; Yoshida, Satoru; Onoe, Hiroaki; Hirayama-Shoji, Kayoko; Tsukagoshi, Takuya; Takahata, Tomoyuki; Shimoyama, Isao

    2018-04-01

    This paper reports on a method to measure a spring constant on site using a micro electro mechanical systems (MEMS) force and displacement sensor. The proposed sensor consists of a force-sensing cantilever and a displacement-sensing cantilever. Each cantilever is composed of two beams with a piezoresistor on the sidewall for measuring the in-plane lateral directional force and displacement. The force resolution and displacement resolution of the fabricated sensor were less than 0.8 µN and 0.1 µm, respectively. We measured the spring constants of two types of hydrogel microparticles to demonstrate the effectiveness of the proposed sensor, with values of approximately 4.3 N m-1 and 15.1 N m-1 obtained. The results indicated that the proposed sensor is effective for on-site spring constant measurement.

  12. Variable RF capacitor based on a-Si:H (P-doped) multi-length cantilevers

    International Nuclear Information System (INIS)

    Fu, Y Q; Milne, S B; Luo, J K; Flewitt, A J; Wang, L; Miao, J M; Milne, W I

    2006-01-01

    A variable RF capacitor with a-Si:H (doped with phosphine) cantilevers as the top electrode were designed and fabricated. Because the top multi-cantilever electrodes have different lengths, increasing the applied voltage pulled down the cantilever beams sequentially, thus realizing a gradual increase of the capacitance with the applied voltage. A high-k material, H f O 2 , was used as an insulating layer to increase the tuning range of the capacitance. The measured capacitance from the fabricated capacitor was much lower and the pull-in voltage was much higher than those from theoretical analysis because of incomplete contact of the two electrodes, existence of film differential stresses and charge injection effect. Increase of sweeping voltage rate could significantly shift the pull-in voltage to higher values due to the charge injection mechanisms

  13. Investigation of static and dynamic behavior of functionally graded piezoelectric actuated Poly-Si micro cantilever probe

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Vibhuti Bhushan; Parashar, Sandeep Kumar, E-mail: skparashar@rtu.ac.in [Department of Mechanical Engineering, Rajasthan Technical University, Kota (India)

    2016-04-13

    In the present paper a novel functionally graded piezoelectric (FGP) actuated Poly-Si micro cantilever probe is proposed for atomic force microscope. The shear piezoelectric coefficient d{sub 15} has much higher value than coupling coefficients d{sub 31} and d{sub 33}, hence in the present work the micro cantilever beam actuated by d{sub 15} effect is utilized. The material properties are graded in the thickness direction of actuator by a simple power law. A three dimensional finite element analysis has been performed using COMSOL Multiphysics® (version 4.2) software. Tip deflection and free vibration analysis for the micro cantilever probe has been done. The results presented in the paper shall be useful in the design of micro cantilever probe and their subsequent utilization in atomic force microscopes.

  14. An Experimental and Theoretical Investigation of Electrostatically Coupled Cantilever Microbeams

    KAUST Repository

    Ilyas, Saad

    2016-06-16

    We present an experimental and theoretical investigation of the static and dynamic behavior of electrostatically coupled laterally actuated silicon microbeams. The coupled beam resonators are composed of two almost identical flexible cantilever beams forming the two sides of a capacitor. The experimental and theoretical analysis of the coupled system is carried out and compared against the results of beams actuated with fixed electrodes individually. The pull-in characteristics of the electrostatically coupled beams are studied, including the pull-in time. The dynamics of the coupled dual beams are explored via frequency sweeps around the neighborhood of the natural frequencies of the system for different input voltages. Good agreement is reported among the simulation results and the experimental data. The results show considerable drop in the pull-in values as compared to single microbeam resonators. The dynamics of the coupled beam resonators are demonstrated as a way to increase the bandwidth of the resonator near primary resonance as well as a way to introduce increased frequency shift, which can be promising for resonant sensing applications. Moreover the dynamic pull-in characteristics are also studied and proposed as a way to sense the shift in resonance frequency.

  15. Calibration of the torsional and lateral spring constants of cantilever sensors.

    Science.gov (United States)

    Parkin, John D; Hähner, Georg

    2014-06-06

    A method suitable for the calibration of the spring constants of all torsional and lateral eigenmodes of micro- and nanocantilever sensors is described. Such sensors enable nanomechanical measurements and the characterization of nanomaterials, for example with atomic force microscopy. The method presented involves the interaction of a flow of fluid from a microchannel with the cantilever beam. Forces imparted by the flow cause the cantilever to bend and induce a measurable change of the torsional and lateral resonance frequencies. From the frequency shifts the cantilever spring constants can be determined. The method does not involve physical contact between the cantilever or its tip and a hard surface. As such it is non-invasive and does not risk damage to the cantilever. Experimental data is presented for two rectangular microcantilevers with fundamental flexural spring constants of 0.046 and 0.154 N m(-1). The experimentally determined torsional stiffness values are compared with those obtained by the Sader method. We demonstrate that the torsional spring constants can be readily calibrated using the method with an accuracy of around 15%.

  16. Measurement and reliability issues in resonant mode cantilever for bio-sensing application in fluid medium

    Science.gov (United States)

    Kathel, G.; Shajahan, M. S.; Bhadra, P.; Prabhakar, A.; Chadha, A.; Bhattacharya, E.

    2016-09-01

    Cantilevers immersed in liquid experience viscous damping and hydrodynamic loading. We report on the use of such cantilevers, operating in the dynamic mode with, (i) frequency sweeping and (ii) phase locked loop methods. The solution to reliability issues such as random drift in the resonant peak values, and interference of spurious modes in the resonance frequency spectrum, are explained based on the actuation signal provided and laser spot size. The laser beam spot size and its position on the cantilever were found to have an important role, on the output signal and resonance frequency. We describe a method to distinguish the normal modes from the spurious modes for a cantilever. Uncertainties in the measurements define the lower limit of mass detection (m min). The minimum detection limits of the two measurement methods are investigated by measuring salt adsorption from phosphate buffer solution, as an example, a mass of 14 pg was measured using the 14th transverse mode of a 500~μ m  ×  100 μm  ×  1 μm silicon cantilever. The optimized measurement was used to study the interaction between antibody and antigen.

  17. Multi-resonant wideband energy harvester based on a folded asymmetric M-shaped cantilever

    International Nuclear Information System (INIS)

    Wu, Meng; Mao, Haiyang; Li, Zhigang; Liu, Ruiwen; Ming, Anjie; Ou, Yi; Ou, Wen

    2015-01-01

    This article reports a compact wideband piezoelectric vibration energy harvester consisting of three proof masses and an asymmetric M-shaped cantilever. The M-shaped beam comprises a main beam and two folded and dimension varied auxiliary beams interconnected through the proof mass at the end of the main cantilever. Such an arrangement constitutes a three degree-of-freedom vibrating body, which can tune the resonant frequencies of its first three orders close enough to obtain a utility wide bandwidth. The finite element simulation results and the experimental results are well matched. The operation bandwidth comprises three adjacent voltage peaks on account of the frequency interval shortening mechanism. The result shows that the proposed piezoelectric energy harvester could be efficient and adaptive in practical vibration circumstance based on multiple resonant modes

  18. A Mathematical Model for the Analysis of Elastic Field in a Stiffened Cantilever of Laminated Composite

    Directory of Open Access Journals (Sweden)

    N. M. L. Huq

    2012-01-01

    Full Text Available A mathematical model is developed for the analytical solution to elastic filed in a deep stiffened cantilever beam of laminated composite under mixed boundary conditions. The two displacement parameters associated with the two-dimensional elasticity problems are defined in terms of a single displacement potential function such that one of the equilibrium equations is satisfied automatically. This reduces the problem to the solution of a single fourth-order partial differential equation, which is solved in terms of Fourier series. To present some numerical results, cantilever beams of glass/epoxy cross-ply and angle-ply laminated composites are considered and different components of stress and displacement at different sections of the beam are presented. The effects of laminate stacking sequence and ply-angle of the cross-ply and angle-ply composite beams, respectively, on the elastic field are analyzed. The numerical results justify that the present mathematical model is simple whereas capable to generate exact results of elastic field in a cantilever beam even at the critical regions of supports and loadings.

  19. Hydrogen-enhanced cracking revealed by in situ micro-cantilever bending test inside environmental scanning electron microscope

    Science.gov (United States)

    Deng, Yun; Hajilou, Tarlan; Barnoush, Afrooz

    2017-06-01

    To evaluate the hydrogen (H)-induced embrittlement in iron aluminium intermetallics, especially the one with stoichiometric composition of 50 at.% Al, a novel in situ micro-cantilever bending test was applied within an environmental scanning electron microscope (ESEM), which provides both a full process monitoring and a clean, in situ H-charging condition. Two sets of cantilevers were analysed in this work: one set of un-notched cantilevers, and the other set with focused ion beam-milled notch laying on two crystallographic planes: (010) and (110). The cantilevers were tested under two environmental conditions: vacuum (approximately 5 × 10-4 Pa) and ESEM (450 Pa water vapour). Crack initiation at stress-concentrated locations and propagation to cause catastrophic failure were observed when cantilevers were tested in the presence of H; while no cracking occurred when tested in vacuum. Both the bending strength for un-notched beams and the fracture toughness for notched beams were reduced under H exposure. The hydrogen embrittlement (HE) susceptibility was found to be orientation dependent: the (010) crystallographic plane was more fragile to HE than the (110) plane. This article is part of the themed issue 'The challenges of hydrogen and metals'.

  20. Study of sensitivity and noise in the piezoelectric self-sensing and self-actuating cantilever with an integrated Wheatstone bridge circuit.

    Science.gov (United States)

    Shin, ChaeHo; Jeon, InSu; Khim, Zheong G; Hong, J W; Nam, HyoJin

    2010-03-01

    A detection method using a self-sensing cantilever is more desirable than other detection methods (optical fiber and laser beam bounce detection) that are bulky and require alignment. The advantage of the self-sensing cantilever is its simplicity, particularly its simple structure. It can be used for the construction of an atomic force microscopy system with a vacuum, fluids, and a low temperature chamber. Additionally, the self-actuating cantilever can be used for a high speed scanning system because the bandwidth is larger than the bulk scanner. Frequently, ZnO film has been used as an actuator in a self-actuating cantilever. In this paper, we studied the characteristics of the self-sensing and self-actuating cantilever with an integrated Wheatstone bridge circuit substituting the ZnO film with a lead zirconate titanate (PZT) film as the actuator. We can reduce the leakage current (to less than 10(-4) A/cm(2)) in the PZT cantilever and improve sensor sensitivity through a reduction of noise level from the external sensor circuit using the Wheatstone bridge circuit embedded into the cantilever. The self-sensing and actuating cantilever with an integrated Wheatstone bridge circuit was compared with a commercial self-sensing cantilever or self-sensing and actuating cantilever without an integrated Wheatstone bridge circuit. The measurement results have shown that sensing the signal to noise level and the minimum detectable deflection improved to 4.78 mV and 1.18 nm, respectively. We believe that this cantilever allows for easier system integration and miniaturization, provides better controllability and higher scan speeds, and offers the potential for full automation.

  1. Microstructuring of piezoresistive cantilevers for gas detection and analysis

    International Nuclear Information System (INIS)

    Sarov, Y.; Sarova, V.; Bitterlich, Ch.; Richter, O.; Guliyev, E.; Zoellner, J.-P.; Rangelow, I. W.; Andok, R.; Bencurova, A.

    2011-01-01

    In this work we report on a design and fabrication of cantilevers for gas detection and analysis. The cantilevers have expanded area of interaction with the gas, while the signal transduction is realized by an integrated piezoresistive deflection sensor, placed at the narrowed cantilever base with highest stress along the cantilever. Moreover, the cantilevers have integrated bimorph micro-actuator detection in a static and dynamic mode. The cantilevers are feasible as pressure, temperature and flow sensors and under chemical functionalization - for gas recognition, tracing and composition analysis. (authors)

  2. Splitting Descartes

    DEFF Research Database (Denmark)

    Schilhab, Theresa

    2007-01-01

    Kognition og Pædagogik vol. 48:10-18. 2003 Short description : The cognitivistic paradigm and Descartes' view of embodied knowledge. Abstract: That the philosopher Descartes separated the mind from the body is hardly news: He did it so effectively that his name is forever tied to that division....... But what exactly is Descartes' point? How does the Kartesian split hold up to recent biologically based learning theories?...

  3. Modelling of Spring Constant and Pull-down Voltage of Non-uniform RF MEMS Cantilever Incorporating Stress Gradient

    Directory of Open Access Journals (Sweden)

    Shimul Chandra SAHA

    2008-11-01

    Full Text Available We have presented a model for spring constant and pull-down voltage of a non-uniform radio frequency microelectromechanical systems (RF MEMS cantilever that works on electrostatic actuation. The residual stress gradient in the beam material that may arise during the fabrication process is also considered in the model. Using basic force deflection calculation of the suspended beam, a stand-alone model for the spring constant and pull-down voltage of the non-uniform cantilever is developed. To compare the model, simulation is performed using standard Finite Element Method (FEM analysis tolls from CoventorWare. The model matches very well with the FEM simulation results. The model will offer an efficient means of design, analysis, and optimization of RF MEMS cantilever switches.

  4. Application of RF-MEMS-Based Split Ring Resonators (SRRs to the Implementation of Reconfigurable Stopband Filters: A Review

    Directory of Open Access Journals (Sweden)

    Ferran Martín

    2014-12-01

    Full Text Available In this review paper, several strategies for the implementation of reconfigurable split ring resonators (SRRs based on RF-MEMS switches are presented. Essentially three types of RF-MEMS combined with split rings are considered: (i bridge-type RF-MEMS on top of complementary split ring resonators CSRRs; (ii cantilever-type RF-MEMS on top of SRRs; and (iii cantilever-type RF-MEMS integrated with SRRs (or RF-MEMS SRRs. Advantages and limitations of these different configurations from the point of view of their potential applications for reconfigurable stopband filter design are discussed, and several prototype devices are presented.

  5. Application of RF-MEMS-based split ring resonators (SRRs) to the implementation of reconfigurable stopband filters: a review.

    Science.gov (United States)

    Martín, Ferran; Bonache, Jordi

    2014-12-02

    In this review paper, several strategies for the implementation of reconfigurable split ring resonators (SRRs) based on RF-MEMS switches are presented. Essentially three types of RF-MEMS combined with split rings are considered: (i) bridge-type RF-MEMS on top of complementary split ring resonators CSRRs; (ii) cantilever-type RF-MEMS on top of SRRs; and (iii) cantilever-type RF-MEMS integrated with SRRs (or RF-MEMS SRRs). Advantages and limitations of these different configurations from the point of view of their potential applications for reconfigurable stopband filter design are discussed, and several prototype devices are presented.

  6. Design & fabrication of cantilever array biosensors

    DEFF Research Database (Denmark)

    Boisen, Anja; Thundat, T

    2009-01-01

    Surface immobilization of functional receptors on microfabricated cantilever arrays offers a new paradigm for the development of biosensors based on nanomechanics. Microcantilever-based systems are capable of real-time, multiplexed detection of unlabeled disease markers in extremely small volumes......, electronic processing, and even local telemetry on a single chip have the potential of satisfying the need for highly sensitive and selective multiple-target detection in very small samples. Here we will review the design and fabrication process of cantilever-based biosensors....

  7. Electronically droplet energy harvesting using piezoelectric cantilevers

    KAUST Repository

    Al Ahmad, Mahmoud Al

    2012-01-01

    A report is presented on free falling droplet energy harvesting using piezoelectric cantilevers. The harvester incorporates a multimorph clamped-free cantilever which is composed of five layers of lead zirconate titanate piezoelectric thick films. During the impact, the droplet kinetic energy is transferred into the form of mechanical stress forcing the piezoelectric structure to vibrate. Experimental results show energy of 0.3 μJ per droplet. The scenario of moderate falling drop intensity, i.e. 230 drops per second, yields a total energy of 400 μJ. © 2012 The Institution of Engineering and Technology.

  8. Physics-based signal processing algorithms for micromachined cantilever arrays

    Science.gov (United States)

    Candy, James V; Clague, David S; Lee, Christopher L; Rudd, Robert E; Burnham, Alan K; Tringe, Joseph W

    2013-11-19

    A method of using physics-based signal processing algorithms for micromachined cantilever arrays. The methods utilize deflection of a micromachined cantilever that represents the chemical, biological, or physical element being detected. One embodiment of the method comprises the steps of modeling the deflection of the micromachined cantilever producing a deflection model, sensing the deflection of the micromachined cantilever and producing a signal representing the deflection, and comparing the signal representing the deflection with the deflection model.

  9. Polymeric cantilever-based biosensors with integrated readout

    DEFF Research Database (Denmark)

    Johansson, Alicia; Blagoi, Gabriela; Boisen, Anja

    2006-01-01

    The authors present an SU-8 cantilever chip with integrated piezoresistors for detection of surface stress changes due to adsorption of biomolecules on the cantilever surface. Mercaptohexanol is used as a model biomolecule to study molecular interactions with Au-coated SU-8 cantilevers and surfac...

  10. Cantilever-Based Microwave Biosensors: Analysis, Designs and Optimizations

    DEFF Research Database (Denmark)

    Jiang, Chenhui; Johansen, Tom Keinicke; Jónasson, Sævar Þór

    2011-01-01

    This paper presents a novel microwave readout scheme for measuring deflection of cantilevers in nanometer range. The cantilever deflection can be sensed by the variation of transmission levels or resonant frequencies of microwave signals. The sensitivity of the cantilever biosensor based on LC...

  11. Characterization of piesoelectric ZnO thin films and the fabrication of piezoelectric micro-cantilevers

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Raegan Lynn [Iowa State Univ., Ames, IA (United States)

    2005-01-01

    In Atomic Force Microscopy (AFM), a microcantilever is raster scanned across the surface of a sample in order to obtain a topographical image of the sample's surface. In a traditional, optical AFM, the sample rests on a bulk piezoelectric tube and a control loop is used to control the tip-sample separation by actuating the piezo-tube. This method has several disadvantages--the most noticeable one being that response time of the piezo-tube is rather long which leads to slow imaging speeds. One possible solution aimed at improving the speed of imaging is to incorporate a thin piezoelectric film on top of the cantilever beam. This design not only improves the speed of imaging because the piezoelectric film replaces the piezo-tube as an actuator, but the film can also act as a sensor. In addition, the piezoelectric film can excite the cantilever beam near its resonance frequency. This project aims to fabricate piezoelectric microcantilevers for use in the AFM. Prior to fabricating the cantilevers and also part of this project, a systematic study was performed to examine the effects of deposition conditions on the quality of piezoelectric ZnO thin films deposited by RF sputtering. These results will be presented. The deposition parameters that produced the highest quality ZnO film were used in the fabrication of the piezoelectric cantilevers. Unfortunately, the fabricated cantilevers warped due to the intrinsic stress of the ZnO film and were therefore not usable in the AFM. The complete fabrication process will be detailed, the results will be discussed and reasons for the warping will be examined.

  12. Operating characteristics of a cantilever-mounted resilient-pad gas-lubricated thrust bearing

    Science.gov (United States)

    Nemeth, Z. N.

    1979-01-01

    A resilient-pad gas thrust bearing consisting of pads mounted on cantilever beams was tested to determine its operating characteristic. The bearing was run at a thrust load of 74 newtons to a speed of 17000 rpm. The pad film thickness and bearing friction torque were measured and compared with theory. The measured film thickness was less than that predicted by theory. The bearing friction torque was greater than that predicted by theory.

  13. Analysis and design of a cantilever-mounted resilient-pad gas-lubricated thrust bearing

    Science.gov (United States)

    Etsion, I.

    1976-01-01

    A thrust bearing consisting of pads mounted on resilient, metallic, cantilever beams is described and analyzed. Compliance and stiffness of the bearing assembly are discussed, and the effects of bearing design parameters on performance are shown. After the general analysis, a design example is presented for a flat sector-shaped gas bearing. A special case where zero axial movement of the runner can be obtained is pointed out.

  14. Solar-hydrogen energy systems: an authoritative review of water-splitting systems by solar beam and solar heat : hydrogen production, storage, and utilisation

    National Research Council Canada - National Science Library

    Ōta, Tokio

    1979-01-01

    ... An Authoritative Review of Watersplitting Systems by Solar Beam and Solar Heat: Hydrogen Production, Storage and Utilisation edited by TOKIO OHTA Professor of Materials Science and Energy System Yoko...

  15. In vitro evaluation of failure loads of nonmetal cantilevered resin-bonded fixed dental prostheses.

    Science.gov (United States)

    van Dalen, Andy; Feilzer, Albert J; Kleverlaan, Cornelis J

    2008-12-01

    To evaluate in vitro the influence of fiber reinforcement on the failure loads of resin composite beams, simulating cantilevered two-unit resin-bonded fixed dental prostheses, and compare the results with similarly obtained failure loads of ZrO2 and CoCr beams of a comparable design. Peel tests were performed using resin composite, fiber-reinforced resin composite, and zirconia beams, simulating two-unit cantilevered resin-bonded fixed dental prostheses, luted with Panavia F2.0 onto flat-ground buccal surfaces of bovine mandibular incisors. The recorded failure loads were compared with those of CoCr beams of a similar size and design from earlier research. Finite element analysis revealed the stress concentrations within the cement layers at failure. The failure loads (N) of the peel tests, depending on the beam type and including the type of failure, were statistically analyzed. The highest failure values were obtained with the fiber-reinforced resin composite beams, which were luted with the exposed fibers directly on the bovine enamel. Finite element analysis showed that peak stress locations depend on the beam type and facilitate the explanation of the different failure modes. Fiber-reinforcement of simulated two-unit cantilevered resin composite resin-bonded fixed dental prostheses does not necessarily lead to higher failure loads. This study identified significant differences in peel failure loads between identical specimens, depending on whether or not the fiber reinforcement was exposed on the luting surface. Further research needs to be carried out regarding the combination of resin composite and fiber reinforcement.

  16. Peculiarities of the Third Natural Frequency Vibrations of a Cantilever for the Improvement of Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Vytautas Ostasevicius

    2015-05-01

    Full Text Available This paper focuses on several aspects extending the dynamical efficiency of a cantilever beam vibrating in the third mode. A few ways of producing this mode stimulation, namely vibro-impact or forced excitation, as well as its application for energy harvesting devices are proposed. The paper presents numerical and experimental analyses of novel structural dynamics effects along with an optimal configuration of the cantilever beam. The peculiarities of a cantilever beam vibrating in the third mode are related to the significant increase of the level of deformations capable of extracting significant additional amounts of energy compared to the conventional harvester vibrating in the first mode. Two types of a piezoelectric vibrating energy harvester (PVEH prototype are analysed in this paper: the first one without electrode segmentation, while the second is segmented using electrode segmentation at the strain nodes of the third vibration mode to achieve effective operation at the third resonant frequency. The results of this research revealed that the voltage generated by any segment of the segmented PVEH prototype excited at the third resonant frequency demonstrated a 3.4–4.8-fold increase in comparison with the non-segmented prototype. Simultaneously, the efficiency of the energy harvester prototype also increased at lower resonant frequencies from 16% to 90%. The insights presented in the paper may serve for the development and fabrication of advanced piezoelectric energy harvesters which would be able to generate a considerably increased amount of electrical energy independently of the frequency of kinematical excitation.

  17. From MEMS to NEMS : Scaling Cantilever Sensors

    NARCIS (Netherlands)

    Yang, C.K.

    2012-01-01

    This thesis studies the effects of scaling on the characterisation and readout of micro-electro mechanical systems (MEMS) to nano-electro mechanical systems (NEMS). In particular it focuses on cantilever, which is a basic device building block and an important transducer in many sensing

  18. Bullet Design of MEMS Cantilever - Hand Calculation

    Directory of Open Access Journals (Sweden)

    Abhijeet V. KSHIRSAGAR

    2008-04-01

    Full Text Available The present article describes the basic hand calculations for design of MEMS cantilever for beginners. The MATLAB software code was written to analysis the all formulae. Further the article gives insight of important parameters, its dependence and consideration for a good design.

  19. Dynamic Characterization of Silicon Nitride Cantilevers

    NARCIS (Netherlands)

    Babaei Gavan, K.

    2009-01-01

    This thesis describes a series of experiments on dynamical characterization of silicon nitride cantilevers. These devices play an important role in micro-and nanoelectromechanical systems (MEMS and NEMS). They consist of a mechanical part, a sensor or actuator, and an electronic part for readout and

  20. Calibration of higher eigenmodes of cantilevers

    Energy Technology Data Exchange (ETDEWEB)

    Labuda, Aleksander; Kocun, Marta; Walsh, Tim; Meinhold, Jieh; Proksch, Tania; Meinhold, Waiman; Anderson, Caleb; Proksch, Roger [Asylum Research, an Oxford Instruments Company, Santa Barbara, California 93117 (United States); Lysy, Martin [Department of Statistics and Actuarial Science, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)

    2016-07-15

    A method is presented for calibrating the higher eigenmodes (resonant modes) of atomic force microscopy cantilevers that can be performed prior to any tip-sample interaction. The method leverages recent efforts in accurately calibrating the first eigenmode by providing the higher-mode stiffness as a ratio to the first mode stiffness. A one-time calibration routine must be performed for every cantilever type to determine a power-law relationship between stiffness and frequency, which is then stored for future use on similar cantilevers. Then, future calibrations only require a measurement of the ratio of resonant frequencies and the stiffness of the first mode. This method is verified through stiffness measurements using three independent approaches: interferometric measurement, AC approach-curve calibration, and finite element analysis simulation. Power-law values for calibrating higher-mode stiffnesses are reported for several cantilever models. Once the higher-mode stiffnesses are known, the amplitude of each mode can also be calibrated from the thermal spectrum by application of the equipartition theorem.

  1. Calibration of higher eigenmodes of cantilevers

    International Nuclear Information System (INIS)

    Labuda, Aleksander; Kocun, Marta; Walsh, Tim; Meinhold, Jieh; Proksch, Tania; Meinhold, Waiman; Anderson, Caleb; Proksch, Roger; Lysy, Martin

    2016-01-01

    A method is presented for calibrating the higher eigenmodes (resonant modes) of atomic force microscopy cantilevers that can be performed prior to any tip-sample interaction. The method leverages recent efforts in accurately calibrating the first eigenmode by providing the higher-mode stiffness as a ratio to the first mode stiffness. A one-time calibration routine must be performed for every cantilever type to determine a power-law relationship between stiffness and frequency, which is then stored for future use on similar cantilevers. Then, future calibrations only require a measurement of the ratio of resonant frequencies and the stiffness of the first mode. This method is verified through stiffness measurements using three independent approaches: interferometric measurement, AC approach-curve calibration, and finite element analysis simulation. Power-law values for calibrating higher-mode stiffnesses are reported for several cantilever models. Once the higher-mode stiffnesses are known, the amplitude of each mode can also be calibrated from the thermal spectrum by application of the equipartition theorem.

  2. An analytic model for accurate spring constant calibration of rectangular atomic force microscope cantilevers.

    Science.gov (United States)

    Li, Rui; Ye, Hongfei; Zhang, Weisheng; Ma, Guojun; Su, Yewang

    2015-10-29

    Spring constant calibration of the atomic force microscope (AFM) cantilever is of fundamental importance for quantifying the force between the AFM cantilever tip and the sample. The calibration within the framework of thin plate theory undoubtedly has a higher accuracy and broader scope than that within the well-established beam theory. However, thin plate theory-based accurate analytic determination of the constant has been perceived as an extremely difficult issue. In this paper, we implement the thin plate theory-based analytic modeling for the static behavior of rectangular AFM cantilevers, which reveals that the three-dimensional effect and Poisson effect play important roles in accurate determination of the spring constants. A quantitative scaling law is found that the normalized spring constant depends only on the Poisson's ratio, normalized dimension and normalized load coordinate. Both the literature and our refined finite element model validate the present results. The developed model is expected to serve as the benchmark for accurate calibration of rectangular AFM cantilevers.

  3. Development of a microfabricated electrochemical-cantilever hybrid platform

    DEFF Research Database (Denmark)

    Fischer, Lee MacKenzie; Pedersen, Christoffer; Elkjær, Karl

    2011-01-01

    The design and fabrication of a combined electrochemical-cantilever microfluidic system is described. A chip integrating cantilevers with electrodes into a microchannel is presented with the accompanying polymer flow cell. Issues such as electrical and fluid connections are addressed......, electromechanical behavior in ionic solution is investigated, and two uses of the system are demonstrated. First, all cantilevers are functionalized with cysteine, to facilitate detection of Cu2+ ions, then one cantilever is electrochemically cleaned in situ to generate a reference cantilever for differential...

  4. On symmetric X-ray beam splitting with high efficiency by use of reflection gratings with rectangular profile in the extreme off-plane configuration.

    Science.gov (United States)

    Jark, Werner; Eichert, Diane

    2015-08-24

    In order to be reflected or diffracted off a surface structure soft X-rays and hard X-rays need to impinge at grazing angles of incidence onto the surface. In case of a reflection grating of highly symmetric structure with rectangular groove profile these grooves can be oriented parallel to the beam trajectory. In such a symmetric situation the distribution of the diffracted intensity with respect to the plane of incidence is then expected to be symmetric. This is indeed observed with symmetrically oriented diffraction peaks. It can be predicted that for appropriate structure parameters the intensity can be contained mostly in two symmetrically oriented diffraction peaks. This will also be the case for hard X-rays. The diffraction efficiency will be particularly high, when the angle of grazing incidence is chosen in the total reflection regime below the critical angle of the grating coating. These predictions were experimentally verified in this work for hard X-rays with photon energies between 4 keV and 12.4 keV. In the experiment of the order of 30% of the incident intensity was diffracted into the two first orders. This is to be compared to reflectivities of the order of 50% measured at the same coating in an unruled area of the substrate. Consequently the relative structural diffraction efficiency for each first order was about 30%, while ideally it could have been 40%. The presented grating structure will thus be a rather efficient amplitude beam splitter for hard X-rays, e.g. in the coherent beam from a free electron laser. In addition such object could then be used as the first component in Michelson interferometers for the beam characterisation or for introducing a time delay between two coherent beams.

  5. An experimentally validated bimorph cantilever model for piezoelectric energy harvesting from base excitations

    International Nuclear Information System (INIS)

    Erturk, A; Inman, D J

    2009-01-01

    Piezoelectric transduction has received great attention for vibration-to-electric energy conversion over the last five years. A typical piezoelectric energy harvester is a unimorph or a bimorph cantilever located on a vibrating host structure, to generate electrical energy from base excitations. Several authors have investigated modeling of cantilevered piezoelectric energy harvesters under base excitation. The existing mathematical modeling approaches range from elementary single-degree-of-freedom models to approximate distributed parameter solutions in the sense of Rayleigh–Ritz discretization as well as analytical solution attempts with certain simplifications. Recently, the authors have presented the closed-form analytical solution for a unimorph cantilever under base excitation based on the Euler–Bernoulli beam assumptions. In this paper, the analytical solution is applied to bimorph cantilever configurations with series and parallel connections of piezoceramic layers. The base excitation is assumed to be translation in the transverse direction with a superimposed small rotation. The closed-form steady state response expressions are obtained for harmonic excitations at arbitrary frequencies, which are then reduced to simple but accurate single-mode expressions for modal excitations. The electromechanical frequency response functions (FRFs) that relate the voltage output and vibration response to translational and rotational base accelerations are identified from the multi-mode and single-mode solutions. Experimental validation of the single-mode coupled voltage output and vibration response expressions is presented for a bimorph cantilever with a tip mass. It is observed that the closed-form single-mode FRFs obtained from the analytical solution can successfully predict the coupled system dynamics for a wide range of electrical load resistance. The performance of the bimorph device is analyzed extensively for the short circuit and open circuit resonance

  6. Calibration of optical cantilever deflection readers

    International Nuclear Information System (INIS)

    Hu Zhiyu; Seeley, Tim; Kossek, Sebastian; Thundat, Thomas

    2004-01-01

    Because of its ultrahigh sensitivity, the optical lever detection method similar to that used in the atomic force microscope (AFM) has been widely employed as a standard technique for measuring microcantilever deflection. Along with the increasing interest in using the microcantilever as a sensing platform, there is also a requirement for a reliable calibration technique. Many researchers have used the concept of optical lever detection to construct microcantilever deflection readout instruments for chemical, physical, and biological detection. However, without an AFM piezo z scanner, it is very difficult to precisely calibrate these instruments. Here, we present a step-by-step method to conveniently calibrate an instrument using commercially available piezoresistive cantilevers. The experimental results closely match the theoretical calculation. Following this procedure, one can easily calibrate any optical cantilever deflection detection system with high reproducibility, precision, and reliability. A detailed discussion of the optical lever readout system design has been addressed in this article

  7. Vortex Anemometer Using MEMS Cantilever Sensor

    CERN Document Server

    Zylka, P; Zylka, Pawel; Modrzynski, Pawel

    2010-01-01

    This paper presents construction and performance of a novel hybrid microelectromechanical system (MEMS) vortex flowmeter. A miniature cantilever MEMS displacement sensor was used to detect frequency of vortices development. 3-mm-long silicon cantilever, protruding directly out of a trailing edge of a trapezoidal glass-epoxy composite bluff body was put into oscillatory motion by vortices shed alternately from side surfaces of the obstacle. Verified linearmeasurement range of the device extended from 5 to 22 m/s; however, it could be broadened in absence of external 50-Hz mains electrical interfering signal which required bandpass frequency-domain digital sensor signal processing. The MEMS vortex sensor proved its effectiveness in detection of semilaminar airflow velocity distribution in a 40-mm-diameter tubular pipe.

  8. Cantilever steel post damaged by wind

    Directory of Open Access Journals (Sweden)

    Wei Sha

    2014-10-01

    Full Text Available An analysis for the cause of fracture failure of a cantilever steel sign post damaged by wind has been carried out. An unusual cause of failure has been identified, which is the subject of this paper. Microscopy and microanalysis of the fracture surface showed that the failure was due to pre-existing cracks, from the fabrication of the post. This conclusion was reached after detecting and analysing a galvanised layer on the fracture surfaces.

  9. Dynamic properties of magneto-sensitive elastomer cantilevers as adaptive sensor elements

    Science.gov (United States)

    Becker, T. I.; Raikher, Yu L.; Stolbov, O. V.; Böhm, V.; Zimmermann, K.

    2017-09-01

    In engineering applications, one of the actual scientific challenges is a development of sensor systems with complex adaptive behaviour and operating sensitivity. Smart materials like magneto-sensitive elastomers (MSEs) offer great potential for designing such intelligent devices, because they possess unique magnetic-field dependent properties. This paper deals with the investigation of the free vibrational behaviour displayed by cantilever beams made of MSEs containing magnetically soft particles in the presence of a uniform magnetic field. The presented setup is considered as a prototype of a sensitive unit for transforming mechanical stimuli of the base into vibrations of the MSE element, which could be converted in a facile way into electromagnetic signals for measuring and analysing. It is shown experimentally that for the MSE beams of several different lengths and compositions, the first eigenfrequency depends strongly on the strength of the applied magnetic field. The developed theoretical model extends the conventional vibrational dynamics of thin rods to allow for the ponderomotive torque induced by magneto-mechanical interactions experienced by an MSE beam. The model has two adjustable parameters that characterise the geometric configuration of the cantilever beam and its magnetic material properties. It is found that the values of these parameters are ‘universally’ valid, i.e., they provide good agreement between the theoretical eigenfrequency dependencies and the experimental results for all used MSE beams. The evidence presented ensures a good basis for further investigations of the sensitivity and amplitude-frequency characteristics of MSE vibration sensor elements.

  10. Dynamic state switching in nonlinear multiferroic cantilevers

    Science.gov (United States)

    Wang, Yi; Onuta, Tiberiu-Dan; Long, Christian J.; Lofland, Samuel E.; Takeuchi, Ichiro

    2013-03-01

    We demonstrate read-write-read-erase cyclical mechanical-memory properties of all-thin-film multiferroic heterostructured Pb(Zr0.52Ti0.48) O3 / Fe0.7Ga0.3 cantilevers when a high enough voltage around the resonant frequency of the device is applied on the Pb(Zr0.52Ti0.48) O3 piezo-film. The device state switching process occurs due to the presence of a hysteresis loop in the piezo-film frequency response, which comes from the nonlinear behavior of the cantilever. The reference frequency at which the strain-mediated Fe0.7Ga0.3 based multiferroic device switches can also be tuned by applying a DC magnetic field bias that contributes to the increase of the cantilever effective stiffness. The switching dynamics is mapped in the phase space of the device measured transfer function characteristic for such high piezo-film voltage excitation, providing additional information on the dynamical stability of the devices.

  11. The output characteristic of cantilever-like tactile sensor based on the inverse magnetostrictive effect

    Directory of Open Access Journals (Sweden)

    Lili Wan

    2017-05-01

    Full Text Available The output characteristic model of a magnetostrictive cantilever-like tactile sensor has been founded based on the inverse-magnetostrictive effect, the flexure mode, and the Jiles-Atherton model. The magnetostrictive sensor has been designed and an output voltage is analyzed under the conditions of bias magnetic field, contact pressure and deflection of cantilever beam. The experiment has been performed to determine the relation among the induced output voltage, bias magnetic field, and pressure. It is found that the peak of the induced output voltage increases with an increasing pressure under the bias magnetic field of 4.8kA/m. The experimental result agrees well with the theoretical one and it means that the model can describe the relation among the induced output voltage, bias magnetic field, and pressure. The sensor with a Galfenol sheet may hold potentials in sample characterization and deformation predication in artificial intelligence area.

  12. Experimental characterization of cantilever-type piezoelectric generator operating at resonance for vibration energy harvesting

    Energy Technology Data Exchange (ETDEWEB)

    Montanini, Roberto, E-mail: rmontanini@unime.it; Quattrocchi, Antonino, E-mail: aquattrocchi@unime.it [University of Messina, Dept. of Engineering, Contrada di Dio, Messina (Italy)

    2016-06-28

    A cantilever-type resonant piezoelectric generator (RPG) has been designed by gluing a PZT patch working in d{sub 31} mode onto a glass fibre reinforced composite cantilever beam with a discrete mass applied on its free end. The electrical and dynamic behaviour of the RPG prototype has been investigated by carrying out laboratory tests aimed to assess the effect of definite design parameters, specifically the electric resistance load and the excitation frequency. Results showed that an optimum resistance load exists, at which power generation is maximized. Moreover, it has been showed that power generation is strongly influenced by the vibration frequency highlighting that, at resonance, output power can be increased by more than one order of magnitude. Possible applications include inertial resonant harvester for energy recovery from vibrating machines, sea waves or wind flux and self-powering of wireless sensor nodes.

  13. Experimental characterization of cantilever-type piezoelectric generator operating at resonance for vibration energy harvesting

    Science.gov (United States)

    Montanini, Roberto; Quattrocchi, Antonino

    2016-06-01

    A cantilever-type resonant piezoelectric generator (RPG) has been designed by gluing a PZT patch working in d31 mode onto a glass fibre reinforced composite cantilever beam with a discrete mass applied on its free end. The electrical and dynamic behaviour of the RPG prototype has been investigated by carrying out laboratory tests aimed to assess the effect of definite design parameters, specifically the electric resistance load and the excitation frequency. Results showed that an optimum resistance load exists, at which power generation is maximized. Moreover, it has been showed that power generation is strongly influenced by the vibration frequency highlighting that, at resonance, output power can be increased by more than one order of magnitude. Possible applications include inertial resonant harvester for energy recovery from vibrating machines, sea waves or wind flux and self-powering of wireless sensor nodes.

  14. Nonlinear mathematical modeling of vibrating motion of nanomechanical cantilever active probe

    Directory of Open Access Journals (Sweden)

    Reza Ghaderi

    Full Text Available Nonlinear vibration response of nanomechanical cantilever (NMC active probes in atomic force microscope (AFM application has been studied in the amplitude mode. Piezoelectric layer is placed piecewise and as an actuator on NMC. Continuous beam model has been chosen for analysis with regard to the geometric discontinuities of piezoelectric layer attachment and NMC's cross section. The force between the tip and the sample surface is modeled using Leonard-Jones potential. Assuming that cantilever is inclined to the sample surface, the effect of nonlinear force on NMC is considered as a shearing force and the concentrated bending moment is regarded at the end. Nonlinear frequency response of NMC is obtained close to the sample surface using the dynamic modeling. It is then become clear that the distance and angle of NMC, the probe length, and the geometric dimensions of piezoelectric layer can affect frequency response bending of the curve.

  15. Emittance compensation in split photoinjectors

    Directory of Open Access Journals (Sweden)

    Klaus Floettmann

    2017-01-01

    Full Text Available The compensation of correlated emittance contributions is of primary importance to optimize the performance of high brightness photoinjectors. While only extended numerical simulations can capture the complex beam dynamics of space-charge-dominated beams in sufficient detail to optimize a specific injector layout, simplified models are required to gain a deeper understanding of the involved dynamics, to guide the optimization procedure, and to interpret experimental results. In this paper, a slice envelope model for the emittance compensation process in a split photoinjector is presented. The emittance term is included in the analytical solution of the beam envelope in a drift, which is essential to take the emittance contribution due to a beam size mismatch into account. The appearance of two emittance minima in the drift is explained, and the matching into the booster cavity is discussed. A comparison with simulation results points out effects which are not treated in the envelope model, such as overfocusing and field nonlinearities.

  16. Evaluation of the accuracy of linear measurements on multi-slice and cone beam computed tomography scans to detect the mandibular canal during bilateral sagittal split osteotomy of the mandible.

    Science.gov (United States)

    Freire-Maia, B; Machado, V deC; Valerio, C S; Custódio, A L N; Manzi, F R; Junqueira, J L C

    2017-03-01

    The aim of this study was to compare the accuracy of linear measurements of the distance between the mandibular cortical bone and the mandibular canal using 64-detector multi-slice computed tomography (MSCT) and cone beam computed tomography (CBCT). It was sought to evaluate the reliability of these examinations in detecting the mandibular canal for use in bilateral sagittal split osteotomy (BSSO) planning. Eight dry human mandibles were studied. Three sites, corresponding to the lingula, the angle, and the body of the mandible, were selected. After the CT scans had been obtained, the mandibles were sectioned and the bone segments measured to obtain the actual measurements. On analysis, no statistically significant difference was found between the measurements obtained through MSCT and CBCT, or when comparing the measurements from these scans with the actual measurements. It is concluded that the images obtained by CT scan, both 64-detector multi-slice and cone beam, can be used to obtain accurate linear measurements to locate the mandibular canal for preoperative planning of BSSO. The ability to correctly locate the mandibular canal during BSSO will reduce the occurrence of neurosensory disturbances in the postoperative period. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  17. Free vibration and reliability of composite cantilevers featuring uncertain properties

    International Nuclear Information System (INIS)

    Oh, D.H.; Librescu, L.

    1997-01-01

    The problem of free vibration and reliability of cantilever composite beams featuring structural uncertainties is analyzed. The random structural uncertainties involve material properties, thickness and fiber orientation of the individual constituent laminae. Such uncertainties undoubtedly affect the achievable performance as well as their structural reliabilities. In order to investigate the effects of random structural uncertainties on free vibration problem, a stochastic eigenvalue problem of self-adjoint systems is formulated to provide first and second moments of eigenvalues, i.e., their mean and variance. In this context, a stochastic finite element method based on the mean-centered-second-moment method and first-order perturbation technique are employed during the probabilistic discretization of uncertain distributed-parameter structural systems. Sensitivity and reliability analyses for the uncertain beam when subjected to an external oscillatory load are performed. In addition, in order to mitigate the detrimental effects of uncertainties and so, to render the structure more robust to such effects, the structural tailoring technique is implemented and its beneficial effects are revealed

  18. Understanding interferometry for micro-cantilever displacement detection

    Directory of Open Access Journals (Sweden)

    Alexander von Schmidsfeld

    2016-06-01

    Full Text Available Interferometric displacement detection in a cantilever-based non-contact atomic force microscope (NC-AFM operated in ultra-high vacuum is demonstrated for the Michelson and Fabry–Pérot modes of operation. Each mode is addressed by appropriately adjusting the distance between the fiber end delivering and collecting light and a highly reflective micro-cantilever, both together forming the interferometric cavity. For a precise measurement of the cantilever displacement, the relative positioning of fiber and cantilever is of critical importance. We describe a systematic approach for accurate alignment as well as the implications of deficient fiber–cantilever configurations. In the Fabry–Pérot regime, the displacement noise spectral density strongly decreases with decreasing distance between the fiber-end and the cantilever, yielding a noise floor of 24 fm/Hz0.5 under optimum conditions.

  19. Micro‑cantilevers for optical sensing of biogenic amines

    DEFF Research Database (Denmark)

    Wang, Ying; Bravo Costa, Carlos André; Sobolewska, Elżbieta Karolina

    2017-01-01

    molecules in the gas phase. Different functionalization conditions were investigated by immersing gold coated AFM cantilevers in cyclam solutions at different concentrations, for different functionalization times, and for different post-annealing treatments. The optimum morphology for high capture...... micro-cantilever based mass detection. We demonstrate that besides conventional AFM systems a MEMS cantilever in combination with an optical read out is a powerful analytic system which is highly attractive for widespread use in diagnostic applications, with optimized functionalization conditions...

  20. Force sensors based on screen-printed cantilevers

    OpenAIRE

    Lakhmi, Riadh; Debéda, Hélène; Dufour, Isabelle; Lucat, Claude

    2010-01-01

    International audience; In this paper, the design, the fabrication and the characterization of ceramic screen-printed force sensors aredescribed. They are based on the use of cantilevers with integrated piezoresistors. The choice of the materials constitutingthe cantilever and the strain gauge, so as the dimensions of the cantilever have been optimized in order to measure forces in mNrange. The sensors have been fabricated using the screenprinting technique associated with the sacrificial lay...

  1. Towards a precise measurement of the antihydrogen ground state hyperfine splitting in a beam: the case of in-flight radiative decays

    Science.gov (United States)

    Lundmark, R.; Malbrunot, C.; Nagata, Y.; Radics, B.; Sauerzopf, C.; Widmann, E.

    2015-09-01

    The ASACUSA antihydrogen setup at the CERN Antiproton Decelerator (AD) consists of an antihydrogen source (cusp magnet coupled to a positron source and an antiproton catching magnet) followed by a spectrometer beamline. After production in the cusp, the antihydrogen atoms decay while they escape the trap leading to changes in their effective magnetic moment which in turn affect their trajectories in the beamline. Those sequential decays in the presence of a varying magnetic field strength from their production point in the cusp to their detection at the end of the spectrometer line can in principle greatly affect the prospects for a precision measurement of the antihydrogen hyperfine splitting given the so-far relatively low number of available anti-atoms. The impact of the antihydrogen decay in this context has for the first time been simulated. The implementation of atomic radiative decay has been done in Geant4 to extend the particle tracking capabilities originally embedded in Geant4 to excited atoms, and to allow studies of the effect of dynamic atomic properties on trajectories. This new tool thus allows the study of particle-matter interaction via the Geant4 toolkit while properly taking into account the atomic nature of the object under study. The implementation as well as impacts on the experimental sensitivity for antihydrogen spectroscopy are discussed in this paper.

  2. Modelling Convergence of Finite Element Analysis of Cantilever Beam

    African Journals Online (AJOL)

    Convergence studies are carried out by investigating the convergence of numerical results as the number of elements is increased. If convergence is not obtained, the engineer using the finite element method has absolutely no indication whether the results are indicative of a meaningful approximation to the correct solution ...

  3. Comparison of Wood Composite Properties Using Cantilever-Beam Bending

    Science.gov (United States)

    Houjiang Zhang; John F. Hunt; Lujing Zhou

    2015-01-01

    Wood-based composite panels generally are first tested out-of-plane in the primarypanel directionfollowed by the cross panel direction, but rarely edgewise. While most applications use wood-based composites in the flat-wise orientation and only need the out-of-plane properties, there are construction configurations where edgewise properties are needed for improved...

  4. Lorentz force actuation of a heated atomic force microscope cantilever.

    Science.gov (United States)

    Lee, Byeonghee; Prater, Craig B; King, William P

    2012-02-10

    We report Lorentz force-induced actuation of a silicon microcantilever having an integrated resistive heater. Oscillating current through the cantilever interacts with the magnetic field around a NdFeB permanent magnet and induces a Lorentz force that deflects the cantilever. The same current induces cantilever heating. With AC currents as low as 0.2 mA, the cantilever can be oscillated as much as 80 nm at resonance with a DC temperature rise of less than 5 °C. By comparison, the AC temperature variation leads to a thermomechanical oscillation that is about 1000 times smaller than the Lorentz deflection at the cantilever resonance. The cantilever position in the nonuniform magnetic field affects the Lorentz force-induced deflection, with the magnetic field parallel to the cantilever having the largest effect on cantilever actuation. We demonstrate how the cantilever actuation can be used for imaging, and for measuring the local material softening temperature by sensing the contact resonance shift.

  5. Theoretical study and design of a splitting-recombining style homogenizer

    International Nuclear Information System (INIS)

    Park, Seong Hee; Ko, Do Kyeong; Kim, Hyun Su; Lim, Gwon; Cha, Byeong Hun; Kim, Cheol Jung

    2001-01-01

    For a flat-top laser beam with low low divergence, new scheme based on splitting, inverting, and recombining has been developed. The previous system developed in MicroLas for multimode Excimer lasers, however, cannot apply to a Gaussian beam. By adding functions of path compensation and adjustable beam overlapping, a new splitting-recombining style homogenizer can convert a Gaussian beam to a flat-top beam. Since this scheme is sensitive to accuracy of separation, ratio of beam splitting, and timing of recombination, input laser beam should be collimated to large size and a beam splitter with dielectric coating should be fabricated with high accuracy. We design and study theoretically the new splitting-recombining style homogenizer for a Gaussian laser beam, including the tolerance caused by misalignment or coating quality, the beam quality depending on the beam overlapping ratio, and the effects of longitudinal pulse profile and time delay between transmitted and re-combined beam.

  6. Nanoscale microwave microscopy using shielded cantilever probes

    KAUST Repository

    Lai, Keji

    2011-04-21

    Quantitative dielectric and conductivity mapping in the nanoscale is highly desirable for many research disciplines, but difficult to achieve through conventional transport or established microscopy techniques. Taking advantage of the micro-fabrication technology, we have developed cantilever-based near-field microwave probes with shielded structures. Sensitive microwave electronics and finite-element analysis modeling are also utilized for quantitative electrical imaging. The system is fully compatible with atomic force microscope platforms for convenient operation and easy integration of other modes and functions. The microscope is ideal for interdisciplinary research, with demonstrated examples in nano electronics, physics, material science, and biology.

  7. Fabrication of biopolymer cantilevers using nanoimprint lithography

    DEFF Research Database (Denmark)

    Keller, Stephan Sylvest; Feidenhans'l, Nikolaj Agentoft; Fisker-Bødker, Nis

    2011-01-01

    The biodegradable polymer poly(l-lactide) (PLLA) was introduced for the fabrication of micromechanical devices. For this purpose, thin biopolymer films with thickness around 10 μm were spin-coated on silicon substrates. Patterning of microcantilevers is achieved by nanoimprint lithography. A major...... challenge was the high adhesion between PLLA and silicon stamp. Optimized stamp fabrication and the deposition of a 125 nm thick fluorocarbon anti-stiction coating on the PLLA allowed the fabrication of biopolymer cantilevers. Resonance frequency measurements were used to estimate the Young’s modulus...

  8. Cantilever surface stress sensors with single-crystalline silicon piezoresistors

    DEFF Research Database (Denmark)

    Rasmussen, Peter Andreas; Hansen, Ole; Boisen, Anja

    2005-01-01

    on cantilever sensors with integrated piezoresistive readout, that one finds between typical atomic force microscopy measurements and the surface stress sensors used in, e.g., biochemical measurements. We have simulated the response from piezoresistive cantilevers as a function of resistor type and placement...

  9. Development of Electrochemical Cantilever Sensors for DNA Applications

    DEFF Research Database (Denmark)

    Quan, Xueling; Heiskanen, Arto; Yi, Sun

    2013-01-01

    In this work, we develop a generic DNA based sensing platform used for characterizing surface functionalization and detecting DNA hybridization. Silicon nitride cantilever sensors are fabricated with an integrated three-electrode system and integrated in a microfluidic chip. Cantilevers with gold...

  10. Interlaboratory round robin on cantilever calibration for AFM force spectroscopy.

    NARCIS (Netherlands)

    Riet, J. te; Katan, A.J.; Rankl, C.; Stahl, S.W.; Buul, A.M. van; Phang, I.Y.; Gomez-Casado, A.; Schon, P.; Gerritsen, J.W.; Cambi, A.; Rowan, A.E.; Vancso, G.J.; Jonkheijm, P.; Huskens, J.; Oosterkamp, T.H.; Gaub, H.; Hinterdorfer, P.; Figdor, C.G.; Speller, S.

    2011-01-01

    Single-molecule force spectroscopy studies performed by Atomic Force Microscopes (AFMs) strongly rely on accurately determined cantilever spring constants. Hence, to calibrate cantilevers, a reliable calibration protocol is essential. Although the thermal noise method and the direct Sader method are

  11. An electrochemical-cantilever platform for hybrid sensing applications

    DEFF Research Database (Denmark)

    Fischer, Lee MacKenzie; Dohn, Søren; Boisen, Anja

    2011-01-01

    This work presents a fully-functional, microfabricated electrochemical-cantilever hybrid platform with flow control. A new cantilever chip format is designed, fabricated, and mounted in a custom polymer flow cell. Issues such as leakage and optical/electrical access are addressed, and combined...

  12. Three-way flexible cantilever probes for static contact

    International Nuclear Information System (INIS)

    Wang, Fei; Petersen, Dirch H; Hansen, Christian; Mortensen, Dennis; Friis, Lars; Hansen, Ole; Jensen, Helle V

    2011-01-01

    In micro four-point probe measurements, three-way flexible L-shaped cantilever probes show significant advantages over conventional straight cantilever probes. The L-shaped cantilever allows static contact to the sample surface which reduces the frictional wear of the cantilever tips. We analyze the geometrical design space that must be fulfilled for the cantilevers to obtain static contact with the test sample. The design space relates the spring constant tensor of the cantilevers to the minimal value of the static tip-to-sample friction coefficient. Using an approximate model, we provide the analytical calculation of the compliance matrix of the L-shaped cantilever. Compared to results derived from finite element model simulations, the theoretical model provides a good qualitative analysis while deviations for the absolute values are seen. From a statistical analysis, the deviation is small for cantilevers with low effective spring constants, while the deviation is significant for large spring constants where the quasi one-dimensional approximation is no longer valid

  13. Use of cantilever mechanics for impacted teeth: case series.

    Science.gov (United States)

    Paduano, Sergio; Spagnuolo, Gianrico; Franzese, Gerardo; Pellegrino, Gioacchino; Valletta, Rosa; Cioffi, Iacopo

    2013-01-01

    This paper describes the orthodontic treatment, and the biomechanics of cantilevers for the impaction of permanent teeth in youngs, adolescents, and adults. In these case series, multibracket straightwire fixed appliances, together with cantilever mechanics, were used to treat the impaired occlusion.

  14. Fabrication of resonant micro cantilevers with integrated transparent fluidic channel

    DEFF Research Database (Denmark)

    Khan, Faheem; Schmid, Silvan; Davis, Zachary James

    2011-01-01

    be visually observed through the transparent fluidic channel. The resonant frequency of the cantilever is changed by the fluid inside the channel, due to the change in mass. The shift in the resonant frequency can be translated into a density of the fluid or into the presence of macro/micro molecules...... of fluids or detect particles suspended in a fluid by sensing the change in total mass of the structure. The 4 × 4 μm2 integrated microfluidic channel makes it possible to flow a fluid through the channel while the cantilevers are resonating. The movement of any particles (present in the fluid) can......Microfabricated cantilevers are proving their potential as excellent tools for analysis applications. In this paper, we describe the design, fabrication and testing of resonant micro cantilevers with integrated transparent fluidic channels. The cantilevers have been devised to measure the density...

  15. Cantilever arrays with self-aligned nanotips of uniform height

    International Nuclear Information System (INIS)

    Koelmans, W W; Peters, T; Berenschot, E; De Boer, M J; Siekman, M H; Abelmann, L

    2012-01-01

    Cantilever arrays are employed to increase the throughput of imaging and manipulation at the nanoscale. We present a fabrication process to construct cantilever arrays with nanotips that show a uniform tip–sample distance. Such uniformity is crucial, because in many applications the cantilevers do not feature individual tip–sample spacing control. Uniform cantilever arrays lead to very similar tip–sample interaction within an array, enable non-contact modes for arrays and give better control over the load force in contact modes. The developed process flow uses a single mask to define both tips and cantilevers. An additional mask is required for the back side etch. The tips are self-aligned in the convex corner at the free end of each cantilever. Although we use standard optical contact lithography, we show that the convex corner can be sharpened to a nanometre scale radius by an isotropic underetch step. The process is robust and wafer-scale. The resonance frequencies of the cantilevers within an array are shown to be highly uniform with a relative standard error of 0.26% or lower. The tip–sample distance within an array of up to ten cantilevers is measured to have a standard error around 10 nm. An imaging demonstration using the AFM shows that all cantilevers in the array have a sharp tip with a radius below 10 nm. The process flow for the cantilever arrays finds application in probe-based nanolithography, probe-based data storage, nanomanufacturing and parallel scanning probe microscopy. (paper)

  16. Terahertz Nanofocusing with Cantilevered Terahertz-Resonant Antenna Tips.

    Science.gov (United States)

    Mastel, Stefan; Lundeberg, Mark B; Alonso-González, Pablo; Gao, Yuanda; Watanabe, Kenji; Taniguchi, Takashi; Hone, James; Koppens, Frank H L; Nikitin, Alexey Y; Hillenbrand, Rainer

    2017-11-08

    We developed THz-resonant scanning probe tips, yielding strongly enhanced and nanoscale confined THz near fields at their tip apex. The tips with length in the order of the THz wavelength (λ = 96.5 μm) were fabricated by focused ion beam (FIB) machining and attached to standard atomic force microscopy (AFM) cantilevers. Measurements of the near-field intensity at the very tip apex (25 nm radius) as a function of tip length, via graphene-based (thermoelectric) near-field detection, indicate their first and second order geometrical antenna resonances for tip length of 33 and 78 μm, respectively. On resonance, we find that the near-field intensity is enhanced by one order of magnitude compared to tips of 17 μm length (standard AFM tip length), which is corroborated by numerical simulations that further predict remarkable intensity enhancements of about 10 7 relative to the incident field. Because of the strong field enhancement and standard AFM operation of our tips, we envision manifold and straightforward future application in scattering-type THz near-field nanoscopy and THz photocurrent nanoimaging, nanoscale nonlinear THz imaging, or nanoscale control and manipulation of matter employing ultrastrong and ultrashort THz pulses.

  17. Nonlinear dynamic analysis of cantilevered piezoelectric energy harvesters under simultaneous parametric and external excitations

    Science.gov (United States)

    Fang, Fei; Xia, Guanghui; Wang, Jianguo

    2018-02-01

    The nonlinear dynamics of cantilevered piezoelectric beams is investigated under simultaneous parametric and external excitations. The beam is composed of a substrate and two piezoelectric layers and assumed as an Euler-Bernoulli model with inextensible deformation. A nonlinear distributed parameter model of cantilevered piezoelectric energy harvesters is proposed using the generalized Hamilton's principle. The proposed model includes geometric and inertia nonlinearity, but neglects the material nonlinearity. Using the Galerkin decomposition method and harmonic balance method, analytical expressions of the frequency-response curves are presented when the first bending mode of the beam plays a dominant role. Using these expressions, we investigate the effects of the damping, load resistance, electromechanical coupling, and excitation amplitude on the frequency-response curves. We also study the difference between the nonlinear lumped-parameter and distributed-parameter model for predicting the performance of the energy harvesting system. Only in the case of parametric excitation, we demonstrate that the energy harvesting system has an initiation excitation threshold below which no energy can be harvested. We also illustrate that the damping and load resistance affect the initiation excitation threshold.

  18. 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....

  19. 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

    We present a microelectromechanical system (MEMS) based PZT/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass. Most piezoelectric energy harvesting devices use a cantilever beam of a non piezoelectric material as support beneath or in-between the piezoelectric...... materials; it provides mechanical support but it also reduces the power output. In our device we replace the support material with another layer of the piezoelectric material. With the absence of an inactive mechanical support all stresses induced by vibrations will be harvested by the active piezoelectric...

  20. Modelling and analysis of piezoelectric cantilever energy harvester for different proof mass and material proportion

    Science.gov (United States)

    Shashank, R.; Harisha, S. K., Dr; Abhishek, M. C.

    2018-02-01

    Energy harvesting using ambient energy sources is one of the fast growing trends in the world, research and development in the area of energy harvesting is moving progressively to get maximum power output from the existing resources. The ambient sources of energy available in the nature are solar energy, wind energy, thermal energy, vibrational energy etc. out of these methods energy harvesting by vibrational energy sources gain more importance due to its nature of not getting influenced by any environmental parameters and its free availability at anytime and anywhere. The project mainly deals with validating the values of voltage and electrical power output of experimentally conducted energy harvester, varying the parameters of the energy harvester and analyse the effect of the parameters on the performance of the energy harvester and compare the results. The cantilever beam was designed, analysed and simulated using COMSOL multi-physics software. The energy harvester gives an electrical output voltage of the 2.75 volts at a natural frequency of 37.2 Hz and an electrical power of 29μW. Decreasing the percentage of the piezoelectric material and simultaneously increasing the percentage of polymer material (so that total percentage of proportion remains same) increases the electrical voltage and decreases the natural frequency of the beam linearly upto 3.9V and 28.847 Hz till the percentage proportion of the beam was 24% piezoelectric beam and 76% polymer beam when the percentage proportion increased to 26% and 74% natural frequency goes on decreases further but voltage suddenly drops to 2.8V. The voltage generated by energy harvester increases proportionally and reaches 3.7V until weight of the proof mass reaches 4 grams and further increase in the weight of the proof mass decreases the voltage generated by energy harvester. Thus the investigation conveys that the weight of the proof mass and the length of the cantilever beam should be optimised to obtain maximum

  1. Quantitative Boundary Support Characterization for Cantilever MEMS

    Directory of Open Access Journals (Sweden)

    Ion Stiharu

    2007-10-01

    Full Text Available Microfabrication limitations are of concern especially for suspended Micro-Electro-Mechanical-Systems (MEMS microstructures such as cantilevers. The static anddynamic qualities of such microscale devices are directly related to the invariant and variantproperties of the microsystem. Among the invariant properties, microfabrication limitationscan be quantified only after the fabrication of the device through testing. However, MEMSare batch fabricated in large numbers where individual testing is neither possible nor costeffective. Hence, a suitable test algorithm needs to be developed where the test resultsobtained for a few devices can be applied to the whole fabrication batch, and also to thefoundry process in general. In this regard, this paper proposes a method to test MEMScantilevers under variant electro-thermal influences in order to quantify the effectiveboundary support condition obtained for a foundry process. A non-contact optical sensingapproach is employed for the dynamic testing. The Rayleigh-Ritz energy method usingboundary characteristic orthogonal polynomials is employed for the modeling andtheoretical analysis.

  2. Energy harvesting from radio frequency propagation using piezoelectric cantilevers

    KAUST Repository

    Al Ahmad, Mahmoud

    2012-02-01

    This work reports an induced strain in a piezoelectric cantilever due to radio frequency signal propagation. The piezoelectric actuator is coupled to radio frequency (RF) line through a gap of 0.25 mm. When a voltage signal of 10 Vpp propagates in the line it sets an alternating current in the actuator electrodes. This flowing current drives the piezoelectric cantilever to mechanical movement, especially when the frequency of the RF signal matches the mechanical resonant frequency of the cantilever. Output voltage signals versus frequency for both mechanical vibrational and RF signal excitations have been measured using different loads.© 2011 Elsevier Ltd. All rights reserved.

  3. Buckled cantilevers for out-of-plane platforms

    International Nuclear Information System (INIS)

    Johnstone, R W; Ma, A H; Sameoto, D; Parameswaran, M; Leung, A M

    2008-01-01

    In this paper, we show how surface-micromachined buckled cantilevers can be used to construct out-of-plane structures. We include the relevant theory necessary to predict the height and angle of plates attached to buckled cantilevers, as well as the mechanical stresses involved in assembly. These platforms can be assembled to any angle between 0° and 90° with respect to the substrate by changing the attachment point and the amount of deflection. Example devices were fabricated using PolyMUMPs(TM) and assembled. Using these devices, the deflection of the buckled cantilevers was verified, as well as the placement for raised platforms

  4. Polymer cantilever platform for dielectrophoretic assembly of carbon nanotubes

    DEFF Research Database (Denmark)

    Johansson, Alicia; Calleja, M.; Dimaki, Maria

    2004-01-01

    A polymer cantilever platform for dielectrophoretic assembly of carbon nanotubes has been designed and realized. Multi-walled carbon nanotubes from aqueous solution have been assembled between two metal electrodes that are separated by 2 mu m and embedded in the polymer cantilever. The entire chip......, except for the metallic electrodes and wiring, was fabricated in the photoresist SU-8. SU-8 allows for an inexpensive, flexible and fast fabrication method, and the cantilever platform provides a hydrophobic surface that should be well suited for nanotube assembly. The device can be integrated in a micro...

  5. Enhanced piezoelectric wind energy harvesting based on a buckled beam

    Science.gov (United States)

    Zhang, Jiantao; Zhang, Jia; Shu, Chang; Fang, Zhou

    2017-05-01

    In order to improve the wind energy conversion efficiency, this study entails a concept utilizing the buckling behavior of a buckled beam to induce large amplitude oscillations in a PVDF beam harvester. Specifically, when the buckled beam subjected to the buckling load is in an unstable condition, the wind load can trigger the drastic vibration of the PVDF beam harvester. Experimental results demonstrate that the output performances of the proposed harvester are improved dramatically compared with a traditional cantilever beam harvester.

  6. Piezoceramic Cantilever Sensor Design for Weak-Impact Detection on Plates

    Directory of Open Access Journals (Sweden)

    Young-Sup Lee

    2012-01-01

    Full Text Available A piezoelectric cantilever type sensor for locating the precise weak-impact or touch position on a plate is presented in this paper. Since the importance of human-computer interface such as a touch panel system has been rapidly increasing recently, this study could suggest an appropriate sensor for the detection of a weak-impact point effectively and accurately for such a system. This sensor detects the out-of-plane vibration of a panel when a touch with a finger or pen is applied on it. The sensor is made with a steel beam and a single crystal PMN-PT patch is bonded on the beam, which is designed to detect the base vibration of the panel. The sensor was designed, manufactured to verify the detect ability of a weak-impact and attached on two different plates of a glass of 400 × 400 × 4 mm and a wooden MDF of 600 × 600 × 9 mm. The experiment result of the sensor was compared with that of an accelerometer which can also be used for the same purpose and shows clear weak-impact responses with a narrow-band property at its resonant frequency. It is expected that the cantilever type sensor in this study could be applied to make a simple flat plate into a touch panel when the time difference of arrivals method is used to locate the weak-impact point.

  7. Influence of cantilevered sheet pile deflection on adjacent roadways.

    Science.gov (United States)

    2009-06-01

    Cantilevered sheet pile walls are often used adjacent roadways as temporary support during construction. Excess movement of these walls has led to excessive roadway distress causing additional repairs to be necessary. This study assessed the effects ...

  8. Phase imaging quality improvement by modification of AFM probes' cantilever.

    Science.gov (United States)

    Skibinski, J; Rebis, J; Kaczmarek, L; Wejrzanowski, T; Plocinski, T; Rozniatowski, K

    2018-03-01

    Imaging of the surface of materials by atomic force microscopy under tapping and phase imaging mode, with use of modified probes is addressed. In this study, the circularly shaped holes located in varying distance from the probe base, were cut out by focused ion beam. Such modification was a consequence of the results of the previous experiments (probe tip sharpening and cantilever thinning) where significant improvement of image quality in tapping and phase imaging mode has been revealed. The solution proposed herein gives similar results, but is much simpler from the technological point of view. Shorter exposition time of the tip onto gallium ions during FIB processing allows to reduce material degradation. The aim of this modification was to change harmonic oscillators' properties in the simplest and fastest way, to obtain stronger signal for higher resonant frequencies, which can be advantageous for improving the quality of imaging in PI mode. Probes shaped in that way were used for AFM investigations with Bruker AFM nanoscope 8. As a testing material, titanium roughness standard sample, supplied by Bruker, was used. The results have shown that the modifications performed within these studies influence the oscillation of the probes, which in some cases may result in deterioration of the imaging quality under tapping mode for one or both self-resonant frequencies. However, phase imaging results obtained using modified probes are of higher quality. The numerical simulations performed by application of finite element method were used to explain the results obtained experimentally. Phenomenon described within this study allows to apply developed modelling methodology for prediction of effects of various modifications on the probes' tip, and as a result, to predict how proposed modifications will affect AFM imaging quality. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

  9. Piezoresistive cantilever force-clamp system

    International Nuclear Information System (INIS)

    Park, Sung-Jin; Petzold, Bryan C.; Pruitt, Beth L.; Goodman, Miriam B.

    2011-01-01

    We present a microelectromechanical device-based tool, namely, a force-clamp system that sets or ''clamps'' the scaled force and can apply designed loading profiles (e.g., constant, sinusoidal) of a desired magnitude. The system implements a piezoresistive cantilever as a force sensor and the built-in capacitive sensor of a piezoelectric actuator as a displacement sensor, such that sample indentation depth can be directly calculated from the force and displacement signals. A programmable real-time controller operating at 100 kHz feedback calculates the driving voltage of the actuator. The system has two distinct modes: a force-clamp mode that controls the force applied to a sample and a displacement-clamp mode that controls the moving distance of the actuator. We demonstrate that the system has a large dynamic range (sub-nN up to tens of μN force and nm up to tens of μm displacement) in both air and water, and excellent dynamic response (fast response time, <2 ms and large bandwidth, 1 Hz up to 1 kHz). In addition, the system has been specifically designed to be integrated with other instruments such as a microscope with patch-clamp electronics. We demonstrate the capabilities of the system by using it to calibrate the stiffness and sensitivity of an electrostatic actuator and to measure the mechanics of a living, freely moving Caenorhabditis elegans nematode.

  10. Measurement of Mechanical Properties of Cantilever Shaped Materials

    Directory of Open Access Journals (Sweden)

    Thomas Thundat

    2008-05-01

    Full Text Available Microcantilevers were first introduced as imaging probes in Atomic Force Microscopy (AFM due to their extremely high sensitivity in measuring surface forces. The versatility of these probes, however, allows the sensing and measurement of a host of mechanical properties of various materials. Sensor parameters such as resonance frequency, quality factor, amplitude of vibration and bending due to a differential stress can all be simultaneously determined for a cantilever. When measuring the mechanical properties of materials, identifying and discerning the most influential parameters responsible for the observed changes in the cantilever response are important. We will, therefore, discuss the effects of various force fields such as those induced by mass loading, residual stress, internal friction of the material, and other changes in the mechanical properties of the microcantilevers. Methods to measure variations in temperature, pressure, or molecular adsorption of water molecules are also discussed. Often these effects occur simultaneously, increasing the number of parameters that need to be concurrently measured to ensure the reliability of the sensors. We therefore systematically investigate the geometric and environmental effects on cantilever measurements including the chemical nature of the underlying interactions. To address the geometric effects we have considered cantilevers with a rectangular or circular cross section. The chemical nature is addressed by using cantilevers fabricated with metals and/or dielectrics. Selective chemical etching, swelling or changes in Young’s modulus of the surface were investigated by means of polymeric and inorganic coatings. Finally to address the effect of the environment in which the cantilever operates, the Knudsen number was determined to characterize the molecule-cantilever collisions. Also bimaterial cantilevers with high thermal sensitivity were used to discern the effect of temperature

  11. Coded Splitting Tree Protocols

    DEFF Research Database (Denmark)

    Sørensen, Jesper Hemming; Stefanovic, Cedomir; Popovski, Petar

    2013-01-01

    This paper presents a novel approach to multiple access control called coded splitting tree protocol. The approach builds on the known tree splitting protocols, code structure and successive interference cancellation (SIC). Several instances of the tree splitting protocol are initiated, each...... instance is terminated prematurely and subsequently iterated. The combined set of leaves from all the tree instances can then be viewed as a graph code, which is decodable using belief propagation. The main design problem is determining the order of splitting, which enables successful decoding as early...... as possible. Evaluations show that the proposed protocol provides considerable gains over the standard tree splitting protocol applying SIC. The improvement comes at the expense of an increased feedback and receiver complexity....

  12. Split Cord Malformations

    Directory of Open Access Journals (Sweden)

    Yurdal Gezercan

    2015-06-01

    Full Text Available Split cord malformations are rare form of occult spinal dysraphism in children. Split cord malformations are characterized by septum that cleaves the spinal canal in sagittal plane within the single or duplicated thecal sac. Although their precise incidence is unknown, split cord malformations are exceedingly rare and represent %3.8-5 of all congenital spinal anomalies. Characteristic neurological, urological, orthopedic clinical manifestations are variable and asymptomatic course is possible. Earlier diagnosis and surgical intervention for split cord malformations is associated with better long-term fuctional outcome. For this reason, diagnostic imaging is indicated for children with associated cutaneous and orthopedic signs. Additional congenital anomalies usually to accompany the split cord malformations. Earlier diagnosis, meticuolus surgical therapy and interdisciplinary careful evaluation and follow-up should be made for good prognosis. [Cukurova Med J 2015; 40(2.000: 199-207

  13. An elastography method based on the scanning contact resonance of a piezoelectric cantilever

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Ji; Li, Faxin, E-mail: lifaxin@pku.edu.cn [State Key Lab for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing 100871, China and HEDPS, Center for Applied Physics and Technologies, Peking University, Beijing 100871 (China)

    2013-12-15

    Purpose: Most tissues may become significantly stiffer than their normal states when there are lesions inside. The tissue's modulus can then act as an identification parameter for clinic diagnosis of tumors or fibrosis, which leads to elastography. This study introduces a novel elastography method that can be used for modulus imaging of superficial organs. Methods: This method is based on the scanning contact-resonance of a unimorph piezoelectric cantilever. The cantilever vibrates in its bending mode with the tip pressed tightly on the sample. The contact resonance frequency of the cantilever-sample system is tracked at each scanning point, from which the sample's modulus can be derived based on a beam dynamic model and a contact mechanics model. Scanning is performed by a three-dimensional motorized stage and the whole system is controlled by a homemade software program based on LabVIEW. Results: Testing onin vitro beef tissues indicates that the fat and the muscle can be easily distinguished using this system, and the accuracy of the modulus measurement can be comparable with that of nanoindentation. Imaging on homemade gelatin phantoms shows that the depth information of the abnormalities can be qualitatively obtained by varying the pressing force. The detection limit of this elastography method is specially examined both experimentally and numerically. Results show that it can detect the typical lesions in superficial organs with the depth of several centimeters. The lateral resolution of this elastography method/system is better than 0.5 mm, and could be further enhanced by using more scanning points. Conclusions: The proposed elastography system can be regarded as a sensitive palpation robot, which may be very promising in early diagnosis of tumors in superficial organs such as breast and thyroid.

  14. Bandgap measurements and the peculiar splitting of E{sub 2}{sup H} phonon modes of In{sub x}Al{sub 1-x}N nanowires grown by plasma assisted molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Tangi, Malleswararao; Mishra, Pawan; Janjua, Bilal; Ng, Tien Khee; Prabaswara, Aditya; Ooi, Boon S., E-mail: boon.ooi@kaust.edu.sa [Photonics Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia); Anjum, Dalaver H.; Yang, Yang [Adavanced nanofabrication Imaging and characterization, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia); Albadri, Abdulrahman M.; Alyamani, Ahmed Y.; El-Desouki, Munir M. [National Center for Nanotechnology, King Abdulaziz City for Science and Technology (KACST), Riyadh 11442-6086 (Saudi Arabia)

    2016-07-28

    The dislocation free In{sub x}Al{sub 1-x}N nanowires (NWs) are grown on Si(111) by nitrogen plasma assisted molecular beam epitaxy in the temperature regime of 490 °C–610 °C yielding In composition ranges over 0.50 ≤ x ≤ 0.17. We study the optical properties of these NWs by spectroscopic ellipsometry (SE), photoluminescence, and Raman spectroscopies since they possesses minimal strain with reduced defects comparative to the planar films. The optical bandgap measurements of In{sub x}Al{sub 1-x}N NWs are demonstrated by SE where the absorption edges of the NW samples are evaluated irrespective of substrate transparency. A systematic Stoke shift of 0.04–0.27 eV with increasing x was observed when comparing the micro-photoluminescence spectra with the Tauc plot derived from SE. The micro-Raman spectra in the NWs with x = 0.5 showed two-mode behavior for A{sub 1}(LO) phonons and single mode behavior for E{sub 2}{sup H} phonons. As for x = 0.17, i.e., high Al content, we observed a peculiar E{sub 2}{sup H} phonon mode splitting. Further, we observe composition dependent frequency shifts. The 77 to 600 K micro-Raman spectroscopy measurements show that both AlN- and InN-like modes of A{sub 1}(LO) and E{sub 2}{sup H} phonons in In{sub x}Al{sub 1-x}N NWs are redshifted with increasing temperature, similar to that of the binary III group nitride semiconductors. These studies of the optical properties of the technologically important In{sub x}Al{sub 1-x}N nanowires will path the way towards lasers and light-emitting diodes in the wavelength of the ultra-violet and visible range.

  15. Cantilever-based micro-particle filter with simultaneous single particle detection

    DEFF Research Database (Denmark)

    Noeth, Nadine-Nicole; Keller, Stephan Sylvest; Boisen, Anja

    2011-01-01

    -particles from a liquid. A hole-array is integrated into a micro-cantilever, which is inserted into a microfluidic channel perpendicular to the flow. A metal pad at the apex of the cantilever enables an optical read-out of the deflection of the cantilever. When a micro-particle is too large to pass a hole...... in the cantilever, clogging of the holes increases the flow resistance of the cantilever. This causes a bending of the device, which can be detected by the optical read-out system. By arranging an array of such cantilevers with different hole sizes, separation by size can be achieved. In this paper a proof...

  16. SiC-Based Miniature High-Temperature Cantilever Anemometer

    Science.gov (United States)

    Okojie, Robert S.; Fralick, Gustave; Saad, George J.

    2004-01-01

    The figure depicts a miniature cantilever-type anemometer that has been developed as a prototype of compact, relatively nonintrusive anemometers that can function at temperatures up to 600 C and that can be expected to be commercially mass-producible at low cost. The design of this anemometer, and especially the packaging aspect of the design, is intended to enable measurement of turbulence in the high-temperature, high-vibration environment of a turbine engine or in any similar environment. The main structural components of the anemometer include a single-crystal SiC cantilever and two polycrystalline SiC clamping plates, all made from chemical-vapor-deposited silicon carbide. Fabrication of these components from the same basic material eliminates thermal-expansion mismatch, which has introduced spurious thermomechanical stresses in cantilever-type anemometers of prior design. The clamping plates are heavily oxidized to improve electrical insulation at high temperature. A cavity that serves as a receptacle for the clamped end of the cantilever is etched into one end of one clamping plate. Trenches that collectively constitute a socket for a multipin electrical plug (for connection to external electronic circuitry) are etched into the opposite end of this clamping plate. Metal strips for electrical contact are deposited on one face of the other clamping plate. Piezoresistive single-crystal SiC thin-film strain gauges are etched in the n-type SiC epilayer in a Wheatstone-bridge configuration. Metal contact pads on the cantilever that extend into the clamping-receptacle area, are obtained by deposition and patterning using standard semiconductor photolithography and etching methods. The cantilever and the two clamping plates are assembled into a sandwich structure that is then clamped in a stainless-steel housing. The Wheatstone- bridge carrying SiC cantilever with the metal contact pads on the piezoresistors is slid into the receptacle in the bottom clamping plate

  17. Cantilever with immobilized antibody for liver cancer biomarker detection

    International Nuclear Information System (INIS)

    Wang Shuaipeng; Wang Jingjing; Zhu Yinfang; Yang Jinling; Yang Fuhua

    2014-01-01

    A novel cantilever array-based bio-sensor was batch-fabricated with IC compatible MEMS technology for precise liver cancer bio-marker detection. A micro-cavity was designed in the free end of the cantilever for local antibody-immobilization, thus the adsorption of the cancer biomarker takes place only in the local region of the cantilever instead of the whole lever, and the effect of adsorption-induced k variation can be dramatically reduced. These structural features offer several advantages: high sensitivity, high throughput, high mass detection accuracy, and a portable system. In addition, an analytical model has been established to eliminate the effect of the adsorption-induced lever stiffness change and has been applied to the precise mass detection of the cancer biomarker AFP; the experimentally detected AFP antigen mass by the sensor (7.6 pg/mL) is quite close to the calculated one (5.5 pg/mL), two orders of magnitude better than those of the fully antibody-immobilized cantilever sensor. These approaches can promote real applications of the cantilever sensors in cancer diagnosis. (semiconductor devices)

  18. A piezoelectric vibration harvester based on clamped-guided beams

    NARCIS (Netherlands)

    Wang, Z.; Matova, S.; Elfrink, R.; Jambunathan, M.; Nooijer, C. de; Schaijk, R. van; Vullers, R.J.M.

    2012-01-01

    The paper addresses the design, modeling, fabrication and experimental results of a piezoelectric energy harvester based on clamped-guided beams. The design is featured by shorter mass displacement and higher reliability than cantilever beams. Two separate sets of capacitors allow exploiting both

  19. Split Malcev algebras

    Indian Academy of Sciences (India)

    project of the Spanish Ministerio de Educación y Ciencia MTM2007-60333. References. [1] Calderón A J, On split Lie algebras with symmetric root systems, Proc. Indian. Acad. Sci (Math. Sci.) 118(2008) 351–356. [2] Calderón A J, On split Lie triple systems, Proc. Indian. Acad. Sci (Math. Sci.) 119(2009). 165–177.

  20. Pembuatan Cantilever Bridge Anterior Rahang Atas sebagai Koreksi Estetik

    Directory of Open Access Journals (Sweden)

    Yusrina Sumartati

    2012-12-01

    Full Text Available Latar belakang. Kehilangan gigi anterior rahang atas mengakibatkan gangguan fungsi fonetik dan estetik. Gangguan fungsi estetik menyebabkan pasie menjadi rendah diri. Kondisi ini dapat diatasi oleh dokter gigi, salah satunya dengan pembuatan cantilever bridge. Tujuan. Penulisan ini yaitu untuk memberi informasi bahwa pada kasus kehilangan gigi-gigi anterior rahang atas dengan space yang telah menyempit dan malposisi gigi dapat dibuatkan protesa berupa gigi tiruan cekat dengan desain cantilever bridge. Kasus dan perawatan. Laporan kasus ini membahas tentang pasien perempuan umur 39 tahun yang datang ke Rumah Sakit Gigi dan Mulut Prof. Soedomo, dengan keluhan merasa kurang percaya diri karena gigi depan rahang atas hilang sejak 5 tahun yang lalu akibat kecelakaan. Gigi-gigi anterior rahang atas yang masih ada mengalami malposisi akibat pemakaian gigi tiruan sebagian lepasan yang tidak baik. Perawatan yang dilakukan adalah dengan pembuatan cantilever bridge pada gigi 11, 12, 13 dan 21, 22, 23. Kesimpulan. Gangguan fungsi estetik pada gigi anterior rahang atas dapat diatasi dengan pembuatan cantilever bridge.   Background. Maxillary anteriortooth loss resulting in impaired function of phonetic and aesthetic. Impaired function of aesthetic cause patients to become self conscious. This condition can be treated by a dentist, one with a cantilever bridge. Purpose. To inform that in case of missing anterior teeth of the upper jaw with a space that has been narrowed, and malposition of teeth can be made prosthesis denture fixed bridge with a cantilever design. Case and treatment. This case report discusses the 39 years old female patient who came to he Dental Hospital Prof. Soedomo, with complaints of feeling less confident due to the maxillary front teeth missing since 5 years ago due to an accident. Anterior teeth of the upper jaw are still experiencing malposition due to the use of removable partial dentures are not good. The treatment is done is by

  1. Flat profile laser beam shaper

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Todd R.

    2017-09-12

    A system for shaping a beam comprises an emitter for emitting coherent electromagnetic radiation. Birefringent displacers are configured between the emitter and a target wherein the at least two birefringent displacers split the coherent electromagnetic radiation into a plurality of coherent parallel beams of electromagnetic radiation thereby producing a shaped wave front of the coherent parallel beams of electromagnetic radiation.

  2. On the electromechanical modelling of a resonating nano-cantilever-based transducer

    DEFF Research Database (Denmark)

    Teva, J.; Abadal, G.; Davis, Zachary James

    2004-01-01

    An electromechanical model for a transducer based on a lateral resonating cantilever is described. The on-plane vibrations of the cantilever are excited electrostatically by applying DC and AC voltages from a driver electrode placed closely parallel to the cantilever. The model predicts the stati...

  3. Integrated optical readout for miniaturization of cantilever-based sensor system

    DEFF Research Database (Denmark)

    Nordström, Maria; Zauner, Dan; Calleja, Montserrat

    2007-01-01

    The authors present the fabrication and characterization of an integrated optical readout scheme based on single-mode waveguides for cantilever-based sensors. The cantilever bending is read out by monitoring changes in the optical intensity of light transmitted through the cantilever that also acts...

  4. Piezoresistive cantilevers for characterizing thin-film gold electrical contacts

    Science.gov (United States)

    Pruitt, Beth L.

    The electronics packaging and testing industry is interested in new methods for making contacts to electronic chips to allow improvement or replacement of existing interconnect technologies. One approach involves the use of flexible contact structures integrated with the package or the testing apparatus which allow the device to be fully contacted by placing and pressing the interconnect array into contact. This technoOlogy depends on the properties of low-force electrical contacts. The research presented is a careful characterization of the electromechanical properties of such contacts, using instrumented MEMS force sensors. This work provides a sensor, measurement system and methodology for low force contact resistance data collection. This research includes the design, fabrication, and characterization of a micromechanical force sensor integrated with a 4-wire electrical contact characterization capability, a set of parametric measurements in the 10nN-10mN regime, and the development of qualitative design rules for small force thin film gold electrical contacts. The sensor consists of a silicon cantilever beam with a piezoresistive force sensor suitable for high-accuracy force measurements in the mN-nN range. The contact tips consist of a glass spheres for a controlled contact geometry as well as polystyrene spheres for highly-compliant contact structures. The contact halves are coated with varying thicknesses of evaporated, sputtered, or plated thin film gold. Combined with AFM scans and nanoindentation hardness measurements, correlations are found between the contact behavior, resistance measurements, and material characteristics over varied contact sizes, film types, thicknesses, and substrates. Mean stable contact resistance (elastic contact theory are attributed to the presence of asperities on the contact spheres, plasticity in the films, and differences in material properties for thin film vs. bulk form. The two most significant factors affecting contact

  5. Electron beam control for barely separated beams

    Energy Technology Data Exchange (ETDEWEB)

    Douglas, David R.; Ament, Lucas J. P.

    2017-04-18

    A method for achieving independent control of multiple beams in close proximity to one another, such as in a multi-pass accelerator where coaxial beams are at different energies, but moving on a common axis, and need to be split into spatially separated beams for efficient recirculation transport. The method for independent control includes placing a magnet arrangement in the path of the barely separated beams with the magnet arrangement including at least two multipole magnets spaced closely together and having a multipole distribution including at least one odd multipole and one even multipole. The magnetic fields are then tuned to cancel out for a first of the barely separated beams to allow independent control of the second beam with common magnets. The magnetic fields may be tuned to cancel out either the dipole component or tuned to cancel out the quadrupole component in order to independently control the separate beams.

  6. Nano-DTA and nano-DSC with cantilever-type calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Nakabeppu, Osamu, E-mail: onakabep@meiji.ac.jp [Meiji University, School of Science and Technology, Department of Mechanical Engineering, Higashimita 1-1-1, Tama-ku, Kawasaki 214-8571 (Japan); Deno, Kohei [Tokyo Institute of Technology, Graduate School of Science and Engineering, Department of Mechanical Sciences and Engineering (Japan)

    2016-08-10

    Highlights: • Nanocalorimetry with original cantilever type calorimeters. • The calorimeters showed the enthalpy resolution of 200 nJ level. • Nano-DTA of a binary alloy captured a probabilistic peak after solidification. • Power compensation DSC of a microgram level sample was demonstrated. • The DSC and DTA behavior were explained with a lumped model. - Abstract: Differential thermal analysis (DTA) and differential scanning calorimetry (DSC) of the minute samples in the range of microgram to nanogram were studied using original cantilever-type calorimeters. The micro-fabricated calorimeter with a heater and thermal sensors was able to perform a fast temperature scan at above 1000 K/s and a high-resolution heat measurement. The DTA of minuscule metal samples demonstrated some advances such as the thermal analysis of a 20 ng level indium and observation of a strange phase transition of a binary alloy. The power compensation type DSC using a thermal feedback system was also performed. Thermal information of a microgram level sample was observed as splitting into the DSC and DTA signals because of a mismatch between the sample and the calorimeter. Although there remains some room for improvement in terms of the heat flow detection, the behavior of the compensation system in the DSC was theoretically understood through a lumped model. Those experiments also produced some findings, such as a fin effect with sample loading, a measurable weight range, a calibration of the calorimeter and a product design concept. The development of the nano-DTA and nano-DSC will enable breakthroughs for the fast calorimetry of the microscopic size samples.

  7. Nano-DTA and nano-DSC with cantilever-type calorimeter

    International Nuclear Information System (INIS)

    Nakabeppu, Osamu; Deno, Kohei

    2016-01-01

    Highlights: • Nanocalorimetry with original cantilever type calorimeters. • The calorimeters showed the enthalpy resolution of 200 nJ level. • Nano-DTA of a binary alloy captured a probabilistic peak after solidification. • Power compensation DSC of a microgram level sample was demonstrated. • The DSC and DTA behavior were explained with a lumped model. - Abstract: Differential thermal analysis (DTA) and differential scanning calorimetry (DSC) of the minute samples in the range of microgram to nanogram were studied using original cantilever-type calorimeters. The micro-fabricated calorimeter with a heater and thermal sensors was able to perform a fast temperature scan at above 1000 K/s and a high-resolution heat measurement. The DTA of minuscule metal samples demonstrated some advances such as the thermal analysis of a 20 ng level indium and observation of a strange phase transition of a binary alloy. The power compensation type DSC using a thermal feedback system was also performed. Thermal information of a microgram level sample was observed as splitting into the DSC and DTA signals because of a mismatch between the sample and the calorimeter. Although there remains some room for improvement in terms of the heat flow detection, the behavior of the compensation system in the DSC was theoretically understood through a lumped model. Those experiments also produced some findings, such as a fin effect with sample loading, a measurable weight range, a calibration of the calorimeter and a product design concept. The development of the nano-DTA and nano-DSC will enable breakthroughs for the fast calorimetry of the microscopic size samples.

  8. On the dynamics of tapered vibro-impacting cantilever with tip mass

    Energy Technology Data Exchange (ETDEWEB)

    Gandhi, P. S.; Vyas, Vishal [Suman Mashruwala Advanced Microengineering Laboratory, Dept. of Mechanical Engineering, Indian Institute of Technology - Bombay, Mumai (India)

    2017-01-15

    This paper explores nonlinear dynamic behavior of vibro-impacting tapered cantilever with tip mass with regard to frequency response analysis. A typical frequency response curve of vibro-impacting beams displays well-known resonance frequency shift along with a hysteric jump and drop phenomena. We did a comprehensive parametric analysis capturing the effects of taper, tip-mass, stop location, and gap on the non-smooth frequency response. Analysis is presented in a non-dimensional form useful for other similar cases. Simulation results are further validated with corresponding experimental results for a few cases. Illustrative comparison of simulation results for varying parameters brings out several interesting aspects of variation in the nonlinear behavior.

  9. Real-time moving horizon estimation for a vibrating active cantilever

    Science.gov (United States)

    Abdollahpouri, Mohammad; Takács, Gergely; Rohaľ-Ilkiv, Boris

    2017-03-01

    Vibrating structures may be subject to changes throughout their operating lifetime due to a range of environmental and technical factors. These variations can be considered as parameter changes in the dynamic model of the structure, while their online estimates can be utilized in adaptive control strategies, or in structural health monitoring. This paper implements the moving horizon estimation (MHE) algorithm on a low-cost embedded computing device that is jointly observing the dynamic states and parameter variations of an active cantilever beam in real time. The practical behavior of this algorithm has been investigated in various experimental scenarios. It has been found, that for the given field of application, moving horizon estimation converges faster than the extended Kalman filter; moreover, it handles atypical measurement noise, sensor errors or other extreme changes, reliably. Despite its improved performance, the experiments demonstrate that the disadvantage of solving the nonlinear optimization problem in MHE is that it naturally leads to an increase in computational effort.

  10. Vibration suppression of a rotating flexible cantilever pipe conveying fluid using piezoelectric layers

    Directory of Open Access Journals (Sweden)

    S. Khajehpour

    Full Text Available AbstractIn this study, the governing equations of a rotating cantilever pipe conveying fluid are derived and the longitudinal and lateral induced vibrations are controlled. The pipe considered as an Euler Bernoulli beam with tip mass which piezoelectric layers attached both side of it as sensors and actuators. The follower force due to the fluid discharge causes both conservative and non-conservative work. For mathematical modeling, the Lagrange-Rayleigh-Ritz technique is utilized. An adaptive-robust control scheme is applied to suppress the vibration of the pipe. The adaptive-robust control method is robust against parameter uncertainties and disturbances. Finally, the system is simulated and the effects of varying parameters are studied. The simulation results show the excellent performance of the controller.

  11. 3D Printing of Cantilever-Type Microstructures by Stereolithography of Ferromagnetic Photopolymers.

    Science.gov (United States)

    Credi, Caterina; Fiorese, Alessandro; Tironi, Marco; Bernasconi, Roberto; Magagnin, Luca; Levi, Marinella; Turri, Stefano

    2016-10-05

    In the present work, prototypes of polymeric cantilever-based magnetic microstructures were fabricated by means of stereolithography (SL). To this end, a UV-curable system suitable for high-resolution SL-processing was formulated by blending a bifunctional acrylic monomer with photoinitiator and visible dye whose content was tuned to tailor resin SL sensitivity. Subsequently, to confer ferromagnetic properties to the photopolymer, two different strategies were implemented. A two-step approach involved selective deposition of a metal layer on photopolymer SL-cured surfaces through an electroless plating process. On the other hand, SL-processable ferromagnetically responsive nanocomposites (FRCs) were obtained by directly loading magnetite nanoparticles within the photopolymer matrix. In order to achieve high-printing resolution, resin SL sensitivities were studied as a function of the various additives contents. Photocalorimetric analyses were also performed to investigate the photopolymer conversion efficiency upon light exposure. High-performing formulations were characterized by reduced penetration depth (printing of micrometric structures. Finally, the self-standing characteristics of the resin combined with the layered-fashion deposition typical of the 3D printing technologies were exploited for the fabrication of cantilever (CL)-based beams presented as possible magnetic sensors. As a demonstration of the feasibility of the two approaches, the magnetic beams were successfully actuated and their sensing performances in terms of static deflection vs applied magnetic field applied were qualitatively studied. Being not restricted to CL-based geometries, the combination of SL-printing with the formulation of novel smart photopolymers open the way toward the fabrication of high-customized complex 3D models integrating functional microstructures.

  12. Optimised cantilever biosensor with piezoresistive read-out

    DEFF Research Database (Denmark)

    Rasmussen, Peter; Thaysen, J.; Hansen, Ole

    2003-01-01

    We present a cantilever-based biochemical sensor with piezoresistive read-out which has been optimised for measuring surface stress. The resistors and the electrical wiring on the chip are encapsulated in low-pressure chemical vapor deposition (LPCVD) silicon nitride, so that the chip is well...

  13. Strategy Guideline: Quality Management in Existing Homes - Cantilever Floor Example

    Energy Technology Data Exchange (ETDEWEB)

    Taggart, J. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Sikora, J. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Wiehagen, J. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Wood, A. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States)

    2011-12-01

    This guideline is designed to highlight the QA process that can be applied to any residential building retrofit activity. The cantilevered floor retrofit detailed in this guideline is included only to provide an actual retrofit example to better illustrate the QA activities being presented.

  14. Optimization of sensitivity and noise in piezoresistive cantilevers

    DEFF Research Database (Denmark)

    Yu, Xiaomei; Thaysen, Jacob; Hansen, Ole

    2002-01-01

    , dimension optimized array cantilevers were designed and fabricated by using single-crystal silicon, low-pressure chemical-vapor deposition (LPCVD) amorphous silicon and microcrystalline silicon as piezoresistive layers. Measurement results have shown that the smallest Hooge factor (alpha) was 3.2x10...

  15. Polymer cantilever platform for dielectrophoretic assembly of carbon nanotubes

    DEFF Research Database (Denmark)

    Johansson, Alicia; Calleja, M.; Dimaki, Maria

    2004-01-01

    , except for the metallic electrodes and wiring, was fabricated in the photoresist SU-8. SU-8 allows for an inexpensive, flexible and fast fabrication method, and the cantilever platform provides a hydrophobic surface that should be well suited for nanotube assembly. The device can be integrated in a micro...

  16. Photothermal cantilever actuation for fast single-molecule force spectroscopy

    Science.gov (United States)

    Stahl, Stefan W.; Puchner, Elias M.; Gaub, Hermann E.

    2009-07-01

    Photothermal cantilever excitation provides a fast and easy to implement means to control the deflection of standard atomic force microscopy cantilevers. Minute heat pulses yield deflections on the order of several tens of nanometers or when the deflection is kept constant, forces of several hundreds of piconewton can be applied. In our case these pulses resulted in less than 1 K temperature changes at the sample position. Here we present and characterize the implementation of photothermal actuation for single-molecule force-spectroscopy experiments. When molecules are stretched under force-clamp conditions, fast control cycles that re-establish the pulling force after the rupture of molecular domains are essential for detecting the complete unfolding pattern with high precision. By combining the fast response of photothermal cantilever excitation with a conventional piezoactuator, a fast force-clamp with high accuracy and large working distances is reached. Simple feedback mechanisms and standard cantilever geometries lead to step response times of less than 90 μs, which is more than one order of magnitude faster than those of conventional force-clamp systems that are based only on piezo feedback. We demonstrate the fast and accurate performance of the setup by unfolding a protein construct consisting of one green fluorescent protein and eight surrounding immunoglobulin domains at constant force.

  17. Piezoresistive Cantilever Performance—Part I: Analytical Model for Sensitivity

    Science.gov (United States)

    Park, Sung-Jin; Doll, Joseph C.; Pruitt, Beth L.

    2010-01-01

    An accurate analytical model for the change in resistance of a piezoresistor is necessary for the design of silicon piezoresistive transducers. Ion implantation requires a high-temperature oxidation or annealing process to activate the dopant atoms, and this treatment results in a distorted dopant profile due to diffusion. Existing analytical models do not account for the concentration dependence of piezoresistance and are not accurate for nonuniform dopant profiles. We extend previous analytical work by introducing two nondimensional factors, namely, the efficiency and geometry factors. A practical benefit of this efficiency factor is that it separates the process parameters from the design parameters; thus, designers may address requirements for cantilever geometry and fabrication process independently. To facilitate the design process, we provide a lookup table for the efficiency factor over an extensive range of process conditions. The model was validated by comparing simulation results with the experimentally determined sensitivities of piezoresistive cantilevers. We performed 9200 TSUPREM4 simulations and fabricated 50 devices from six unique process flows; we systematically explored the design space relating process parameters and cantilever sensitivity. Our treatment focuses on piezoresistive cantilevers, but the analytical sensitivity model is extensible to other piezoresistive transducers such as membrane pressure sensors. PMID:20336183

  18. Aluminum nano-cantilevers for high sensitivity mass sensors

    DEFF Research Database (Denmark)

    Davis, Zachary James; Boisen, Anja

    2005-01-01

    We have fabricated Al nano-cantilevers using a very simple one mask contact UV lithography technique with lateral dimensions under 500 nm and vertical dimensions of approximately 100 nm. These devices are demonstrated as highly sensitive mass sensors by measuring their dynamic properties. Further...

  19. AFM cantilever with in situ renewable mercury microelectrode

    NARCIS (Netherlands)

    Schön, Peter Manfred; Geerlings, J.; Tas, Niels Roelof; Sarajlic, Edin

    2013-01-01

    We report here first results obtained on a novel, in situ renewable mercury microelectrode integrated into an atomic force microscopy (AFM) cantilever. Our approach is based on a fountain pen probe with appropriate dimensions enabling reversible filling with(nonwetting) mercury under changing the

  20. Wafer scale coating of polymer cantilever fabricated by nanoimprint lithography

    DEFF Research Database (Denmark)

    Greve, Anders; Dohn, Søren; Keller, Stephan Urs

    2010-01-01

    Microcantilevers can be fabricated in TOPAS by nanoimprint lithography, with the dimensions of 500 ¿m length 4.5 ¿m thickness and 100 ¿m width. By using a plasma polymerization technique it is possible to selectively functionalize individually cantilevers with a polymer coating, on wafer scale...

  1. Development of an Electrochemical-Cantilever Hybrid Platform

    DEFF Research Database (Denmark)

    Fischer, Lee MacKenzie

    for differentielle målinger. Reaktionen for 3 forskellige koncentrationer af kobber ioner blev undersøgt, og et estimat af absorption rate konstanten fundet for Cu-(Cys) og Cu-(CGGH) bindings systemer. Potentiale trin og skanninger blev påtrykt en cantilever i en buffered elektrolyt. Det resulterede i overflade...

  2. Global consequences of a local Casimir force : Adhered cantilever

    NARCIS (Netherlands)

    Svetovoy, V. B.; Melenev, A. E.; Lokhanin, M. V.; Palasantzas, G.

    2017-01-01

    Although stiction is a cumbersome problem for microsystems, it stimulates investigations of surface adhesion. In fact, the shape of an adhered cantilever carries information of the adhesion energy that locks one end to the substrate. We demonstrate here that the system is also sensitive to the

  3. Extension of Ko Straight-Beam Displacement Theory to Deformed Shape Predictions of Slender Curved Structures

    Science.gov (United States)

    Ko, William L.; Fleischer, Van Tran

    2011-01-01

    The Ko displacement theory originally developed for shape predictions of straight beams is extended to shape predictions of curved beams. The surface strains needed for shape predictions were analytically generated from finite-element nodal stress outputs. With the aid of finite-element displacement outputs, mathematical functional forms for curvature-effect correction terms are established and incorporated into straight-beam deflection equations for shape predictions of both cantilever and two-point supported curved beams. The newly established deflection equations for cantilever curved beams could provide quite accurate shape predictions for different cantilever curved beams, including the quarter-circle cantilever beam. Furthermore, the newly formulated deflection equations for two-point supported curved beams could provide accurate shape predictions for a range of two-point supported curved beams, including the full-circular ring. Accuracy of the newly developed curved-beam deflection equations is validated through shape prediction analysis of curved beams embedded in the windward shallow spherical shell of a generic crew exploration vehicle. A single-point collocation method for optimization of shape predictions is discussed in detail

  4. Aspects of Split Supersymmetry

    CERN Document Server

    Arkani-Hamed, N; Giudice, Gian Francesco; Romanino, A

    2005-01-01

    We explore some fundamental differences in the phenomenology, cosmology and model building of Split Supersymmetry compared with traditional low-scale supersymmetry. We show how the mass spectrum of Split Supersymmetry naturally emerges from theories where the dominant source of supersymmetry breaking preserves an $R$ symmetry, characterize the class of theories where the unavoidable $R$-breaking by gravity can be neglected, and point out a new possibility, where supersymmetry breaking is directly communicated at tree level to the visible sector via renormalizable interactions. Next, we discuss possible low-energy signals for Split Supersymmetry. The absence of new light scalars removes all the phenomenological difficulties of low-energy supersymmetry, associated with one-loop flavor and CP violating effects. However, the electric dipole moments of leptons and quarks do arise at two loops, and are automatically at the level of present limits with no need for small phases, making them accessible to several ongo...

  5. Drift study of SU8 cantilevers in liquid and gaseous environments

    DEFF Research Database (Denmark)

    Tenje, Maria; Keller, Stephan Sylvest; Dohn, Søren

    2010-01-01

    We present a study of the drift, in terms of cantilever deflections without probe/target interactions, of polymeric SU8 cantilevers. The drift is measured in PBS buffer (pH 7.4) and under vacuum (1 mbar) conditions. We see that the cantilevers display a large drift in both environments. We believ...... coat the cantilevers with a hydrophobic coating, perfluorodecyltrichlorosilane (FDTS). Fully encapsulating the SU8 cantilever greatly reduces the drift in liquid whereas a less significant change is seen in vacuum....

  6. Suppression of spurious vibration of cantilever in atomic force microscopy by enhancement of bending rigidity of cantilever chip substrate.

    Science.gov (United States)

    Tsuji, Toshihiro; Kobari, Kentaro; Ide, Seishiro; Yamanaka, Kazushi

    2007-10-01

    To improve the precision of dynamic atomic force microscopy (AFM) using cantilever vibration spectra, a simple but effective method for suppressing spurious response (SR) was developed. The dominant origin of SR was identified to be the bending vibration of the cantilever substrate, by the analysis of the frequency of SR. Although a rigid cover pressing the whole surface of the substrate suppressed SR, the utility was insufficient. Then, a method of enhancing the bending rigidity of the substrate by gluing a rigid plate (clamping plate, CP) to the substrate was developed. This chip can be used with an ordinary cantilever holder, so that the reproducibility of SR suppression when attaching and detaching the cantilever chip to the holder was improved. To verify its utility, the evaluation of a microdevice electrode was performed by ultrasonic atomic force microscopy. The delamination at a submicron depth was visualized and the detailed variation of the delamination was evaluated for the first time using clear resonance spectra. The CP method will particularly contribute to improving dynamic-mode AFM, in which resonance spectra with a low quality factor are used, such as noncontact mode AFM in liquid or contact resonance mode AFM. The effect of the CP can be achieved by fabricating a substrate with a thick plate beforehand.

  7. Split Malcev algebras

    Indian Academy of Sciences (India)

    We study the structure of split Malcev algebras of arbitrary dimension over an algebraically closed field of characteristic zero. We show that any such algebras is of the form M = U + ∑ j I j with U a subspace of the abelian Malcev subalgebra and any I j a well described ideal of satisfying [ I j , I k ] = 0 if ≠ .

  8. Splitting of Comets

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 1. Splitting of Comets. Utpal Mukhopadhyay. General Article Volume 7 Issue 1 January 2002 pp 11-22. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/007/01/0011-0022. Keywords. Cometary ...

  9. Diffraction-dependent spin splitting in spin Hall effect of light on reflection.

    Science.gov (United States)

    Qiu, Xiaodong; Xie, Linguo; Qiu, Jiangdong; Zhang, Zhiyou; Du, Jinglei; Gao, Fuhua

    2015-07-27

    We report on a diffraction-dependent spin splitting of the paraxial Gaussian light beams on reflection theoretically and experimentally. In the case of horizontal incident polarization, the spin splitting is proportional to the diffraction length of light beams near the Brewster angle. However, the spin splitting is nearly independent with the diffraction length for the vertical incident polarization. By means of the angular spectrum theory, we find that the diffraction-dependent spin splitting is attributed to the first order expansion term of the reflection coefficients with respect to the transverse wave-vector which is closely related to the diffraction length.

  10. Influence of Poisson's ratio variation on lateral spring constant of atomic force microscopy cantilevers

    International Nuclear Information System (INIS)

    Yeh, M.-K.; Tai, N.-Ha; Chen, B.-Y.

    2008-01-01

    Atomic force microscopy (AFM) can be used to measure the surface morphologies and the mechanical properties of nanostructures. The force acting on the AFM cantilever can be obtained by multiplying the spring constant of AFM cantilever and the corresponding deformation. To improve the accuracy of force experiments, the spring constant of AFM cantilever must be calibrated carefully. Many methods, such as theoretical equations, the finite element method, and the use of reference cantilever, were reported to obtain the spring constant of AFM cantilevers. For the cantilever made of single crystal, the Poisson's ratio varies with different cantilever-crystal angles. In this paper, the influences of Poisson's ratio variation on the lateral spring constant and axial spring constant of rectangular and V-shaped AFM cantilevers, with different tilt angles and normal forces, were investigated by the finite element analysis. When the cantilever's tilt angle is 20 deg. and the Poisson's ratio varies from 0.02 to 0.4, the finite element results show that the lateral spring constants decrease 11.75% for the rectangular cantilever with 1 μN landing force and decrease 18.60% for the V-shaped cantilever with 50 nN landing force, respectively. The influence of Poisson's ratio variation on axial spring constant is less than 3% for both rectangular and V-shaped cantilevers. As the tilt angle increases, the axial spring constants for rectangular and V-shaped cantilevers decrease substantially. The results obtained can be used to improve the accuracy of the lateral force measurement when using atomic force microscopy

  11. Split warhead simultaneous impact

    Directory of Open Access Journals (Sweden)

    Rahul Singh Dhari

    2017-12-01

    Full Text Available A projectile system is proposed to improve efficiency and effectiveness of damage done by anti-tank weapon system on its target by designing a ballistic projectile that can split into multiple warheads and engage a target at the same time. This idea has been developed in interest of saving time consumed from the process of reloading and additional number of rounds wasted on target during an attack. The proposed system is achieved in three steps: Firstly, a mathematical model is prepared using the basic equations of motion. Second, An Ejection Mechanism of proposed warhead is explained with the help of schematics. Third, a part of numerical simulation which is done using the MATLAB software. The final result shows various ranges and times when split can be effectively achieved. With the new system, impact points are increased and hence it has a better probability of hitting a target.

  12. First application of multilayer graphene cantilever for laser photoacoustic detection

    Czech Academy of Sciences Publication Activity Database

    Suchánek, Jan; Dostál, Michal; Vlasáková, T.; Janda, Pavel; Klusáčková, Monika; Kubát, Pavel; Nevrlý, V.; Bitala, P.; Civiš, Svatopluk; Zelinger, Zdeněk

    2017-01-01

    Roč. 101, APR 2017 (2017), s. 9-14 ISSN 0263-2241 R&D Projects: GA ČR(CZ) GA14-14696S; GA MŠk(CZ) LD14022 Grant - others:COST(XE) TD1105 Institutional support: RVO:61388955 Keywords : Cantilever * Multilayer graphene * Photoacoustic detection * Methanol detection Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 2.359, year: 2016

  13. Simulation Study on Material Property of Cantilever Piezoelectric Vibration Generator

    Directory of Open Access Journals (Sweden)

    Yan Zhen

    2014-06-01

    Full Text Available For increasing generating capacity of cantilever piezoelectric vibration generator with limited volume, relation between output voltage, inherent frequency and material parameter of unimorph, bimorph in series type and bimorph in parallel type piezoelectric vibration generator is analyzed respectively by mechanical model and finite element modeling. The results indicate PZT-4, PZT- 5A and PZT-5H piezoelectric materials and stainless steel, nickel alloy substrate material should be firstly chosen.

  14. First application of multilayer graphene cantilever for laser photoacoustic detection

    Czech Academy of Sciences Publication Activity Database

    Suchánek, Jan; Dostál, Michal; Vlasáková, T.; Janda, Pavel; Klusáčková, Monika; Kubát, Pavel; Nevrlý, V.; Bitala, P.; Civiš, Svatopluk; Zelinger, Zdeněk

    2017-01-01

    Roč. 101, APR 2017 (2017), s. 9-14 ISSN 0263-2241 R&D Projects: GA ČR(CZ) GA14-14696S; GA MŠk(CZ) LD14022 Institutional support: RVO:61388955 Keywords : Cantilever * Multilayer graphene * Photoacoustic detection * Methanol detection Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 2.359, year: 2016

  15. Canine extrusion with a vertical tube supported cantilever spring

    Directory of Open Access Journals (Sweden)

    U H Vijayashree

    2017-01-01

    Full Text Available Maxillary canine is the most frequently impacted tooth in the dental arch and twice common in females than in males. Treatment of impacted maxillary canine can be difficult and time consuming, depending on its position. Improper direction and magnitude of applied force can lead to increased chances of adjacent tooth resorption. This article describes about a simple cantilever spring that can be fabricated at chair side for extrusion of a bucally impacted canine.

  16. On split Lie triple systems

    Indian Academy of Sciences (India)

    We also introduced in [1] techniques of connection of roots in the framework of split Lie algebras. In the present paper we extend these techniques to the framework of split Lie triple systems so as to obtain a generalization of the results in [1]. We consider the wide class of split Lie triple systems (which contains the class of.

  17. A geometric parameter study of piezoelectric coverage on a rectangular cantilever energy harvester

    International Nuclear Information System (INIS)

    Patel, R; McWilliam, S; Popov, A A

    2011-01-01

    This paper proposes a versatile model for optimizing the performance of a rectangular cantilever beam piezoelectric energy harvester used to convert ambient vibrations into electrical energy. The developed model accounts for geometric changes to the natural frequencies, mode shapes and damping in the structure. This is achieved through the combination of finite element modelling and a distributed parameter electromechanical model, including load resistor and charging capacitor models. The model has the potential for use in investigating the influence of numerous geometric changes on harvester performance, and incorporates a model for accounting for changes in damping as the geometry changes. The model is used to investigate the effects of substrate and piezoelectric layer length, and piezoelectric layer thickness on the performance of a microscale device. Findings from a parameter study indicate the existence of an optimum sample length due to increased mechanical damping for longer beams and improved power output using thicker piezoelectric layers. In practice, harvester design is normally based around a fixed operating frequency for a particular application, and improved performance is often achieved by operating at or near resonance. To achieve unbiased comparisons between different harvester designs, parameter studies are performed by changing multiple parameters simultaneously with the natural frequency held fixed. Performance enhancements were observed using shorter piezoelectric layers as compared to the conventional design, in which the piezoelectric layer and substrate are of equal length

  18. Parameter uncertainties in the design and optimization of cantilever piezoelectric energy harvesters

    Science.gov (United States)

    Franco, V. R.; Varoto, P. S.

    2017-09-01

    A crucial issue in piezoelectric energy harvesting is the efficiency of the mechanical to electrical conversion process. Several techniques have been investigated in order to obtain a set of optimum design parameters that will lead to the best performance of the harvester in terms of electrical power generation. Once an optimum design is reached it is also important to consider uncertainties in the selected parameters that in turn can lead to loss of performance in the energy conversion process. The main goal of this paper is to perform a comprehensive discussion of the effects of multi-parameter aleatory uncertainties on the performance and design optimization of a given energy harvesting system. For that, a typical energy harvester consisting of a cantilever beam carrying a tip mass and partially covered by piezoelectric layers on top and bottom surfaces is considered. A distributed parameter electromechanical modal of the harvesting system is formulated and validated through experimental tests. First, the SQP (Sequential Quadratic Planning) optimization is employed to obtain an optimum set of parameters that will lead to best performance of the harvester. Second, once the optimum harvester configuration is found random perturbations are introduced in the key parameters and Monte Carlo simulations are performed to investigate how these uncertainties propagate and affect the performance of the device studied. Numerically simulated results indicate that small variations in some design parameters can cause a significant variation in the output electrical power, what strongly suggests that uncertainties must be accounted for in the design of beam energy harvesting systems.

  19. Cantilever Wings for Modern Aircraft: Some Aspects of Cantilever Wing Construction with Special Reference to Weight and Torsional Stiffness

    Science.gov (United States)

    Stieger, H J

    1929-01-01

    In the foregoing remarks I have made an attempt to touch on some of the structural problems met with in cantilever wings, and dealt rather fully with a certain type of single-spar construction. The experimental test wing was a first attempt to demonstrate the principles of this departure from orthodox methods. The result was a wing both torsionally stiff and of light weight - lighter than a corresponding biplane construction.

  20. Experimental confirmation of the atomic force microscope cantilever stiffness tilt correction

    Science.gov (United States)

    Gates, Richard S.

    2017-12-01

    The tilt angle (angle of repose) of an AFM cantilever relative to the surface it is interrogating affects the effective stiffness of the cantilever as it analyzes the surface. For typical AFMs and cantilevers that incline from 10° to 15° tilt, this is thought to be a 3%-7% stiffness increase correction. While the theoretical geometric analysis of this effect may have reached a consensus that it varies with cos-2 θ, there is very little experimental evidence to confirm this using AFM cantilevers. Recently, the laser Doppler vibrometry thermal calibration method utilized at NIST has demonstrated sufficient stiffness calibration accuracy, and precision to allow a definitive experimental confirmation of the particular trigonometric form of this tilt effect using a commercial microfabricated AFM cantilever specially modified to allow strongly tilted (up to 15°) effective cantilever stiffness measurements.

  1. Design Optimization of Cantilever Based MEMS Micro-accelerometer for High-g Applications

    Directory of Open Access Journals (Sweden)

    B. D. PANT

    2009-11-01

    Full Text Available Design optimization study of micro-cantilever based MEMS accelerometer is presented in this paper. The cantilever structure is dc biased with an ac signal to extract output voltage generated due to the change in capacitance. This signal modifies the behavior of the sensing element. The cantilever performance under a combined inertial and electrostatic force has been considered for estimating the dimensional dependence of cantilever sensitivity, non-linearity, off-set and critical acceleration and operating voltages. The cantilever performance has been verified using ANSYSTM Multiphysics software. Finally, a micro-accelerometer based on an array of 15 cantilevers has been designed and fabricated with a high sensitivity of 3 - 4 mV/g with a non-linearity of < 1 % for high-g (50 g applications.

  2. Using the Finite Elements Method (FEM) for Nanotechnology Education. A rectangular cantilever as a mass sensor

    Science.gov (United States)

    Aya Baquero, H.

    2015-01-01

    The Finite Element Method FEM can be used in the context of physics engineering education, particularly in nanotechnology training. Cantilevers and cantilevers arrays have been implemented as sensors within lots of applications. In the present paper, FEM was used to assess validity of basic models where cantilevers are used as mass sensors. Resonance frequency of a cantilever transversal vibration was found; this was a silicon one-side clamped cantilever. A number of minor mass elements Am was added on the cantilever's free side. Then in each case, a new resonance frequency was found; this led to obtain the Am values from shifts of resonance frequencies. Finally, those values were compared with CAD model values.

  3. Vibrating Cantilever Transducer Incorporated in Dual Diaphragms Structure for Sensing Differential Pneumatic Pressure

    OpenAIRE

    Cellatoglu, Akin; Karuppanan, Balasubramanian

    2012-01-01

    Pneumatic pressure cells with thin metallic spherical diaphragm of shallow spherical shell configuration linked with vibrating wire pickup or vibrating cantilever pickup were reported in the past. In order to enhance the sensitivity of the pressure cell this work considers dual diaphragm structure fitted with cantilever pickup. The design and development of the pressure cell with this dual diaphragm structure having cantilever pickup is presented here. The geometrical design is optimally made...

  4. The role of the cantilever in Kelvin probe force microscopy measurements

    Directory of Open Access Journals (Sweden)

    George Elias

    2011-05-01

    Full Text Available The role of the cantilever in quantitative Kelvin probe force microscopy (KPFM is rigorously analyzed. We use the boundary element method to calculate the point spread function of the measuring probe: Tip and cantilever. The calculations show that the cantilever has a very strong effect on the absolute value of the measured contact potential difference even under ultra-high vacuum conditions, and we demonstrate a good agreement between our model and KPFM measurements in ultra-high vacuum of NaCl monolayers grown on Cu(111. The effect of the oscillating cantilever shape on the KPFM resolution and sensitivity has been calculated and found to be relatively small.

  5. Environmental sensors based on micromachined cantilevers with integrated read-out

    DEFF Research Database (Denmark)

    Boisen, Anja; Thaysen, Jacob; Jensenius, Henriette

    2000-01-01

    An AFM probe with integrated piezoresistive read-out has been developed and applied as a cantilever-based environmental sensor. The probe has a built-in reference cantilever, which makes it possible to subtract background drift directly in the measurement. Moreover, the integrated read-out facili......An AFM probe with integrated piezoresistive read-out has been developed and applied as a cantilever-based environmental sensor. The probe has a built-in reference cantilever, which makes it possible to subtract background drift directly in the measurement. Moreover, the integrated read...

  6. Nonlinear Vibration of an Elastically Restrained Tapered Beam

    DEFF Research Database (Denmark)

    Karimpour, S; Ganji, S.S; Barari, Amin

    2012-01-01

    This paper presents the analytical simulation of an elastically restrained tapered cantilever beam using the energy balance method (EBM) and the iteration perturbation method (IPM). To assess the accuracy of solutions, we compare the results with the harmonic balance method (HBM). The obtained re...

  7. MTN magnet for the SPS extracted beam.

    CERN Multimedia

    CERN PhotoLab

    1976-01-01

    This type of dipole magnet was used in the extracted beam lines of the North Area. It shows an opening for three different proton beam lines: a primary extracted proton beam, split by an upstream magnetic beam splitter (see photo 7612017) into three separated beams passes through different parts of its aperture: right, left up, left down. These magnets were designed to be concrete-insulated for radiation resistance. F. Streun stands on the right.

  8. Nonlinear Dynamics of Cantilever-Sample Interactions in Atomic Force Microscopy

    Science.gov (United States)

    Cantrell, John H.; Cantrell, Sean A.

    2010-01-01

    The interaction of the cantilever tip of an atomic force microscope (AFM) with the sample surface is obtained by treating the cantilever and sample as independent systems coupled by a nonlinear force acting between the cantilever tip and a volume element of the sample surface. The volume element is subjected to a restoring force from the remainder of the sample that provides dynamical equilibrium for the combined systems. The model accounts for the positions on the cantilever of the cantilever tip, laser probe, and excitation force (if any) via a basis set of set of orthogonal functions that may be generalized to account for arbitrary cantilever shapes. The basis set is extended to include nonlinear cantilever modes. The model leads to a pair of coupled nonlinear differential equations that are solved analytically using a matrix iteration procedure. The effects of oscillatory excitation forces applied either to the cantilever or to the sample surface (or to both) are obtained from the solution set and applied to the to the assessment of phase and amplitude signals generated by various acoustic-atomic force microscope (A-AFM) modalities. The influence of bistable cantilever modes of on AFM signal generation is discussed. The effects on the cantilever-sample surface dynamics of subsurface features embedded in the sample that are perturbed by surface-generated oscillatory excitation forces and carried to the cantilever via wave propagation are accounted by the Bolef-Miller propagating wave model. Expressions pertaining to signal generation and image contrast in A-AFM are obtained and applied to amplitude modulation (intermittent contact) atomic force microscopy and resonant difference-frequency atomic force ultrasonic microscopy (RDF-AFUM). The influence of phase accumulation in A-AFM on image contrast is discussed, as is the effect of hard contact and maximum nonlinearity regimes of A-AFM operation.

  9. Flutter instability of cantilevered carbon nanotubes caused by magnetic fluid flow subjected to a longitudinal magnetic field

    Science.gov (United States)

    Sadeghi-Goughari, Moslem; Jeon, Soo; Kwon, Hyock-Ju

    2018-04-01

    CNT (Carbon nanotube)-based fluidic systems hold a great potential for emerging medical applications such as drug delivery for cancer therapy. CNTs can be used to deliver anticancer drugs into a target site under a magnetic field guidance. One of the critical issues in designing such systems is how to avoid the vibration induced by the fluid flow, which is undesirable and may even promote the structural instability. The main objective of the present research is to develop a fluid structure interaction (FSI) model to investigate the flutter instability of a cantilevered CNT induced by a magnetic fluid flow under a longitudinal magnetic field. The CNT is assumed to be embedded in a viscoelastic matrix to consider the effect of biological medium around it. To obtain a dynamical model for the system, the Navier-Stokes theory of magnetic-fluid flow is coupled to the Euler-Bernoulli beam model for CNT. The small size effects of the magnetic fluid and CNT are considered through the small scale parameters including Knudsen number (Kn) and the nonlocal parameter. Then, the extended Galerkin's method is applied to solve the FSI governing equations, and to derive the stability diagrams of the system. Results show how the magnetic properties of the fluid flow have an effect on improving the stability of the cantilevered CNT by increasing the flutter velocity.

  10. Heater-Integrated Cantilevers for Nano-Samples Thermogravimetric Analysis

    Directory of Open Access Journals (Sweden)

    Valeria Toffoli

    2013-12-01

    Full Text Available The design and characteristics of a micro-system for thermogravimetric analysis (TGA in which heater, temperature sensor and mass sensor are integrated into a single device are presented. The system consists of a suspended cantilever that incorporates a microfabricated resistor, used as both heater and thermometer. A three-dimensional finite element analysis was used to define the structure parameters. TGA sensors were fabricated by standard microlithographic techniques and tested using milli-Q water and polyurethane microcapsule. The results demonstrated that our approach provides a faster and more sensitive TGA with respect to commercial systems.

  11. Fabrication of a cantilever-based microfluidic flow meter with nL min(-1) resolution

    DEFF Research Database (Denmark)

    Noeth, Nadine-Nicole; Keller, Stephan Sylvest; Boisen, Anja

    2011-01-01

    ). With this etch the cantilever structures are under-etched before they are released by tweezers and the release yield is enhanced from 41.5% to 84.0%. In a continuous flow mode, the deflection of the cantilevers is directly proportional to the flow rate. By tuning the design of the integrated grid (hole size...

  12. Optical device comprising a cantilever and method of fabrication and use thereof

    NARCIS (Netherlands)

    Iannuzzi, Davide; Deladi, S.; Elwenspoek, Michael Curt

    2008-01-01

    The present invention provides an optical device, comprising an optical fiber and a cantilever that is arranged on an end of the optical fiber; The cantilever may be an integral part of the optical fiber, and may have a length that is substantially equal to a diameter of the optical fiber.

  13. Optical device comprising a cantilever and method of fabrication and use thereof

    NARCIS (Netherlands)

    Iannuzzi, Davide; Deladi, S.; Elwenspoek, Michael Curt

    2011-01-01

    The present invention provides an optical device, comprising an optical fiber and a cantilever that is arranged on an end of the optical fiber; The cantilever may be an integral part of the optical fiber, and may have a length that is substantially equal to a diameter of the optical fiber.

  14. Investigations on antibody binding to a micro-cantilever coated with a BAM pesticide residue

    DEFF Research Database (Denmark)

    Bache, Michael; Taboryski, Rafael Jozef; Schmid, Silvan

    2011-01-01

    -BAM antibody is measured using the CantiLab4© system from Cantion A/S with four gold-coated cantilevers and piezo resistive readout. The detection mechanism is in principle label-free, but fluorescent-marked antibodies have been used to subsequently verify the binding on the cantilever surface. The bending...

  15. Size-dependent effective Young’s modulus of silicon nitride cantilevers

    NARCIS (Netherlands)

    Babaei Gavan, K.; Westra, H.J.R.; Van der Drift, E.W.J.M.; Venstra, W.J.; Van der Zant, H.S.J.

    2009-01-01

    The effective Young’s modulus of silicon nitride cantilevers is determined for thicknesses in the range of 20–684 nm by measuring resonance frequencies from thermal noise spectra. A significant deviation from the bulk value is observed for cantilevers thinner than 150 nm. To explain the observations

  16. Determination of young's modulus of PZT-influence of cantilever orientation

    NARCIS (Netherlands)

    Nazeer, H.; Woldering, L.A.; Abelmann, Leon; Elwenspoek, Michael Curt

    Calculation of the resonance frequency of cantilevers fabricated from an elastically anisotropic material requires the use of an effective Young’s modulus. In this paper a technique to determine the appropriate effective Young’s modulus for arbitrary cantilever geometries is introduced. This

  17. A novel fabrication technique for free-hanging homogeneous polymeric cantilever waveguides

    DEFF Research Database (Denmark)

    Nordström, M.; Calleja, M.; Hübner, Jörg

    2008-01-01

    We present a novel bonding technique developed for the fabrication of a cantilever-based biosensing system with integrated optical read-out. The read-out mechanism is based on single-mode waveguides fabricated monolithically in SU-8. For optimal operation of the read-out mode, the cantilever wave...

  18. Monolithic Concrete vs Precast Concrete for the Construction of Bridge by Th Cantilever Method

    Directory of Open Access Journals (Sweden)

    Morlova Dumitru Daniel

    2015-07-01

    Full Text Available In the article "Monolithic Concrete vs Precast Concrete for the Construction of Bridges by the Cantilever Method", there are approached a number of issues that come out in the design and execution of prestressed concrete bridge structures using the cantilever method.

  19. Evaluation of bending moment and deflection of cantilever supported excavations

    Directory of Open Access Journals (Sweden)

    Seyed Hamid Yasrebi

    2017-11-01

    Full Text Available In many conditions, because of several restrictions, cantilever walls are the only way to stabilize the excavations. It is no doubt that one of the most important parameters in design of such walls is wall stiffness. Therefore, in this study, a large number of case histories are collected and the most commonly used range of wall thickness and stiffness are determined based on this database. In addition, validation of limit equilibrium method (LEM in granular soils showed that this method can only estimate bending moment of rigid walls. Therefore, for more accurate estimating, a new equation is presented for the most commonly used range of wall stiffness and various types of granular soils. Moreover, LEM based equation is replaced with a modified version. The new equation was successfully validated using 70 numerical models and results lied in range of 85% to 115% times the predicted values obtained from FEM. According to the results, in loose and very loose soils, the common cantilever walls can only stabilize the excavations with depth less than 10 m. While if depth is more than 15 m, soil type should be dense or very dense with “E” more than about 70 MPa. The results also show that the effect of wall stiffness is negligible in bending moments less than 2000 kN.m.

  20. Instability of a cantilevered flexible plate in viscous channel flow

    Science.gov (United States)

    Balint, T. S.; Lucey, A. D.

    2005-10-01

    The stability of a flexible cantilevered plate in viscous channel flow is studied as a representation of the dynamics of the human upper airway. The focus is on instability mechanisms of the soft palate (flexible plate) that cause airway blockage during sleep. We solve the Navier Stokes equations for flow with Reynolds numbers up to 1500 fully coupled with the dynamics of the plate motion solved using finite-differences. The study is 2-D and based upon linearized plate mechanics. When both upper and lower airways are open, the plate is found to lose its stability through a flutter mechanism and a critical Reynolds number exists. When one airway is closed, the plate principally loses its stability through a divergence mechanism and a critical flow speed exists. However, below the divergence-onset flow speed, flutter can exist for low levels of structural damping in the flexible plate. Our results serve to extend understanding of flow-induced instability of cantilevered flexible plates and will ultimately improve the diagnosis and treatment of upper-airway disorders.

  1. Polymeric Micro-channel-based Functionalisation System for Micro-Cantilevers

    DEFF Research Database (Denmark)

    Nordström, Maria; Gomez, Montserrat; Boisen, Anja

    2005-01-01

    A micro-channel system intended for functionalising micro-cantilevers used for biochemical detection has been designed, realised and characterised. The chip is fabricated in the resist SU-8, which is a photosensitive polymer offering a fast, cost-efficient and easy processing. Cantilevers present...... a new platform for biochemical detection with a high sensitivity. This micro-channel system is used for treating such a cantilever array with probe molecules prior to detection and it can also be used as the analysis set-up. The design of the micro-channel system provides a simple way of coating...... separate sections of a cantilever array with different probe molecules. The use of this channel system eliminates the time-consuming step of addressing each cantilever individually to obtain an array functionalised with different probe molecules. Using this micro-channel system in combination...

  2. Controlling the opto-mechanics of a cantilever in an interferometer via cavity loss

    Energy Technology Data Exchange (ETDEWEB)

    Schmidsfeld, A. von, E-mail: avonschm@uos.de; Reichling, M., E-mail: reichling@uos.de [Fachbereich Physik, Universität Osnabrück, Barbarastraße 7, 49076 Osnabrück (Germany)

    2015-09-21

    In a non-contact atomic force microscope, based on interferometric cantilever displacement detection, the optical return loss of the system is tunable via the distance between the fiber end and the cantilever. We utilize this for tuning the interferometer from a predominant Michelson to a predominant Fabry-Pérot characteristics and introduce the Fabry-Pérot enhancement factor as a quantitative measure for multibeam interference in the cavity. This experimentally easily accessible and adjustable parameter provides a control of the opto-mechanical interaction between the cavity light field and the cantilever. The quantitative assessment of the light pressure acting on the cantilever oscillating in the cavity via the frequency shift allows an in-situ measurement of the cantilever stiffness with remarkable precision.

  3. Fabrication and evaluation of a graphene oxide-based cantilever-type flow-meter for subsonic gas flow rate measurement

    Science.gov (United States)

    Hamdollahi, Hassan; Rahbar-Shahrouzi, Javad

    2018-05-01

    In this paper, a cantilever-type flow meter was fabricated to measure the rate of air flow in turbulent subsonic regimes such as purged gases. In the fabrication process, a piezoresistive material was coated on an interdigitated electric board as a substrate. The piezoresistive layer was a blend of latex as the polymeric matrix and graphene oxide as the sensing nanomaterial agent, which was reduced by solvothermal reduction method. The piezoresistive blend was dip-coated on a substrate with dotted pattern and was then reduced at 240 °C for 1 h in every coating step. When an air flow passed over the surface of the cantilever beam, the beam was bent in the downward direction, resulting in small variations in the resistance of the piezoresistive layer and a change in the bending angle of the cantilever which were measured simultaneously. The air flow rate was acquired via calibrating electrical resistance changes by Arduino and Wheatstone bridge circuit. The blending angle of the substrate caused by the interaction between the airflow and the cantilever and recorded by the camera and image processing was ultimately compared with the simulation results. The flow meter accuracy as a percentage of full scale (% FS) was calculated to be  ±5.8%, and mean deviation was equal to 2.1 (% FS) with the appropriate response time of 0.70 s at the air flow range of 100‑240 m s‑1. Highlights • A cantilever-type flow meter was fabricated to measure the high-speed air flow rate. • The sensitive piezoresistive material was composed of GO and latex. • The dip-coating method was used to deposit the piezoresistive layer on the fiberglass substrate. • The impact of effective parameters on the performance of the flow meter was investigated. • A simulation study was performed and the results were compared with the experimental data.

  4. Modulated-splitting-ratio fiber-optic temperature sensor

    Science.gov (United States)

    Beheim, Glenn; Anthan, Donald J.; Rys, John R.; Fritsch, Klaus; Ruppe, Walter R.

    1989-06-01

    A fiber-optic temperature sensor is described that uses a small silicon beamsplitter whose splitting ratio varies as a function of temperature. A four-beam technique is used to measure the sensor's temperature-indicating splitting ratio. This referencing method provides a measurement that is largely independent of the transmission properties of the sensor's optical fiber link. A significant advantage of this sensor, relative to other fiber-optic sensors, is its high stability, which permits the fiber-optic components to be readily substituted, thereby simplifying the sensor's installation and maintenance.

  5. Evaluation of electromechanical coupling parameters of piezoelectric materials by using piezoelectric cantilever with coplanar electrode structure in quasi-stasis.

    Science.gov (United States)

    Zheng, Xuejun; Zhu, Yuankun; Liu, Xun; Liu, Jing; Zhang, Yong; Chen, Jianguo

    2014-02-01

    Based on Timoshenko beam theory, a principle model is proposed to establish the relationship between electric charge and excitation acceleration, and in quasi-stasis we apply the direct piezoelectric effect of multilayer cantilever with coplanar electrode structure to evaluate the piezoelectric strain coefficient d15 and electromechanical coupling coefficient k15. They are measured as 678 pC/N and 0.74 for the commercial piezoelectric ceramic lead zirconate titanate (PZT-51) bulk specimen and 656 pC/N and 0.63 for the lead magnesium niobate (PMN) bulk specimen, and they are in agreement with the calibration and simulation values. The maximum of relative errors is less than 4.2%, so the proposed method is reliable and convenient.

  6. Magnetic domain structure investigation of Bi: YIG-thin films by combination of AFM and cantilever-based aperture SNOM

    International Nuclear Information System (INIS)

    Vysokikh, Yu E; Shevyakov, V I; Krasnoborodko, S Yu; Shelaev, A V; Prokopov, A R

    2016-01-01

    We present the results of magnetic domain structure investigation by combination of atomic force microscopy (AFM) and scanning near-field optical microscopy (SNOM). Special hollow-pyramid AFM cantilevers with aperture was used. This combination allows us use same probe for both topography and domain structure visualization of Bi -substituted ferrite garnet films of micro- and nano-meter thickness. Samples were excited through aperture by tightly focused linearly polarized laser beam. Magneto-optical effect rotates polarization of transmitted light depend on domain orientation. Visualization of magnetic domains was performed by detecting cross polarized component of transmitted light. SNOM allows to obtain high resolution magnetic domain image and prevent sample from any disturbance by magnetic probe. Same area SNOM and MFM images are presented. (paper)

  7. Vibration attenuation and shape control of surface mounted, embedded smart beam

    Directory of Open Access Journals (Sweden)

    Vivek Rathi

    Full Text Available Active Vibration Control (AVC using smart structure is used to reduce the vibration of a system by automatic modification of the system structural response. AVC is widely used, because of its wide and broad frequency response range, low additional mass, high adaptability and good efficiency. A lot of research has been done on Finite Element (FE models for AVC based on Euler Bernoulli Beam Theory (EBT. In the present work Timoshenko Beam Theory (TBT is used to model a smart cantilever beam with surface mounted sensors / actuators. A Periodic Output Feedback (POF Controller has been designed and applied to control the first three modes of vibration of a flexible smart cantilever beam. The difficulties encountered in the usage of surface mounted piezoelectric patches in practical situations can be overcome by the use of embedded shear sensors / actuators. A mathematical model of a smart cantilever beam with embedded shear sensors and actuators is developed. A POF Controller has been designed and applied to control of vibration of a flexible smart cantilever beam and effect of actuator location on the performance of the controller is investigated. The mathematical modeling and control of a Multiple Input multiple Output (MIMO systems with two sensors and two actuators have also been considered.

  8. Split SUSY Radiates Flavor

    CERN Document Server

    Baumgart, Matthew; Zorawski, Thomas

    2014-01-01

    Radiative flavor models where the hierarchies of Standard Model (SM) fermion masses and mixings are explained via loop corrections are elegant ways to solve the SM flavor puzzle. Here we build such a model in the context of Mini-Split Supersymmetry (SUSY) where both flavor and SUSY breaking occur at a scale of 1000 TeV. This model is consistent with the observed Higgs mass, unification, and WIMP dark matter. The high scale allows large flavor mixing among the sfermions, which provides part of the mechanism for radiative flavor generation. In the deep UV, all flavors are treated democratically, but at the SUSY breaking scale, the third, second, and first generation Yukawa couplings are generated at tree level, one loop, and two loops, respectively. Save for one, all the dimensionless parameters in the theory are O(1), with the exception being a modest and technically natural tuning that explains both the smallness of the bottom Yukawa coupling and the largeness of the Cabibbo angle.

  9. How rivers split

    Science.gov (United States)

    Seybold, H. F.; Yi, R.; Devauchelle, O.; Petroff, A.; Rothman, D.

    2012-12-01

    River networks have fascinated mankind for centuries. They exhibit a striking geometry with similar shapes repeating on all scales. Yet, how these networks form and create these geometries remains elusive. Recently we have shown that channels fed by subsurface flow split at a characteristic angle of 2π/5 unambiguously consistent with our field measurements in a seepage network on the Florida Panhandle (Fig.1). Our theory is based only on the simple hypothesis that the channels grow in the direction at which the ground water enters the spring and classical solutions of subsurface hydrology. Here we apply our analysis to the ramification of large drainage basins and extend our theory to include slope effects. Using high resolution stream networks from the National Hydrography Dataset (NHD), we scrutinize our hypothesis in arbitrary channel networks and investigate the branching angle dependence on Horton-Strahler order and the maturity of the streams.; High-resolution topographic map of valley networks incised by groundwater flow, located on the Florida Panhandle near Bristol, FL.

  10. Split supersymmetry radiates flavor

    Science.gov (United States)

    Baumgart, Matthew; Stolarski, Daniel; Zorawski, Thomas

    2014-09-01

    Radiative flavor models where the hierarchies of Standard Model (SM) fermion masses and mixings are explained via loop corrections are elegant ways to solve the SM flavor puzzle. Here we build such a model in the context of mini-split supersymmetry (SUSY) where both flavor and SUSY breaking occur at a scale of 1000 TeV. This model is consistent with the observed Higgs mass, unification, and dark matter as a weakly interacting massive particle. The high scale allows large flavor mixing among the sfermions, which provides part of the mechanism for radiative flavor generation. In the deep UV, all flavors are treated democratically, but at the SUSY-breaking scale, the third, second, and first generation Yukawa couplings are generated at tree level, one loop, and two loops, respectively. Save for one, all the dimensionless parameters in the theory are O(1), with the exception being a modest and technically natural tuning that explains both the smallness of the bottom Yukawa coupling and the largeness of the Cabibbo angle.

  11. Analysis of Adaptive Fuzzy Technique for Multiple Crack Diagnosis of Faulty Beam Using Vibration Signatures

    Directory of Open Access Journals (Sweden)

    Amiya Kumar Dash

    2013-01-01

    Full Text Available This paper discusses the multicrack detection of structure using fuzzy Gaussian technique. The vibration parameters derived from the numerical methods of the cracked cantilever beam are used to set several fuzzy rules for designing the fuzzy controller used to predict the crack location and depth. Relative crack locations and relative crack depths are the output parameters from the fuzzy inference system. The method proposed in the current analysis is used to evaluate the dynamic response of cracked cantilever beam. The results of the proposed method are in good agreement with the results obtained from the developed experimental setup.

  12. Vibrational behavior of adaptive aircraft wing structures modelled as composite thin-walled beams

    Science.gov (United States)

    Song, O.; Librescu, L.; Rogers, C. A.

    1992-01-01

    The vibrational behavior of cantilevered aircraft wings modeled as thin-walled beams and incorporating piezoelectric effects is studied. Based on the converse piezoelectric effect, the system of piezoelectric actuators conveniently located on the wing yield the control of its associated vertical and lateral bending eigenfrequencies. The possibility revealed by this study enabling one to increase adaptively the eigenfrequencies of thin-walled cantilevered beams could play a significant role in the control of the dynamic response and flutter of wing and rotor blade structures.

  13. Global Locator, Local Locator, and Identifier Split (GLI-Split

    Directory of Open Access Journals (Sweden)

    Michael Menth

    2013-03-01

    Full Text Available The locator/identifier split is an approach for a new addressing and routing architecture to make routing in the core of the Internet more scalable. Based on this principle, we developed the GLI-Split framework, which separates the functionality of current IP addresses into a stable identifier and two independent locators, one for routing in the Internet core and one for edge networks. This makes routing in the Internet more stable and provides more flexibility for edge networks. GLI-Split can be incrementally deployed and it is backward-compatible with the IPv6 Internet. We describe its architecture, compare it to other approaches, present its benefits, and finally present a proof-of-concept implementation of GLI-Split.

  14. Split-Field Magnet facility upgraded

    CERN Multimedia

    CERN PhotoLab

    1977-01-01

    The Split Field Magnet (SFM) was the largest spectrometer for particles from beam-beam collisions in the ISR. It could determine particle momenta in a large solid angle, but was designed mainly for the analysis of forward travelling particles.As the magnet was working on the ISR circulating beams, its magnetic field had to be such as to restore the correct proton orbit.The SFM, therefore, produced zero field at the crossing point and fields of opposite signs upstream and downstream of it and was completed by 2 large and 2 small compensator magnets. The gradient effects were corrected by magnetic channels equipped with movable flaps. The useful magnetic field volume was 28 m3, the induction in the median plane 1.14 T, the gap heigth 1.1 m, the length 10.5 m, the weight about 1000 ton. Concerning the detectors, the SFM was the first massive application of multiwire proportional chambers (about 70000 wires) which filled the main and the large compensator magnets. In 1976 an improved programme was started with tw...

  15. Fast nanotopography imaging using a high speed cantilever with integrated heater-thermometer.

    Science.gov (United States)

    Lee, Byeonghee; Somnath, Suhas; King, William P

    2013-04-05

    This paper presents a high speed tapping cantilever with an integrated heater-thermometer for fast nanotopography imaging. The cantilever is much smaller and faster than previous heated cantilevers, with a length of 35 μm and a resonant frequency of 1.4 MHz. The mechanical response time is characterized by scanning over a backward-facing step of height 20 nm. The mechanical response time is 77 μs in air and 448 μs in water, which compares favorably to the fastest commercial cantilevers that do not have integrated heaters. The doped silicon cantilever is designed with an integrated heater that can heat and cool in about 10 μs and can operate in both air and water. We demonstrate standard laser-based topography imaging along with thermal topography imaging, when the cantilever is actuated via the piezoelectric shaker in an atomic force microscope system and when it is actuated by Lorentz forces. The cantilever can perform thermal topography imaging in tapping mode with an imaging resolution of 7 nm at a scan speed of 1.46 mm s(-1).

  16. Spring constant calibration of atomic force microscope cantilevers of arbitrary shape

    International Nuclear Information System (INIS)

    Sader, John E.; Sanelli, Julian A.; Adamson, Brian D.; Bieske, Evan J.; Monty, Jason P.; Marusic, Ivan; Wei Xingzhan; Mulvaney, Paul; Crawford, Simon A.; Friend, James R.

    2012-01-01

    The spring constant of an atomic force microscope cantilever is often needed for quantitative measurements. The calibration method of Sader et al. [Rev. Sci. Instrum. 70, 3967 (1999)] for a rectangular cantilever requires measurement of the resonant frequency and quality factor in fluid (typically air), and knowledge of its plan view dimensions. This intrinsically uses the hydrodynamic function for a cantilever of rectangular plan view geometry. Here, we present hydrodynamic functions for a series of irregular and non-rectangular atomic force microscope cantilevers that are commonly used in practice. Cantilever geometries of arrow shape, small aspect ratio rectangular, quasi-rectangular, irregular rectangular, non-ideal trapezoidal cross sections, and V-shape are all studied. This enables the spring constants of all these cantilevers to be accurately and routinely determined through measurement of their resonant frequency and quality factor in fluid (such as air). An approximate formulation of the hydrodynamic function for microcantilevers of arbitrary geometry is also proposed. Implementation of the method and its performance in the presence of uncertainties and non-idealities is discussed, together with conversion factors for the static and dynamic spring constants of these cantilevers. These results are expected to be of particular value to the design and application of micro- and nanomechanical systems in general.

  17. Anterior Cantilever Resin-Bonded Fixed Dental Prostheses: A Review of the Literature.

    Science.gov (United States)

    Mourshed, Bilal; Samran, Abdulaziz; Alfagih, Amal; Samran, Ahalm; Abdulrab, Saleem; Kern, Matthias

    2018-03-01

    This review evaluated the survival rate of single retainer anterior resin-bonded fixed dental prostheses (RBFDPs) to determine whether the choice of material affects their clinical outcome. An electronic search of the English peer-reviewed dental literature in PubMed was conducted to identify all publications reporting on cantilever RBFDPs until May 2016. Study information extraction and methodological quality assessments were accomplished by two reviewers independently. The searched keywords were as follows: "resin-bonded, single retainer, all-ceramic resin-bonded fixed dental prostheses (RBFDPs), all-ceramic RBFDPs, cantilever resin, RBFDPs, cantilever resin-bonded bridge, two units cantilevered, two-unit cantilevered, metal-ceramic cantilever, and metal-ceramic." Furthermore, the ''Related Articles'' feature of PubMed was used to identify further references of interest within the primary search. The bibliographies of the obtained references were used to identify pertinent secondary references. Review articles were also used to identify relevant articles. After the application of exclusion criteria, the definitive list of articles was screened to extract the qualitative data, and the results were analyzed. Overall 2588 articles were dedicated at the first review phase; however, only 311 studies were left after the elimination of duplicates and unrelated studies. Seventeen studies passed the second review phase. Five studies were excluded because they were follow-up studies of the same study cohort. Twelve studies were finally selected. The use of cantilever RBFDPs showed promising results and high survival rates. © 2016 by the American College of Prosthodontists.

  18. Accurate Calibration and Uncertainty Estimation of the Normal Spring Constant of Various AFM Cantilevers

    Directory of Open Access Journals (Sweden)

    Yunpeng Song

    2015-03-01

    Full Text Available Measurement of force on a micro- or nano-Newton scale is important when exploring the mechanical properties of materials in the biophysics and nanomechanical fields. The atomic force microscope (AFM is widely used in microforce measurement. The cantilever probe works as an AFM force sensor, and the spring constant of the cantilever is of great significance to the accuracy of the measurement results. This paper presents a normal spring constant calibration method with the combined use of an electromagnetic balance and a homemade AFM head. When the cantilever presses the balance, its deflection is detected through an optical lever integrated in the AFM head. Meanwhile, the corresponding bending force is recorded by the balance. Then the spring constant can be simply calculated using Hooke’s law. During the calibration, a feedback loop is applied to control the deflection of the cantilever. Errors that may affect the stability of the cantilever could be compensated rapidly. Five types of commercial cantilevers with different shapes, stiffness, and operating modes were chosen to evaluate the performance of our system. Based on the uncertainty analysis, the expanded relative standard uncertainties of the normal spring constant of most measured cantilevers are believed to be better than 2%.

  19. Split-illumination electron holography

    International Nuclear Information System (INIS)

    Tanigaki, Toshiaki; Aizawa, Shinji; Suzuki, Takahiro; Park, Hyun Soon; Inada, Yoshikatsu; Matsuda, Tsuyoshi; Taniyama, Akira; Shindo, Daisuke; Tonomura, Akira

    2012-01-01

    We developed a split-illumination electron holography that uses an electron biprism in the illuminating system and two biprisms (applicable to one biprism) in the imaging system, enabling holographic interference micrographs of regions far from the sample edge to be obtained. Using a condenser biprism, we split an electron wave into two coherent electron waves: one wave is to illuminate an observation area far from the sample edge in the sample plane and the other wave to pass through a vacuum space outside the sample. The split-illumination holography has the potential to greatly expand the breadth of applications of electron holography.

  20. Strategy Guideline: Quality Management in Existing Homes; Cantilever Floor Example

    Energy Technology Data Exchange (ETDEWEB)

    Taggart, J.; Sikora, J.; Wiehagen, J.; Wood, A.

    2011-12-01

    This guideline is designed to highlight the QA process that can be applied to any residential building retrofit activity. The cantilevered floor retrofit detailed in this guideline is included only to provide an actual retrofit example to better illustrate the QA activities being presented. The goal of existing home high performing remodeling quality management systems (HPR-QMS) is to establish practices and processes that can be used throughout any remodeling project. The research presented in this document provides a comparison of a selected retrofit activity as typically done versus that same retrofit activity approached from an integrated high performance remodeling and quality management perspective. It highlights some key quality management tools and approaches that can be adopted incrementally by a high performance remodeler for this or any high performance retrofit. This example is intended as a template and establishes a methodology that can be used to develop a portfolio of high performance remodeling strategies.

  1. Enhanced functionality of cantilever based mass sensors using higher modes and functionalized particles

    DEFF Research Database (Denmark)

    Dohn, Søren; Sandberg, Rasmus Kousholt; Svendsen, Winnie Edith

    2005-01-01

    By positioning a single gold-particle at different locations along the length axis on a cantilever based mass sensor, we have investigated the effect of mass position on the mass responsivity and compared the results to simulations. A significant improvement in quality factor and responsivity was...... was achieved by operating the cantilever in the 4th bending mode, thereby increasing the intrinsic sensitivity. It is shown that the use of higher bending modes grants a spatial resolution and thereby enhances the functionality of the cantilever based mass sensor....

  2. Air-spaced PDMS piezo-electret cantilevers for vibration energy harvesting

    Science.gov (United States)

    Kachroudi, A.; Basrour, S.; Rufer, L.; Jomni, F.

    2016-11-01

    This paper reports a design of a new prototype of air-spaced cantilevers made from a micro-structured PDMS piezo-electret material for accelerometer and energy harvesting applications. The test performed on these cantilevers in a sensor mode exhibits a stable sensitivity of 385 mV/g for a frequency ranging from 5 Hz to 200 Hz that encompass most macro-scale vibrations. In the energy harvesting mode, the cantilever generates a power of 103 nW with a load resistance of 217 MΩ.

  3. Spatial spectrograms of vibrating atomic force microscopy cantilevers coupled to sample surfaces

    International Nuclear Information System (INIS)

    Wagner, Ryan; Raman, Arvind; Proksch, Roger

    2013-01-01

    Many advanced dynamic Atomic Force Microscopy (AFM) techniques such as contact resonance, force modulation, piezoresponse force microscopy, electrochemical strain microscopy, and AFM infrared spectroscopy exploit the dynamic response of a cantilever in contact with a sample to extract local material properties. Achieving quantitative results in these techniques usually requires the assumption of a certain shape of cantilever vibration. We present a technique that allows in-situ measurements of the vibrational shape of AFM cantilevers coupled to surfaces. This technique opens up unique approaches to nanoscale material property mapping, which are not possible with single point measurements alone

  4. Mass and position determination of attached particles on cantilever based mass sensors

    DEFF Research Database (Denmark)

    Dohn, Søren; Svendsen, Winnie Edith; Boisen, Anja

    2007-01-01

    An analytical expression relating mass and position of a particle attached on a cantilever to the resulting change in cantilever resonant frequency is derived. Theoretically, the position and mass of the attached particle can be deduced by combining measured resonant frequencies of several bending...... modes. This finding is verified experimentally using a microscale cantilever with and without an attached gold bead. The resonant frequencies of several bending modes are measured as a function of the bead position. The bead mass and position calculated from the measured resonant frequencies are in good...... agreement with the expected mass and the position measured....

  5. Integrated MOSFET-Embedded-Cantilever-Based Biosensor Characteristic for Detection of Anthrax Simulant

    Energy Technology Data Exchange (ETDEWEB)

    Mostafa, Salwa [University of Tennessee, Knoxville (UTK); Lee, Ida [ORNL; Islam, Syed K [University of Tennessee, Knoxville (UTK); Eliza, Sazia A. [University of Tennessee, Knoxville (UTK); Shekhawat, Gajendra [Northwestern University, Evanston; Dravid, Vinayak [Northwestern University, Evanston; Tulip, Fahmida S [ORNL

    2011-01-01

    In this work, MOSFET-embedded cantilevers are configured as microbial sensors for detection of anthrax simulants, Bacillus thuringiensis. Anthrax simulants attached to the chemically treated gold-coated cantilever cause changes in the MOSFET drain current due to the bending of the cantilever which indicates the detection of anthrax simulant. Electrical properties of the anthrax simulant are also responsible for the change in the drain current. The test results suggest a detection range of 10 L of stimulant test solution (a suspension population of 1.3 107 colony-forming units/mL diluted in 40% ethanol and 60% deionized water) with a linear response of 31 A/ L.

  6. ISR split-field magnet

    CERN Multimedia

    CERN PhotoLab

    1975-01-01

    The experimental apparatus used at intersection 4 around the Split-Field Magnet by the CERN-Bologna Collaboration (experiment R406). The plastic scintillator telescopes are used for precise pulse-height and time-of-flight measurements.

  7. Method of orthogonally splitting imaging pose measurement

    Science.gov (United States)

    Zhao, Na; Sun, Changku; Wang, Peng; Yang, Qian; Liu, Xintong

    2018-01-01

    In order to meet the aviation's and machinery manufacturing's pose measurement need of high precision, fast speed and wide measurement range, and to resolve the contradiction between measurement range and resolution of vision sensor, this paper proposes an orthogonally splitting imaging pose measurement method. This paper designs and realizes an orthogonally splitting imaging vision sensor and establishes a pose measurement system. The vision sensor consists of one imaging lens, a beam splitter prism, cylindrical lenses and dual linear CCD. Dual linear CCD respectively acquire one dimensional image coordinate data of the target point, and two data can restore the two dimensional image coordinates of the target point. According to the characteristics of imaging system, this paper establishes the nonlinear distortion model to correct distortion. Based on cross ratio invariability, polynomial equation is established and solved by the least square fitting method. After completing distortion correction, this paper establishes the measurement mathematical model of vision sensor, and determines intrinsic parameters to calibrate. An array of feature points for calibration is built by placing a planar target in any different positions for a few times. An terative optimization method is presented to solve the parameters of model. The experimental results show that the field angle is 52 °, the focus distance is 27.40 mm, image resolution is 5185×5117 pixels, displacement measurement error is less than 0.1mm, and rotation angle measurement error is less than 0.15°. The method of orthogonally splitting imaging pose measurement can satisfy the pose measurement requirement of high precision, fast speed and wide measurement range.

  8. Operational beams for the LHC

    CERN Document Server

    Papaphilippou, Y.; Rumolo, G.; Manglunki, D.

    2014-01-01

    The variety of beams, needed to set-up in the injectors as requested in the LHC, are reviewed, in terms of priority but also performance expectations and reach during 2015. This includes the single bunch beams for machine commissioning and measurements (probe, Indiv) but also the standard physics beams with 50 ns and 25 ns bunch spacing and their high brightness variants using the Bunch Compression Merging and Splitting (BCMS) scheme. The required parameters and target performance of special beams like the doublet for electron cloud enhancement and the more exotic 8b$\\oplus$4e beam, compatible with some post-scrubbing scenarios are also described. The progress and plans for the LHC ion production beams during 2014-2015 are detailed. Highlights on the current progress of the setting up of the various beams are finally presented with special emphasis on potential performance issues across the proton and ion injector chain.

  9. Electrothermally driven high-frequency piezoresistive SiC cantilevers for dynamic atomic force microscopy

    International Nuclear Information System (INIS)

    Boubekri, R.; Cambril, E.; Couraud, L.; Bernardi, L.; Madouri, A.; Portail, M.; Chassagne, T.; Moisson, C.; Zielinski, M.; Jiao, S.; Michaud, J.-F.; Alquier, D.; Bouloc, J.; Nony, L.; Bocquet, F.; Loppacher, C.; Martrou, D.; Gauthier, S.

    2014-01-01

    Cantilevers with resonance frequency ranging from 1 MHz to 100 MHz have been developed for dynamic atomic force microscopy. These sensors are fabricated from 3C-SiC epilayers grown on Si(100) substrates by low pressure chemical vapor deposition. They use an on-chip method both for driving and sensing the displacement of the cantilever. A first gold metallic loop deposited on top of the cantilever is used to drive its oscillation by electrothermal actuation. The sensing of this oscillation is performed by monitoring the resistance of a second Au loop. This metallic piezoresistive detection method has distinct advantages relative to more common semiconductor-based schemes. The optimization, design, fabrication, and characteristics of these cantilevers are discussed

  10. Collecting optical coherence elastography depth profiles with a micromachined cantilever probe

    NARCIS (Netherlands)

    Chavan, D.C.; Mo, J.; de Groot, M.; Meijering, A.E.C.; de Boer, J.F.; Iannuzzi, D.

    2013-01-01

    We present an experimental setup that combines optical coherence elastography depth sensing with atomic force microscope indentation. The instrument relies on a miniaturized cantilever probe that compresses a sample with a small footprint force and simultaneously collects an optical coherence

  11. Use of self-actuating and self-sensing cantilevers for imaging biological samples in fluid.

    Science.gov (United States)

    Fantner, G E; Schumann, W; Barbero, R J; Deutschinger, A; Todorov, V; Gray, D S; Belcher, A M; Rangelow, I W; Youcef-Toumi, K

    2009-10-28

    In this paper, we present a detailed investigation into the suitability of atomic force microscopy (AFM) cantilevers with integrated deflection sensor and micro-actuator for imaging of soft biological samples in fluid. The Si cantilevers are actuated using a micro-heater at the bottom end of the cantilever. Sensing is achieved through p-doped resistors connected in a Wheatstone bridge. We investigated the influence of the water on the cantilever dynamics, the actuation and the sensing mechanisms, as well as the crosstalk between sensing and actuation. Successful imaging of yeast cells in water using the integrated sensor and actuator shows the potential of the combination of this actuation and sensing method. This constitutes a major step towards the automation and miniaturization required to establish AFM in routine biomedical diagnostics and in vivo applications.

  12. The Correlated Dynamics of Micron-Scale Cantilevers in a Viscous Fluid

    Science.gov (United States)

    Robbins, Brian A.

    A number of microcantilever systems of fundamental importance are explored using theoretical and numerical methods to quantify and provide physical insights into the dynamics of experimentally accessible systems that include a variety of configurations and viscous fluids. It is first shown that the correlated dynamics of both a laterally and vertically offset cantilever pair can be accurately predicted by numerical simulations. This is verified by comparing the correlated dynamics yielded by numerical simulations with experimental measurement. It is also demonstrated that in order to obtain these accurate predictions, geometric details of the cantilever must be included in the numerical simulation to directly reflect the experimental cantilever. A microrheology technique that utilizes the fluctuation-dissipation theorem is proposed. It is shown that by including the frequency dependence of the fluid damping, improvements in accuracy of the predictions of the rheological properties of the surrounding fluid are observed over current techniques. The amplitude spectrum of a 2-D cantilever in a power-law fluid is studied. The resulting amplitude spectrum yielded a curve similar to an overdamped system. It is observed that the amplitude and noise spectrum yield the same qualitative response for a 2-D cantilever in a shear-thinning, power-law fluid. The correlated dynamics of a tethered vertically offset cantilever pair is investigated. It is shown that for a range of stiffness ratios, which is the ratio of the spring constant of the tethering relative to the cantilever spring constant, the change in the correlated dynamics of a Hookean spring tethered cantilever pair can be seen in the presence of fluid coupling. The dynamics of a spring-mass tethered, vertically offset cantilever pair is qualitatively studied by simplifying the model to an array of springs and masses. The resulting study found that the correlated dynamics of the displacement of mass of the tethered

  13. Investigation of polymer derived ceramics cantilevers for application of high speed atomic force microscopy

    Science.gov (United States)

    Wu, Chia-Yun

    High speed Atomic Force Microscopy (AFM) has a wide variety of applications ranging from nanomanufacturing to biophysics. In order to have higher scanning speed of certain AFM modes, high resonant frequency cantilevers are needed; therefore, the goal of this research is to investigate using polymer derived ceramics for possible applications in making high resonant frequency AFM cantilevers using complex cross sections. The polymer derived ceramic that will be studied, is silicon carbide. Polymer derived ceramics offer a potentially more economic fabrication approach for MEMS due to their relatively low processing temperatures and ease of complex shape design. Photolithography was used to make the desired cantilever shapes with micron scale size followed by a wet etching process to release the cantilevers from the substrates. The whole manufacturing process we use borrow well-developed techniques from the semiconducting industry, and as such this project also could offer the opportunity to reduce the fabrication cost of AFM cantilevers and MEMS in general. The characteristics of silicon carbide made from the precursor polymer, SMP-10 (Starfire Systems), were studied. In order to produce high qualities of silicon carbide cantilevers, where the major concern is defects, proper process parameters needed to be determined. Films of polymer derived ceramics often have defects due to shrinkage during the conversion process. Thus control of defects was a central issue in this study. A second, related concern was preventing oxidation; the polymer derived ceramics we chose is easily oxidized during processing. Establishing an environment without oxygen in the whole process was a significant challenge in the project. The optimization of the parameters for using photolithography and wet etching process was the final and central goal of the project; well established techniques used in microfabrication were modified for use in making the cantilever in the project. The techniques

  14. Microfabricated photoplastic cantilever with integrated photoplastic/carbon based piezoresistive strain sensor

    DEFF Research Database (Denmark)

    Gammelgaard, Lauge; Rasmussen, Peter Andreas; Calleja, M.

    2006-01-01

    We present an SU-8 micrometer sized cantilever strain sensor with an integrated piezoresistor made of a conductive composite of SU-8 polymer and carbon black particles. The composite has been developed using ultrasonic mixing. Cleanroom processing of the polymer composite has been investigated...... silicon and the gauge factor of the composite material is relatively high, this polymer based strain sensor is more sensitive than a similar silicon based cantilever sensor. (c) 2006 American Institute of Physics....

  15. SEISMIC SAFETY OF THE PRECAST BALCONY CANTILEVER ELEMENTS FOR PREVENTION OF THERMAL BRIDGES

    Directory of Open Access Journals (Sweden)

    Boris Azinović

    2014-12-01

    Full Text Available In the paper the seismic response of precast balcony cantilever structural elements for prevention of thermal bridges was analysed. This solution has been developed in seismic non-prone areas with the main purpose of eliminating a thermal bridge at the point where the balcony is fixed to the building. The solution has been specially made to withstand vertical static loading, not accounting for eventual vertical seismic loads in the case of transferring the solution to more active seismic zones. This paper deals with the seismic analysis of existent precast cantilever elements exposed to vertical accelerations and has proven that some elements in the case of lifting are not sufficient from the safety point of view. The results of the main research results obtained by numerous seismic analyses can be summarized as follows: 1 the insertion of a precast load-bearing thermal insulation element increases the flexibility of RC fixed base cantilevers and therefore limits their length to 300–400 cm, 2 vertical seismic loads can result in the cantilever uplift, which means that tensile stresses could appear also at the bottom of the cross-section 3 precast elements, that appear on the Slovenian market to this day, do not have the appropriate steel reinforcement in the bottom part of the cross-section. For this reason, the possibility of damage is considerably higher for precast cantilever structural elements than for RC fixed base cantilevers. Statistically calculated probability of cantilever uplift for Ljubljana, which would result in severe damage, is relatively low (3% in the 50-year life span. However, the calculated value is greater than the maximum acceptable level of seismic risk for collapse. One of the possible solutions to prevent the negative influences of cantilever uplift is to consider the proper reinforcement also at the bottom of the precast elements' crosssection, or by other measures preventing uplift.

  16. A closed-loop system for frequency tracking of piezoresistive cantilever sensors

    Science.gov (United States)

    Wasisto, Hutomo Suryo; Zhang, Qing; Merzsch, Stephan; Waag, Andreas; Peiner, Erwin

    2013-05-01

    A closed loop circuit capable of tracking resonant frequencies for MEMS-based piezoresistive cantilever resonators is developed in this work. The proposed closed-loop system is mainly based on a phase locked loop (PLL) circuit. In order to lock onto the resonant frequency of the resonator, an actuation signal generated from a voltage-controlled oscillator (VCO) is locked to the phase of the input reference signal of the cantilever sensor. In addition to the PLL component, an instrumentation amplifier and an active low pass filter (LPF) are connected to the system for gaining the amplitude and reducing the noise of the cantilever output signals. The LPF can transform a rectangular signal into a sinusoidal signal with voltage amplitudes ranging from 5 to 10 V which are sufficient for a piezoactuator input (i.e., maintaining a large output signal of the cantilever sensor). To demonstrate the functionality of the system, a self-sensing silicon cantilever resonator with a built-in piezoresistive Wheatstone bridge is fabricated and integrated with the circuit. A piezoactuator is utilized for actuating the cantilever into resonance. Implementation of this closed loop system is used to track the resonant frequency of a silicon cantilever-based sensor resonating at 9.4 kHz under a cross-sensitivity test of ambient temperature. The changes of the resonant frequency are interpreted using a frequency counter connected to the system. From the experimental results, the temperature sensitivity and coefficient of the employed sensor are 0.3 Hz/°C and 32.8 ppm/°C, respectively. The frequency stability of the system can reach up to 0.08 Hz. The development of this system will enable real-time nanoparticle monitoring systems and provide a miniaturization of the instrumentation modules for cantilever-based nanoparticle detectors.

  17. Design of cantilever probes for Atomic Force Microscopy (AFM)

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2000-01-01

    keeping the stiffness constant. The resulting design of the beam from the latter optimization gives almost the same result as when maximizing the first eigenfrequency. Adding a restriction on the second eigenfrequency result in a significant change of the optimal design. The beam is modelled with 12 DOF...

  18. A Refined Zigzag Beam Theory for Composite and Sandwich Beams

    Science.gov (United States)

    Tessler, Alexander; Sciuva, Marco Di; Gherlone, Marco

    2009-01-01

    A new refined theory for laminated composite and sandwich beams that contains the kinematics of the Timoshenko Beam Theory as a proper baseline subset is presented. This variationally consistent theory is derived from the virtual work principle and employs a novel piecewise linear zigzag function that provides a more realistic representation of the deformation states of transverse-shear flexible beams than other similar theories. This new zigzag function is unique in that it vanishes at the top and bottom bounding surfaces of a beam. The formulation does not enforce continuity of the transverse shear stress across the beam s cross-section, yet is robust. Two major shortcomings that are inherent in the previous zigzag theories, shear-force inconsistency and difficulties in simulating clamped boundary conditions, and that have greatly limited the utility of these previous theories are discussed in detail. An approach that has successfully resolved these shortcomings is presented herein. Exact solutions for simply supported and cantilevered beams subjected to static loads are derived and the improved modelling capability of the new zigzag beam theory is demonstrated. In particular, extensive results for thick beams with highly heterogeneous material lay-ups are discussed and compared with corresponding results obtained from elasticity solutions, two other zigzag theories, and high-fidelity finite element analyses. Comparisons with the baseline Timoshenko Beam Theory are also presented. The comparisons clearly show the improved accuracy of the new, refined zigzag theory presented herein over similar existing theories. This new theory can be readily extended to plate and shell structures, and should be useful for obtaining relatively low-cost, accurate estimates of structural response needed to design an important class of high-performance aerospace structures.

  19. Text Fixture for Double Cantilever Beam (DCB) Specimens Subjected to Uneven Bending Moments

    DEFF Research Database (Denmark)

    Svenninggaard, Jon; Andreasen, Jens; Bak, Brian

    Bending Moments as a function of the phase angle ranging from mode I to mode II loading including mixed modes in-between. The test fixture utilizes an existing tensile testing machine and can subject specimens to loads up to 350 Nm. The test fixture is compact in size and designed using standard aluminium...... profiles for the main structure. The load is transferred from the test machine to the specimen through a 2 mm Dyneema rope. The rope is routed over a set of rollers that are positioned according to the specified mode mixity and phase angle. The kinematics of the test fixture has been analysed extensively...... as well as a 23 specially fabricated tool, made from two flat bars, which was fitted with strain gauges to verify that the strain field from the pure moment application. The analysis revealed negligible introductions of shear forces to the specimens....

  20. Fracture Behavior of Adhesive-Bonded Aluminum Foam with Double Cantilever Beam

    International Nuclear Information System (INIS)

    Bang, Hye-jin; Lee, Sang-kyo; Cho, Chongdu; Choi, Hae-kyu; Cho, Jae-ung

    2014-01-01

    In this study, closed-cell aluminum foam with an initial crack was investigated to produce an axial load-time graph. Using the 10-kN Landmarks of MTS Corporation, a 15-mm/min velocity of mode I shape was applied to the aluminum foam specimen using the displacement control method. ABAQUS 6.10 simulation was used to model and analyze the identical model in three dimensions under conditions identical to those of the experiment. The energy release rate was calculated on the basis of an axial load-displacement graph obtained from the experiment and a transient image of the crack length, and then an FE model was analyzed on the basis of this fracture energy condition. The relation between load and displacement was discussed; it was found that the aluminum foam deformed somewhat less than the adhesive layer owing to the difference in elastic modulus

  1. Series solution for large deflections of a cantilever beam with variable flexural rigidity

    DEFF Research Database (Denmark)

    Kimiaeifar, Amin; Lund, Erik; Thomsen, Ole Thybo

    2012-01-01

    during deformation. The governing equation of this problem is solved analytically for the first time using a new kind of analytical technique for nonlinear problems, namely the Homotopy Analysis Method (HAM). The present solution can be used for the analysis of a wide range of loads, material...

  2. Analytical modelling and extraction of the modal behaviour of a cantilever beam in fluid interaction

    Czech Academy of Sciences Publication Activity Database

    Gorman, D. G.; Trendafilova, I.; Mulholland, A.J.; Horáček, Jaromír

    2007-01-01

    Roč. 308, - (2007), s. 231-245 ISSN 0022-460X R&D Projects: GA AV ČR IAA200760613 Institutional research plan: CEZ:AV0Z20760514 Keywords : fluid-structure interaction * vibroacoustic * vibrations Subject RIV: BI - Acoustics Impact factor: 1.024, year: 2007

  3. Modeling and Analysis of a Bimorph PZT Cantilever Beam Based Micropower Generator

    Directory of Open Access Journals (Sweden)

    Jyoti AJITSARIA

    2009-06-01

    Full Text Available Recent developments in miniaturized sensors, digital processors and wireless communication systems have many desirable applications. The realization of these applications however, is limited by the lack of a similarly sized power source. One method of power harvesting is the use of piezoelectric materials (PZT, which form transducers that are able to interchange electrical energy and mechanical vibration. Many proposed power generation systems employ a piezoelectric component to convert the mechanical energy to electrical energy. In this paper, a formulation of mathematical model is developed that predicts the power conversion for a device that contains a piezoelectric component. Analysis is also done with AC/DC power conversion using a bridge rectifier circuit. Finally, the verification of the models is performed experimentally and comparison has been made with the simulation results. The comparison of simulation results coincide with experimental data quite well.

  4. A single nano cantilever as a reprogrammable universal logic gate

    International Nuclear Information System (INIS)

    Chappanda, K N; Ilyas, S; Kazmi, S N R; Younis, M I; Holguin-Lerma, J; Batra, N M; Costa, P M F J

    2017-01-01

    The current transistor-based computing circuits use multiple interconnected transistors to realize a single Boolean logic gate. This leads to higher power requirements and delayed computing. Transistors are not suitable for applications in harsh environments and require complicated thermal management systems due to excessive heat dissipation. Also, transistor circuits lack the ability to dynamically reconfigure their functionality in real time, which is desirable for enhanced computing capability. Further, the miniaturization of transistors to improve computational power is reaching its ultimate physical limits. As a step towards overcoming the limitations of transistor-based computing, here we demonstrate a reprogrammable universal Boolean logic gate based on a nanoelectromechanical cantilever (NC) oscillator. The fundamental XOR, AND, NOR, OR and NOT logic gates are condensed in a single NC, thereby reducing electrical interconnects between devices. The device is dynamically switchable between any logic gates at the same drive frequency without the need for any change in the circuit. It is demonstrated to operate at elevated temperatures minimizing the need for thermal management systems. It has a tunable bandwidth of 5 MHz enabling parallel and dynamically reconfigurable logic device for enhanced computing. (paper)

  5. A single nano cantilever as a reprogrammable universal logic gate

    KAUST Repository

    Chappanda, K. N.

    2017-02-24

    The current transistor-based computing circuits use multiple interconnected transistors to realize a single Boolean logic gate. This leads to higher power requirements and delayed computing. Transistors are not suitable for applications in harsh environments and require complicated thermal management systems due to excessive heat dissipation. Also, transistor circuits lack the ability to dynamically reconfigure their functionality in real time, which is desirable for enhanced computing capability. Further, the miniaturization of transistors to improve computational power is reaching its ultimate physical limits. As a step towards overcoming the limitations of transistor-based computing, here we demonstrate a reprogrammable universal Boolean logic gate based on a nanoelectromechanical cantilever (NC) oscillator. The fundamental XOR, AND, NOR, OR and NOT logic gates are condensed in a single NC, thereby reducing electrical interconnects between devices. The device is dynamically switchable between any logic gates at the same drive frequency without the need for any change in the circuit. It is demonstrated to operate at elevated temperatures minimizing the need for thermal management systems. It has a tunable bandwidth of 5 MHz enabling parallel and dynamically reconfigurable logic device for enhanced computing.

  6. Vibration induced sliding: theory and experiment for a beam with a spring-loaded mass

    DEFF Research Database (Denmark)

    Miranda, Erik; Thomsen, Jon Juel

    1998-01-01

    , and contributes to a further understanding of this nonlinear phenomenon. A mathematical model is set up to describe vibration induced sliding for a base-excited cantilever beam with a spring-loaded pointmass. Approximations simplify the model into two nonlinear ordinary differential equations, describing motions...

  7. Fabrication of Cantilevered Tip-on-Aperture Probe for Enhancing Resolution of Scanning Near-Field Optical Microscopy System

    Science.gov (United States)

    Chang, Won-Seok; Jeong, Mun Seok; Kim, Dae-Chul; Kim, Jeongyong

    2007-08-01

    The scanning near-field optical microscopy (SNOM) system achieves a resolution beyond the diffraction limit of the conventional optical microscopy system by subwavelength aperture probe scanning. The problem is that the light throughput decreases very markedly with decreasing aperture diameter. Apertureless scanning near-field optical microscopes obtain a much better resolution by concentrating light field near the tip apex. However, far-field illumination by a focused laser beam generates a large background scattering signal. Both disadvantages are overcome using the tip-on-aperture (TOA) approach presented in previous works. In this study, the fabrication of a cantilevered tip for SNOM and scanning force microscopy (SFM) has been described. The nano-probes are batch-fabricated on a silicon wafer. The Si3N4 has excellent optical transparent characteristics, higher Young’s modulus and yield strength so that it should provide a better probe for SNOM and SFM. For this purpose, a Si3N4 thin film was deposited using low-pressure chemical vapor deposition (LPCVD). To form the aperture and TOA in the probe, we applied focused ion beam (FIB) machining at the end of the sharpened tip. For verification of the efficiency of the micromachined TOA probes, numerical analysis using the finite-difference time domain (FDTD) analysis and experimental measurement using an inverted microscope based the SNOM system were performed.

  8. Splitting strings on integrable backgrounds

    International Nuclear Information System (INIS)

    Vicedo, Benoit

    2011-05-01

    We use integrability to construct the general classical splitting string solution on R x S 3 . Namely, given any incoming string solution satisfying a necessary self-intersection property at some given instant in time, we use the integrability of the worldsheet σ-model to construct the pair of outgoing strings resulting from a split. The solution for each outgoing string is expressed recursively through a sequence of dressing transformations, the parameters of which are determined by the solutions to Birkhoff factorization problems in an appropriate real form of the loop group of SL 2 (C). (orig.)

  9. Checking the split beam technique (SPLIT) for dynamic IMRT using EPID dosimetry

    International Nuclear Information System (INIS)

    Richart, J.; Perez-Calatayud, J.; Granero, D.; Ballester, F.; Santos, M.; Rodriguez, S.; Navarro, M. A.; Pujades, M. C.; Camacho, C.

    2011-01-01

    The purpose of our work is to develop a tool to: 1) to analyze the correct connection between the two fields, 2) study the effect of gravity and analyze the impact of possible mismatches and 3) to show that the gamma evaluation to do with the lump sum for each flow field instead of the individual sub creep.

  10. The influence of refractive index change and initial bending of cantilevers on the optical lever readout method

    DEFF Research Database (Denmark)

    Dohn, Søren; Greve, Anders; Svendsen, Winnie Edith

    2010-01-01

    It has been speculated that the initial bending of cantilevers has a major influence on the detector signal in a cantilever-based sensor using the optical lever readout method. We have investigated theoretically as well as experimentally the changes induced in the detector signal when the optical...... lever technique is used to monitor a cantilever with initial bending during changes in the refractive index of the surrounding media. We find that for changes in refractive index as small as 10−4 the detector signal is highly dependent on the initial bending of the cantilever. The findings are validated...

  11. Split supersymmetry in brane models

    Indian Academy of Sciences (India)

    Type-I string theory in the presence of internal magnetic fields provides a concrete realization of split supersymmetry. To lowest order, gauginos are massless while squarks and sleptons are superheavy. For weak magnetic fields, the correct Standard Model spectrum guarantees gauge coupling unification with sin2 W ...

  12. VBSCan Split 2017 Workshop Summary

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Christoph Falk; et al.

    2018-01-12

    This document summarises the talks and discussions happened during the VBSCan Split17 workshop, the first general meeting of the VBSCan COST Action network. This collaboration is aiming at a consistent and coordinated study of vector-boson scattering from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.

  13. Split supersymmetry in brane models

    Indian Academy of Sciences (India)

    journal of. November 2006 physics pp. 793–802. Split supersymmetry in brane models. IGNATIOS ANTONIADIS∗. Department of Physics, CERN-Theory Division, 1211 Geneva 23, Switzerland. E-mail: Ignatios. ... that LEP data favor the unification of the three SM gauge couplings are smoking guns for the presence of new ...

  14. Water splitting by cooperative catalysis

    NARCIS (Netherlands)

    Hetterscheid, D.G.H.; van der Vlugt, J.I.; de Bruin, B.; Reek, J.N.H.

    2009-01-01

    A mononuclear Ru complex is shown to efficiently split water into H2 and O2 in consecutive steps through a heat- and light-driven process (see picture). Thermally driven H2 formation involves the aid of a non-innocent ligand scaffold, while dioxygen is generated by initial photochemically induced

  15. On split Lie triple systems

    Indian Academy of Sciences (India)

    Lie triple system; system of roots; root space; split Lie algebra; structure theory. 1. Introduction and previous definitions. Throughout this paper, Lie triple systems T are considered of arbitrary dimension and over an arbitrary field K. It is worth to mention that, unless otherwise stated, there is not any restriction on dim Tα or {k ...

  16. On split Lie triple systems

    Indian Academy of Sciences (India)

    The key tool in this job is the notion of connection of roots in the framework of split Lie triple systems. Author Affiliations. Antonio J Calderón Martín1. Departamento de Matemáticas, Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain. Dates. Manuscript received: 25 January 2008. Proceedings – Mathematical Sciences.

  17. The split coaxial linac structure and its RF modes

    International Nuclear Information System (INIS)

    Mueller, R.W.

    1989-01-01

    The Split Coaxial Cavity structure has been invented and applied for the first time in the heavy-ion RFQ linac MAXILAC of GSI. It has an ideally flat RF voltage distribution and a good power economy. From another standpoint, it is a member of the small family of linac structures where the two modes, the wanted one and the unflatness mode, are clearly and strictly separable. The unflatness or ''Q Line'' mode is analyzed in more detail in this paper. It is necessary for the understanding of the interaction of the beam with the cavity, possible beam instabilities resulting from it, and for curing these instabilities with the chance of obtaining improved beams. (orig.)

  18. MicroCantilever (MC) based nanomechanical sensor for detection of molecular interactions

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Kyung [Iowa State Univ., Ames, IA (United States)

    2011-01-01

    Specific aims of this study are to investigate the mechanism governing surface stress generation associated with chemical or molecular binding on functionalized microcantilevers. Formation of affinity complexes on cantilever surfaces leads to charge redistribution, configurational change and steric hindrance between neighboring molecules resulting in surface stress change and measureable cantilever deformation. A novel interferometry technique employing two adjacent micromachined cantilevers (a sensing/reference pair) was utilized to measure the cantilever deformation. The sensing principle is that binding/reaction of specific chemical or biological species on the sensing cantilever transduces to mechanical deformation. The differential bending of the sensing cantilever respect to the reference cantilever ensures that measured response is insensitive to environmental disturbances. As a proof of principle for the measurement technique, surface stress changes associated with: self-assembly of alkanethiol, hybridization of ssDNA, and the formation of cocaine-aptamer complexes were measured. Dissociation constant (Kd) for each molecular reaction was utilized to estimate the surface coverage of affinity complexes. In the cases of DNA hybridization and cocaine-aptamer binding, measured surface stress was found to be dependent on the surface coverage of the affinity complexes. In order to achieve a better sensitivity for DNA hybridization, immobilization of receptor molecules was modified to enhance the deformation of underlying surface. Single-stranded DNA (ssDNA) strands with thiol-modification on both 3-foot and 5-foot ends were immobilized on the gold surface such that both ends are attached to the gold surface. Immobilization condition was controlled to obtain similar receptor density as single-thiolated DNA strands. Hybridization of double-thiolated DNA strands leads to an almost two orders of magnitude increase in cantilever deformation. In both DNA

  19. Low-temperature measurements of 32nm-thick N-type piezoresistive cantilevers

    Science.gov (United States)

    Tewary, Anuranjita; Bartsch, M. S.; Kenny, T. W.

    2002-03-01

    Advances in the field of Magnetic Resonance Force Microscopy (MRFM) are demanding the development of increasingly sensitive cantilevers. Recently, piezoresistive sensing has become an progressively viable alternative to optical detection methods as the sensitivity and resolution of piezoresistive cantilevers has dramatically improved. Harley demonstrated single crystal cantilevers 900A in thickness capable of resolving 8.6fN on a 1kHz bandwidth[1]. More recently, Liang reported 700A piezoresistive cantilevers with resolution of 1.6fN on the same bandwidth[2]. This work presents the latest developments in the fabrication of ultrathin single-crystal silicon piezoresistive cantilvers. Levers 320A thick have been successfully fabricated and released, and we believe that with further process refinement, they will continue the performance trends established by Harley and Liang. We will present our measurements of the temperature dependence on the gage factor and focus on the feasibility of using piezoresistive cantilevers for MRFM. [1]Harley JA, Kenny TW, APPLIED PHYSICS LETTERS v. 75(#2) pp. 289-291 JUL 12, 1999. [2]Liang, Y. PhD Thesis, Stanford University, 2001. We would like to thank NSF Goali Program, Grant No. CMS-997-1414-001 for their support.

  20. Cantilever contribution to the total electrostatic force measured with the atomic force microscope

    International Nuclear Information System (INIS)

    Guriyanova, Svetlana; Golovko, Dmytro S; Bonaccurso, Elmar

    2010-01-01

    The atomic force microscope (AFM) is a powerful tool for surface imaging at the nanometer scale and surface force measurements in the piconewton range. Among long-range surface forces, the electrostatic forces play a predominant role. They originate if the electric potentials of the substrate and of the tip of the AFM cantilever are different. A quantitative interpretation of the AFM signal is often difficult because it depends in a complicated fashion on the cantilever–tip–surface geometry. Since the electrostatic interaction is a long-range interaction, the cantilever, which is many microns from the surface, contributes to the total electrostatic force along with the tip. Here we present results of the electrostatic interaction between a conducting flat surface and horizontal or tilted cantilevers, with and without tips, at various distances from the surface. As addressed in a previous work, we show that the contribution of the cantilever to the overall force cannot be neglected. Based on a predictive model and on 3D confocal measurements, we discuss the influence of the tilting angle of the cantilever

  1. Assembled Cantilever Fiber Touch Trigger Probe for Three-Dimensional Measurement of Microstructures

    Directory of Open Access Journals (Sweden)

    Limin Zou

    2017-11-01

    Full Text Available In this paper, an assembled cantilever fiber touch trigger probe was developed for three-dimensional measurements of clear microstructures. The probe consists of a shaft assembled vertically to an optical fiber cantilever and a probing sphere located at the free end of the shaft. The laser is emitted from the free end of the fiber cantilever and converges on the photosensitive surface of the camera through the lens. The position shift of the light spot centroid was used to detect the performance of the optical fiber cantilever, which changed dramatically when the probing sphere touched the objects being measured. Experimental results indicated that the sensing system has sensitivities of 3.32 pixels/μm, 1.35 pixels/μm, and 7.38 pixels/μm in the x, y, and z directions, respectively, and resolutions of 10 nm, 30 nm, and 5 nm were achieved in the x, y, and z, respectively. An experiment on micro slit measurement was performed to verify the high aspect ratio measurement capability of the assembled cantilever fiber (ACF probe and to calibrate the effective two-point diameter of the probing sphere. The two-point probe sphere diameter was found to be 174.634 μm with a standard uncertainly of 0.045 μm.

  2. Research on fiber-optic cantilever-enhanced photoacoustic spectroscopy for trace gas detection

    Science.gov (United States)

    Chen, Ke; Zhou, Xinlei; Gong, Zhenfeng; Yu, Shaochen; Qu, Chao; Guo, Min; Yu, Qingxu

    2018-01-01

    We demonstrate a new scheme of cantilever-enhanced photoacoustic spectroscopy, combining a sensitivity-improved fiber-optic cantilever acoustic sensor with a tunable high-power fiber laser, for trace gas detection. The Fabry-Perot interferometer based cantilever acoustic sensor has advantages such as high sensitivity, small size, easy to install and immune to electromagnetic. Tunable erbium-doped fiber ring laser with an erbium-doped fiber amplifier is used as the light source for acoustic excitation. In order to improve the sensitivity for photoacoustic signal detection, a first-order longitudinal resonant photoacoustic cell with the resonant frequency of 1624 Hz and a large size cantilever with the first resonant frequency of 1687 Hz are designed. The size of the cantilever is 2.1 mm×1 mm, and the thickness is 10 μm. With the wavelength modulation spectrum and second-harmonic detection methods, trace ammonia (NH3) has been measured. The gas detection limits (signal-to-noise ratio = 1) near the wavelength of 1522.5 nm is achieved to be 3 ppb.

  3. Acceleration tests of the INS 25.5-MHz split coaxial RFQ

    International Nuclear Information System (INIS)

    Arai, S.; Imanishi, A.; Morimoto, T.; Tojyo, E.; Tokuda, N.; Shibuya, S.

    1991-05-01

    The INS 25.5-MHz split coaxial RFQ, a linac that accelerates ions with a charge-to-mass ratio greater than 1/30 from 1 to 45.4 keV/u, is now undergoing acceleration tests with a beam of molecular nitrogen (N 2 + ) ions. Results so far obtained show that the RFQ operates in accordance with the design. Presented are preliminary results on the beam performance: emittances of the in- and output beams, output energy and its spread, and beam transmission. (author)

  4. A simple X-ray source of two orthogonal beams for small samples imaging

    Science.gov (United States)

    Hrdý, J.

    2018-04-01

    A simple method for simultaneous imaging of small samples by two orthogonal beams is proposed. The method is based on one channel-cut crystal which is oriented such that the beam is diffracted on two crystallographic planes simultaneously. These planes are symmetrically inclined to the crystal surface. The beams are three times diffracted. After the first diffraction the beam is split. After the second diffraction the split beams become parallel. Finally, after the third diffraction the beams become convergent and may be used for imaging. The corresponding angular relations to obtain orthogonal beams are derived.

  5. Interferometric optical fiber microcantilever beam biosensor

    Science.gov (United States)

    Wavering, Thomas A.; Meller, Scott A.; Evans, Mishell K.; Pennington, Charles; Jones, Mark E.; VanTassell, Roger; Murphy, Kent A.; Velander, William H.; Valdes, E.

    2000-12-01

    With the proliferation of biological weapons, the outbreak of food poisoning occurrences, and the spread of antibiotic resistant strains of pathogenic bacteria, the demand has arisen for portable systems capable of rapid, specific, and quantitative target detection. The ability to detect minute quantities of targets will provide the means to quickly assess a health hazardous situation so that the appropriate response can be orchestrated. Conventional test results generally require hours or even several days to be reported, and there is no change for real-time feedback. An interferometric optical fiber microcantilever beam biosensor has successfully demonstrated real time detection of target molecules. The microcantilever biosensor effectively combines advanced technology from silicon micromachining, optical fiber sensor, and biochemistry to create a novel detection device. This approach utilizes affinity coatings on micromachiend cantilever beams to attract target molecules. The presence of the target molecule causes bending in the cantilever beam, which is monitored using an optical displacement system. Dose-response trials have shown measured responses at nanogram/ml concentrations of target molecules. Sensitivity is expected to extend from the nanogram to the picogram range of total captured mass as the microcantilever sensors are optimized.

  6. Stability of split Stirling refrigerators

    International Nuclear Information System (INIS)

    Waele, A T A M de; Liang, W

    2009-01-01

    In many thermal systems spontaneous mechanical oscillations are generated under the influence of large temperature gradients. Well-known examples are Taconis oscillations in liquid-helium cryostats and oscillations in thermoacoustic systems. In split Stirling refrigerators the compressor and the cold finger are connected by a flexible tube. The displacer in the cold head is suspended by a spring. Its motion is pneumatically driven by the pressure oscillations generated by the compressor. In this paper we give the basic dynamic equations of split Stirling refrigerators and investigate the possibility of spontaneous mechanical oscillations if a large temperature gradient develops in the cold finger, e.g. during or after cool down. These oscillations would be superimposed on the pressure oscillations of the compressor and could ruin the cooler performance.

  7. Active vibration control of flexible cantilever plates using piezoelectric materials and artificial neural networks

    Science.gov (United States)

    Abdeljaber, Osama; Avci, Onur; Inman, Daniel J.

    2016-02-01

    The study presented in this paper introduces a new intelligent methodology to mitigate the vibration response of flexible cantilever plates. The use of the piezoelectric sensor/actuator pairs for active control of plates is discussed. An intelligent neural network based controller is designed to control the optimal voltage applied on the piezoelectric patches. The control technique utilizes a neurocontroller along with a Kalman Filter to compute the appropriate actuator command. The neurocontroller is trained based on an algorithm that incorporates a set of emulator neural networks which are also trained to predict the future response of the cantilever plate. Then, the neurocontroller is evaluated by comparing the uncontrolled and controlled responses under several types of dynamic excitations. It is observed that the neurocontroller reduced the vibration response of the flexible cantilever plate significantly; the results demonstrated the success and robustness of the neurocontroller independent of the type and distribution of the excitation force.

  8. Design and Simulation of A Novel Piezoelectric AlN-Si Cantilever Gyroscope

    Directory of Open Access Journals (Sweden)

    Jian Yang

    2018-02-01

    Full Text Available A novel design of piezoelectric aluminum nitride (AlN-Si composite cantilever gyroscope is proposed in this paper. The cantilever is stimulated to oscillate in plane by two inverse voltages which are applied on the two paralleled drive electrodes, respectively. The whole working principles are deduced, which based on the piezoelectric equation and elastic vibration equation. In this work, a cantilever gyroscope has been simulated and optimized by COMSOL Multiphysics 5.2a. The drive mode frequency is 87.422 kHz, and the sense mode frequency is 87.414 kHz. The theoretical sensitivity of this gyroscope is 0.145 pm/◦/s. This gyroscope has a small size and simple structure. It will be a better choice for the consumer electronics.

  9. Highly sensitive polymer-based cantilever-sensors for DNA detection

    International Nuclear Information System (INIS)

    Calleja, M.; Nordstroem, M.; Alvarez, M.; Tamayo, J.; Lechuga, L.M.; Boisen, A.

    2005-01-01

    We present a technology for the fabrication of cantilever arrays aimed to develop an integrated biosensor microsystem. The fabrication process is based on spin coating of the photosensitive polymer and near-ultraviolet exposure. Arrays of up to 33 microcantilevers are fabricated in the novel polymer material SU-8. The low Young's modulus of the polymer, 40 times lower than that of silicon, enables to improve the sensitivity of the sensor device for target detection. The mechanical properties of SU-8 cantilevers, such as spring constant, resonant frequency and quality factor are characterized as a function of the dimensions and the medium. The devices have been tested for measurement of the adsorption of single stranded DNA and subsequent interstitial adsorption of lateral spacer molecules. We demonstrate that sensitivity is enhanced by a factor of six compared to that of commercial silicon nitride cantilevers

  10. Lateral force microscope calibration using a modified atomic force microscope cantilever

    International Nuclear Information System (INIS)

    Reitsma, M. G.

    2007-01-01

    A proof-of-concept study is presented for a prototype atomic force microscope (AFM) cantilever and associated calibration procedure that provide a path for quantitative friction measurement using a lateral force microscope (LFM). The calibration procedure is based on the method proposed by Feiler et al. [Rev. Sci. Instrum. 71, 2746 (2000)] but allows for calibration and friction measurements to be carried out in situ and with greater precision. The modified AFM cantilever is equipped with lateral lever arms that facilitate the application of normal and lateral forces, comparable to those acting in a typical LFM friction experiment. The technique allows the user to select acceptable precision via a potentially unlimited number of calibration measurements across the full working range of the LFM photodetector. A microfabricated version of the cantilever would be compatible with typical commercial AFM instrumentation and allow for common AFM techniques such as topography imaging and other surface force measurements to be performed

  11. Nano-Workbench: A Combined Hollow AFM Cantilever and Robotic Manipulator

    Directory of Open Access Journals (Sweden)

    Héctor Hugo Pérez Garza

    2015-05-01

    Full Text Available To manipulate liquid matter at the nanometer scale, we have developed a robotic assembly equipped with a hollow atomic force microscope (AFM cantilever that can handle femtolitre volumes of liquid. The assembly consists of four independent robots, each sugar cube sized with four degrees of freedom. All robots are placed on a single platform around the sample forming a nano-workbench (NWB. Each robot can travel the entire platform and has a minimum position resolution of 5 nm both in-plane and out-of-plane. The cantilever chip was glued to the robotic arm. Dispensing was done by the capillarity between the substrate and the cantilever tip, and was monitored visually through a microscope. To evaluate the performance of the NWB, we have performed three experiments: clamping of graphene with epoxy, mixing of femtolitre volume droplets to synthesize gold nanoparticles and accurately dispense electrolyte liquid for a nanobattery.

  12. Fabrication of thin SU-8 cantilevers: initial bending, release and time stability

    DEFF Research Database (Denmark)

    Keller, Stephan Urs; Haefliger, D.; Boisen, Anja

    2010-01-01

    , the rotational deformation at the clamping point allowed a qualitative assessment of the device release from the fluorocarbon-coated substrate. The change of these parameters during several months of storage at ambient temperature was investigated in detail. The introduction of a long hard bake in an oven after...... development of the thin SU-8 film resulted in reduced cantilever bending due to removal of residual stress gradients. Further, improved time-stability of the devices was achieved due to the enhanced cross-linking of the polymer. A post-exposure bake at a temperature T-PEB = 50 degrees C followed by a hard...... bake at T-HB = 90 degrees C proved to be optimal to ensure low cantilever bending and low rotational deformation due to excellent device release and low change of these properties with time. With the optimized process, the reproducible fabrication of arrays with 2 mu m thick cantilevers with a length...

  13. A DVD-ROM based high-throughput cantilever sensing platform

    DEFF Research Database (Denmark)

    Bosco, Filippo

    the four different sensors. The platform was developed specifically for cantilever sensor applications Preliminary tests on Raman-based device integration has been carried out. The inclusion of the other two sensing techniques is currently under development. This thesis reports on the demonstration...... and mechanics from a DVD player to handle liquid samples and to read-out cantilever deflection and resonant frequency. In a few minutes, several liquid samples can be analyzed in parallel, measuring over several hundreds of individual cantilevers. Three generations of systems have been developed and tested......This thesis has been written as a partial fulfillment of the requirements for obtaining the PhD degree at DTU Nanotech. The project has been carried out at the Technical University of Denmark (DTU) at the department of Micro- and Nanotechnology, in the three-years period between November 2008...

  14. Geometrical Applications of Split Octonions

    Directory of Open Access Journals (Sweden)

    Merab Gogberashvili

    2015-01-01

    Full Text Available It is shown that physical signals and space-time intervals modeled on split-octonion geometry naturally exhibit properties from conventional (3 + 1-theory (e.g., number of dimensions, existence of maximal velocities, Heisenberg uncertainty, and particle generations. This paper demonstrates these properties using an explicit representation of the automorphisms on split-octonions, the noncompact form of the exceptional Lie group G2. This group generates specific rotations of (3 + 4-vector parts of split octonions with three extra time-like coordinates and in infinitesimal limit imitates standard Poincare transformations. In this picture translations are represented by noncompact Lorentz-type rotations towards the extra time-like coordinates. It is shown how the G2 algebra’s chirality yields an intrinsic left-right asymmetry of a certain 3-vector (spin, as well as a parity violating effect on light emitted by a moving quantum system. Elementary particles are connected with the special elements of the algebra which nullify octonionic intervals. Then the zero-norm conditions lead to free particle Lagrangians, which allow virtual trajectories also and exhibit the appearance of spatial horizons governing by mass parameters.

  15. 7 CFR 51.2002 - Split shell.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Split shell. 51.2002 Section 51.2002 Agriculture... Standards for Grades of Filberts in the Shell 1 Definitions § 51.2002 Split shell. Split shell means a shell... of the shell, measured in the direction of the crack. ...

  16. SU-8 cantilevers for bio/chemical sensing; Fabrication, characterisation and development of novel read-out methods

    DEFF Research Database (Denmark)

    Nordström, M.; Keller, Stephan Urs; Lillemose, Michael

    2008-01-01

    Here, we present the activities within our research group over the last five years with cantilevers fabricated in the polymer SU-8. We believe that SU-8 is an interesting polymer for fabrication of cantilevers for bio/chemical sensing due to its simple processing and low Young's modulus. We show...

  17. Influence of silicon orientation and cantilever undercut on the determination of the Young’s modulus of thin films

    NARCIS (Netherlands)

    Nazeer, H.; Woldering, L.A.; Abelmann, Leon; Nguyen, Duc Minh; Rijnders, Augustinus J.H.M.; Elwenspoek, Michael Curt

    The Young’s modulus of thin films can be determined by deposition on a micronsized Si cantilever and measuring the resonance frequency before and after deposition. The accuracy of the method depends strongly on the initial determination of the mechanical properties and dimensions of the cantilever.

  18. Influence of silicon orientation and cantilever undercut on the determination of Young's modulus of pulsed laser deposited PZT

    NARCIS (Netherlands)

    Nazeer, H.; Woldering, L.A.; Abelmann, Leon; Nguyen, Duc Minh; Rijnders, Augustinus J.H.M.; Elwenspoek, Michael Curt

    In this work we show for the first time that the effective in-plane Young’s modulus of PbZr0.52Ti0.48O3 (PZT) thin films, deposited by pulsed laser deposition (PLD) on dedicated single crystal silicon cantilevers, is independent of the in-plane orientation of cantilevers.

  19. Measurements on hydrophobic and hydrophilic surfaces using a porous gamma alumina nanoparticle aggregate mounted on Atomic Force Microscopy cantilevers

    NARCIS (Netherlands)

    Das, Theerthankar; Becker, Thomas; Nair, Balagopal N.

    2010-01-01

    Atomic Force Microscopy (AFM) measurements are extensively used for a detailed understanding of molecular and surface forces. In this study, we present a technique for measuring such forces, using an AFM cantilever attached with a porous gamma alumina nanoparticle aggregate. The modified cantilever

  20. Experimental determination of mode correction factors for thermal method spring constant calibration of AFM cantilevers using laser Doppler vibrometry.

    Science.gov (United States)

    Gates, Richard S; Osborn, William A; Pratt, Jon R

    2013-06-28

    Mode correction factors (MCFs) represent a significant adjustment to the spring constant values measured using the thermal cantilever calibration method. Usually, the ideal factor of 0.971 for a tipless rectangular cantilever is used, which adjusts the value by 3% for the first flexural mode. An experimental method for determining MCFs has been developed that relies on measuring the areas under the first few resonance peaks for the flexural mode type. Using this method, it has been shown that MCFs for the first flexural mode of commercially available atomic force microscope cantilevers actually vary from 0.95 to 1.0, depending on the shape and end mass of the cantilever. Triangular shaped cantilevers tend to lower MCFs with tipless versions providing the lowest values. Added masses (including tips) tend to increase the first flexural mode's MCF to higher values with large colloid probes at the high extreme. Using this understanding and applying it to the recently developed laser Doppler vibrometry thermal calibration method it is now possible to achieve very accurate and precise cantilever spring constant calibrations (uncertainties close to ±1%) with commonly available commercial cantilevers such as tipped rectangular and triangular cantilevers, and colloid probes.

  1. A Compliant Bistable Mechanism Design Incorporating Elastica Buckling Beam Theory and Pseudo-Rigid-Body Model

    DEFF Research Database (Denmark)

    Sönmez, Ümit; Tutum, Cem Celal

    2008-01-01

    In this work, a new compliant bistable mechanism design is introduced. The combined use of pseudo-rigid-body model (PRBM) and the Elastica buckling theory is presented for the first time to analyze the new design. This mechanism consists of the large deflecting straight beams, buckling beams......, and a slider. The kinematic analysis of this new mechanism is studied, using nonlinear Elastica buckling beam theory, the PRBM of a large deflecting cantilever beam, the vector loop closure equations, and numerically solving nonlinear algebraic equations. A design method of the bistable mechanism...

  2. Effect of loose spring skirt mounting position on vibration damping in a multi segment hanging cantilever

    International Nuclear Information System (INIS)

    Nazeer, M.M.; Khan, A.F.; Shah, R.H; Afzal, M.; Ahmed, N.

    2001-01-01

    The loose spring skirt clearance is the major factor effecting the damping and amplitude control of randomly excited vibrations in a vertically hanging cantilever. However, the spring's mounting position also has an important role to play. In this work, the results of computational model as well as that of experimental set-up for various spring mounting positions having optimum annular clearance between skirted member and the skirt are presented and their vibration damping response is analyzed. It is observed that lower is the mounting position, the better is the damping and its maximum value is attained when the bottom end of spring skirt and the hanging cantilever are mutually flushed. (author)

  3. Design optimization and fatigue testing of an electronically-driven mechanically-resonant cantilever spring mechanism

    International Nuclear Information System (INIS)

    Kheng, Lim Boon; Kean, Koay Loke; Gitano-Briggs, Horizon

    2010-01-01

    A light scanning device consisting of an electronically-driven mechanically-resonant cantilever spring-mirror system has been developed for innovative lighting applications. The repeated flexing of the cantilever spring during operation can lead to premature fatigue failure. A model was created to optimize the spring design. The optimized spring design can reduce stress by approximately one-third from the initial design. Fatigue testing showed that the optimized spring design can operate continuously for over 1 month without failure. Analysis of failures indicates surface cracks near the root of the spring are responsible for the failures.

  4. Fiber Bragg grating sensor based on cantilever structure embedded in polymer 3D printed material

    Science.gov (United States)

    Lima, Rita; Tavares, R.; Silva, S. O.; Abreu, P.; Restivo, Maria T.; Frazão, O.

    2017-04-01

    A cantilever structure in 3D printed based on a fiber Bragg grating (FBG) sensor embedded in polymer material is proposed. The FBG sensor was embedded in 3D printed coating and was tested under three physical parameters: displacement, temperature and vibration. The sensor was tested in displacement in two different regions of the cantilever, namely, on its midpoint and end point. The maximum displacement sensitivity achieved was (3 +/- 0.1) pm/mm for end point displacement, and a temperature sensitivity of (30 +/- 1) pm/°C was also attained. In the case of vibration measurements it was possible to obtain a 10.23Hz-low frequency oscillation.

  5. Fully additive manufacture of a polymer cantilever with an embedded functional layer

    Science.gov (United States)

    Kanazawa, Shusuke; Kusaka, Yasuyuki; Horii, Yoshinori; Ushijima, Hirobumi

    2018-03-01

    In this paper, we report on an efficient and unique printing-based process for fabricating a cantilever structure with an embedded functional layer. The process is used to form a micro suspended structure via the one-batch transfer of stacked layers from a dummy substrate. The mechanism of the transfer process is clearly explained by the order of adhesion strengths of all interfaces. As a demonstration, a strain gauge which consisted of a polymer cantilever with an embedded conductive wire was successfully fabricated. It is expected that the proposed process will widely contribute to the efficient manufacture of useful sensors and actuators.

  6. Integrated Cantilever-Based Flow Sensors with Tunable Sensitivity for In-Line Monitoring of Flow Fluctuations in Microfluidic Systems

    Directory of Open Access Journals (Sweden)

    Nadine Noeth

    2013-12-01

    Full Text Available For devices such as bio-/chemical sensors in microfluidic systems, flow fluctuations result in noise in the sensor output. Here, we demonstrate in-line monitoring of flow fluctuations with a cantilever-like sensor integrated in a microfluidic channel. The cantilevers are fabricated in different materials (SU-8 and SiN and with different thicknesses. The integration of arrays of holes with different hole size and number of holes allows the modification of device sensitivity, theoretical detection limit and measurement range. For an average flow in the microliter range, the cantilever deflection is directly proportional to the flow rate fluctuations in the microfluidic channel. The SiN cantilevers show a detection limit below 1 nL/min and the thinnest SU-8 cantilevers a detection limit below 5 nL/min. Finally, the sensor is applied for in-line monitoring of flow fluctuations generated by external pumps connected to the microfluidic system.

  7. Integrated cantilever-based flow sensors with tunable sensitivity for in-line monitoring of flow fluctuations in microfluidic systems

    DEFF Research Database (Denmark)

    Noeth, Nadine-Nicole; Keller, Stephan Sylvest; Boisen, Anja

    2014-01-01

    For devices such as bio-/chemical sensors in microfluidic systems, flow fluctuations result in noise in the sensor output. Here, we demonstrate in-line monitoring of flow fluctuations with a cantilever-like sensor integrated in a microfluidic channel. The cantilevers are fabricated in different...... materials (SU-8 and SiN) and with different thicknesses. The integration of arrays of holes with different hole size and number of holes allows the modification of device sensitivity, theoretical detection limit and measurement range. For an average flow in the microliter range, the cantilever deflection...... is directly proportional to the flow rate fluctuations in the microfluidic channel. The SiN cantilevers show a detection limit below 1 nL/min and the thinnest SU-8 cantilevers a detection limit below 5 nL/min. Finally, the sensor is applied for in-line monitoring of flow fluctuations generated by external...

  8. Effect of cantilever length and alloy framework on the stress distribution in peri-implant area of cantilevered implant-supported fixed partial dentures

    Directory of Open Access Journals (Sweden)

    Valdey SUEDAM

    2016-04-01

    Full Text Available ABSTRACT Because many mechanical variables are present in the oral cavity, the proper load transfer between the prosthesis and the bone is important for treatment planning and for the longevity of the implant-supported fixed partial denture. Objectives To verify the stress generated on the peri-implant area of cantilevered implant-supported fixed partial dentures and the potential effects of such variable. Material and Methods A U-shaped polyurethane model simulating the mandibular bone containing two implants (Ø 3.75 mm was used. Six groups were formed according to the alloy’s framework (CoCr or PdAg and the point of load application (5 mm, 10 mm and 15 mm of cantilever arm. A 300 N load was applied in pre-determined reference points. The tension generated on the mesial, lingual, distal and buccal sides of the peri-implant regions was assessed using strain gauges. Results Two-way ANOVA and Tukey statistical tests were applied showing significant differences (p<0.05 between the groups. Pearson correlation test (p<0.05 was applied showing positive correlations between the increase of the cantilever arm and the deformation of the peri-implant area. Conclusions This report demonstrated the CoCr alloy shows larger compression values compared to the PdAg alloy for the same distances of cantilever. The point of load application influences the deformation on the peri-implant area, increasing in accordance with the increase of the lever arm.

  9. Damage Identification of Beam with Breathing Crack under Fractal Dimension

    Science.gov (United States)

    Zhao, Ying; Ren, Yi Chun

    2018-03-01

    Damage identification has been more urgent in engineering, especially beam structure which is often damaged by ambient excitation. It is based on time-frequency domain analysis of beam with breathing crack under fractal dimension in this paper. An equivalent cantilever beam model is constructed. The stiffness cosine model with time as parameter is used to simulate the opening and closing process of crack. The most widely used box dimension in fractal dimension is selected to calculate and analyze the displacement response of beam structure. The results show that the changes of box dimensional of beam structure displacement response can determine whether there is damage or not and identify the damage degree intuitively. It is more practical for damage identification in actual engineering.

  10. Innovative wedge axe in making split firewood

    International Nuclear Information System (INIS)

    Mutikainen, A.

    1998-01-01

    Interteam Oy, a company located in Espoo, has developed a new method for making split firewood. The tools on which the patented System Logmatic are based are wedge axe and cylindrical splitting-carrying frame. The equipment costs about 495 FIM. The block of wood to be split is placed inside the upright carrying frame and split in a series of splitting actions using the innovative wedge axe. The finished split firewood remains in the carrying frame, which (as its name indicates) also serves as the means for carrying the firewood. This innovative wedge-axe method was compared with the conventional splitting of wood using an axe (Fiskars -handy 1400 splitting axe costing about 200 FIM) in a study conducted at TTS-Institute. There were eight test subjects involved in the study. In the case of the wedge-axe method, handling of the blocks to be split and of the finished firewood was a little quicker, but in actual splitting it was a little slower than the conventional axe method. The average productivity of splitting the wood and of the work stages related to it was about 0.4 m 3 per effective hour in both methods. The methods were also equivalent of one another in terms of the load imposed by the work when measured in terms of the heart rate. As regards work safety, the wedge-axe method was superior to the conventional method, but the continuous striking action and jolting transmitted to the arms were unpleasant (orig.)

  11. Ionic vibration induced transparency and Autler-Townes splitting

    Science.gov (United States)

    Shao, Wenjun; Wang, Fei; Feng, Xun-Li; Oh, C. H.

    2017-04-01

    In this work, the absorption spectrum of a two-level ion in a linear Paul trap is investigated, the ion is supposed to be driven by two orthogonal laser beams, the one along the axial of the trap acts as the control light beam, the other as probe beam. When the frequency of the control laser is tuned to the first red sideband of the ionic transition, the coupling between the internal states of the ion and vibrational mode turns out to be a Jaynes-Cummings (JC) Hamiltonian, which together with the coupling between the probe beam and the two-level ion constructs a Λ -type three-level structure. In this case the transparency window may appear in the absorption spectrum of the probe light, which is induced by the ionic vibration and is very similar to the cavity induced transparency (Rice and Brecha 1996 Opt. Commun. 126 230-5). On the other hand, when the frequency of the control laser is tuned to the first blue sideband of the ionic transition, the two-level ion and vibrational mode are governed by an anti-Jaynes-Cummings (anti-JC) Hamiltonian, the total system including the probe beam forms a V-type three-level structure. And the Autler-Townes splitting in the absorption spectrum is found.

  12. Multiple bunch-splitting in the PS results and plans

    CERN Document Server

    Garoby, R

    2001-01-01

    The nominal longitudinal characteristics of the PS proton beam for the LHC were attained during the year 2000, using a sequence of triple- and double-splittings to divide each PS Booster (PSB) bunch into 12. This method minimizes longitudinal emittance blow-up and preserves a gap, free of particles, in the bunch train. Some of the ideas for alternative bunch trains have also been tested. The performance achieved is described and the sources of limitations are discussed together with the foreseen improvements.

  13. Finite Element Study on Performance of Piezoelectric Bimorph Cantilevers Using Porous/Ceramic 0-3 Polymer Composites

    Science.gov (United States)

    Kiran, Raj; Kumar, Anuruddh; Chauhan, Vishal S.; Kumar, Rajeev; Vaish, Rahul

    2018-01-01

    Finite element analysis of 0-3 composites made of piezoceramic particles and pores embedded in polyvinylidene difluoride (PVDF) has been carried out. The representative volume element (RVE) approach was used to calculate the effective elastic and piezoelectric properties of the periodic isotropic 0-3 piezoelectric composites. It was observed that the elastic and piezoelectric properties increased with the volume fraction of {K}_{0.475} {Na}_{0.475} {Li}_{0.05} ( {{Nb}_{0.92} {Ta}_{0.05} {Sb}_{0.03} } ){O}3 (KNLNTS) particles but decreased for the porous composites. These effective properties were further used to analyze the potential use of such bimorph cantilever beams in sensing and energy harvesting applications. Sensing voltage continuously increased for KNLNTS filled composites while for porous materials it increased up to 15% volume fraction porosity and then decreased. The same trend was also observed for the power produced by the harvester. However, the sensing voltage and power produced by harvesters made of porous composites were lower than for harvesters made of pure PVDF.

  14. Optimization of Natural Frequencies and Sound Power of Beams Using Functionally Graded Material

    Directory of Open Access Journals (Sweden)

    Nabeel T. Alshabatat

    2014-01-01

    Full Text Available This paper presents a design method to optimize the material distribution of functionally graded beams with respect to some vibration and acoustic properties. The change of the material distribution through the beam length alters the stiffness and the mass of the beam. This can be used to alter a specific beam natural frequency. It can also be used to reduce the sound power radiated from the vibrating beam. Two novel volume fraction laws are used to describe the material volume distributions through the length of the FGM beam. The proposed method couples the finite element method (for the modal and harmonic analysis, Lumped Parameter Model (for calculating the power of sound radiation, and an optimization technique based on Genetic Algorithm. As a demonstration of this technique, the optimization procedure is applied to maximize the fundamental frequency of FGM cantilever and clamped beams and to minimize the sound radiation from vibrating clamped FGM beam at a specific frequency.

  15. Parallel BLAST on split databases.

    Science.gov (United States)

    Mathog, David R

    2003-09-22

    BLAST programs often run on large SMP machines where multiple threads can work simultaneously and there is enough memory to cache the databases between program runs. A group of programs is described which allows comparable performance to be achieved with a Beowulf configuration in which no node has enough memory to cache a database but the cluster as an aggregate does. To achieve this result, databases are split into equal sized pieces and stored locally on each node. Each query is run on all nodes in parallel and the resultant BLAST output files from all nodes merged to yield the final output. Source code is available from ftp://saf.bio.caltech.edu/

  16. Coherent beam-beam effects

    International Nuclear Information System (INIS)

    Chao, A.W.

    1992-01-01

    There are two physical pictures that describe the beam-beam interaction in a storage ring collider: The weak-strong and the strong-strong pictures. Both pictures play a role in determining the beam-beam behavior. This review addresses only the strong-strong picture. The corresponding beam dynamical effects are referred to as the coherent beam-beam effects. Some basic knowledge of the weak-strong picture is assumed. To be specific, two beams of opposite charges are considered. (orig.)

  17. Temperature effects in Au piezoresistors integrated in SU-8 cantilever chips

    DEFF Research Database (Denmark)

    Johansson, Alicia; Hansen, Ole; Hales, Jan Harry

    2006-01-01

    to binding of biomolecules on the surface of the cantilever. Here we present the characterization of the chip with respect to temperature changes in the surrounding environment. Furthermore, self-heating of the piezoresistors due to the applied voltage over the resistors is investigated including...

  18. Self-aligned cantilever positioning for on-substrate measurements using DVD pickup head

    DEFF Research Database (Denmark)

    Bosco, Filippo; Hwu, E. T.; Keller, Stephan Urs

    2010-01-01

    In this paper, we present a novel approach for measuring the resonant frequency of cantilevers fabricated in polymeric materials. We re-designed the use of a commercial DVD-ROM pickup head and combine it with a glass-polymer substrate in order to obtain a light and portable device to measure...

  19. Investigation of cleaning and regeneration methods for reliable construction of DNA cantilever biosensors

    DEFF Research Database (Denmark)

    Quan, Xueling; Yi, Sun; Heiskanen, Arto

    to clean and regenerate the sensing surface of cantilever biosensors. Perchloric acid potential sweep, potassium hydroxide-hydrogen peroxide, and piranha cleaning are investigated here. Peak-current potential differences from cyclic voltammetry, X-ray photo-electron spectroscopy and fluorescence detection...

  20. Highly Sensitive Polymer-based Cantilever-sensors for DNA Detection

    DEFF Research Database (Denmark)

    Gomez, Montserrat; Nordström, Maria; Alvarez, M.

    2005-01-01

    polymer material SU-8. The low Young's modulus of the polymer, 40 times lower than that of silicon, enables to improve the sensitivity of the sensor device for target detection. The mechanical properties of SU-8 cantilevers, such as spring constant, resonant frequency and quality factor are characterized...

  1. Nano-Workbench : A Combined Hollow AFM Cantilever and Robotic Manipulator

    NARCIS (Netherlands)

    Pérez Garza, H.; Ghatkesar, M.K.; Basak, S.; Löthman, P.; Staufer, U.

    2015-01-01

    To manipulate liquid matter at the nanometer scale, we have developed a robotic assembly equipped with a hollow atomic force microscope (AFM) cantilever that can handle femtolitre volumes of liquid. The assembly consists of four independent robots, each sugar cube sized with four degrees of freedom.

  2. Multifrequency Piezoelectric Energy Harvester Based on Polygon-Shaped Cantilever Array

    Directory of Open Access Journals (Sweden)

    Dalius Mažeika

    2018-01-01

    Full Text Available This paper focuses on numerical and experimental investigations of a novel design piezoelectric energy harvester. Investigated harvester is based on polygon-shaped cantilever array and employs multifrequency operating principle. It consists of eight cantilevers with irregular design of cross-sectional area. Cantilevers are connected to each other by specific angle to form polygon-shaped structure. Moreover, seven seismic masses with additional lever arms are added in order to create additional rotation moment. Numerical investigation showed that piezoelectric polygon-shaped energy harvester has five natural frequencies in the frequency range from 10 Hz to 240 Hz, where the first and the second bending modes of the cantilevers are dominating. Maximum output voltage density and energy density equal to 50.03 mV/mm3 and 604 μJ/mm3, respectively, were obtained during numerical simulation. Prototype of piezoelectric harvester was made and experimental investigation was performed. Experimental measurements of the electrical characteristics showed that maximum output voltage density, energy density, and output power are 37.5 mV/mm3, 815.16 μJ/mm3, and 65.24 μW, respectively.

  3. Development and characterization of electrochemical cantilever sensor for bio/chemical sensing applications

    DEFF Research Database (Denmark)

    Quan, Xueling; Fischer, Lee MacKenzie; Boisen, Anja

    2011-01-01

    We report the improvements made to our previously developed electrochemical cantilever (EC) sensor, where nanoporous gold material is employed as working electrodes in microcantilever arrays, while combined counter-reference electrodes are integrated on the chip. For a surface stress change of 1m...

  4. Superresolution beams

    CSIR Research Space (South Africa)

    Ngcobo, S

    2011-11-01

    Full Text Available zones capable of introducing a phase shift of zero or p on the alternately out of phase rings of the TEMp0 beams into a unified phase and then focusing the rectified beam to generate a high resolution beam which has a Gaussian beam intensity distribution...

  5. Experimental Determination of Bending Resonances of Millimeter Size PVF2 Cantilevers

    Directory of Open Access Journals (Sweden)

    David F. Thompson

    2003-07-01

    Full Text Available The polymer piezoelectric polvinylidene fluoride has found widespread use in sensors and actuators. The bending mode of piezoelectricity offers very high sensitivities and low mechanical input impedance, but has not been studied in as much detail for sensor applications. We report the dynamic electromechanical properties of millimeter size cantilevers made from electroded films of PVF2. All devices tested had a single polymer layer. Several resonances are found below 1 kHz and the experimentally observed resonance frequency dependence on cantilever thickness and length are seen to agree well with published models which take the properties of the electrodes into account. It is found that bending resonances are also modulated by the width of the cantilever. Therefore, though the length and thickness control the resonance frequency most strongly, the actual realized value can be fine-tuned by changing cantilever width and the electrode material and its thickness. Further, all resonances display high piezoelectric coupling coefficients (keff, ranging between 0.2 - 0.35. The data presented here will be extremely useful in the design of sensors and actuators for a number of applications, since the combination of millimeter size scales and high piezoelectric sensitivities in the low audio range can be realized with this marriage of polymeric materials and cantilever geometries. Such an array of sensors can be used in cochlear implant applications, and when integrated with a resonance interrogation circuit can be used for the detection of low frequency vibrations of large structures. If appropriate mass/elasticity sensitive layers are coated on the electrodes, such a sensor can be used for the detection of a wide range of chemicals and biochemicals.

  6. Cu(OH2 and CuO Nanorod Synthesis on Piezoresistive Cantilevers for the Selective Detection of Nitrogen Dioxide

    Directory of Open Access Journals (Sweden)

    Laurent Schlur

    2018-04-01

    Full Text Available Self-controlled active oscillating microcantilevers with a piezoresistive readout are very promising sensitive sensors, despite their small surface. In order to increase this surface and consequently their sensitivity, we nanostructured them with copper hydroxide (Cu(OH2 or with copper oxide (CuO nanorods. The Cu(OH2 rods were grown, on a homogeneous copper layer previously evaporated on the top of the cantilever. The CuO nanorods were further obtained by the annealing of the copper hydroxide nanostructures. Then, these copper based nanorods were used to detect several molecules vapors. The results showed no chemical affinity (no formation of a chemical bond between the CuO cantilevers and the tested molecules. The cantilever with Cu(OH2 nanorods is selective to nitrogen dioxide (NO2 in presence of humidity. Indeed, among all the tested analytes, copper hydroxide has only an affinity with NO2. Despite the absence of affinity, the cantilevers could even so condensate explosives (1,3,5-trinitro-1,3,5-triazinane (RDX and pentaerythritol tetranitrate (PETN on their surface when the cantilever temperature was lower than the explosives source, allowing their detection. We proved that in condensation conditions, the cantilever surface material has no importance and that the nanostructuration is useless because a raw silicon cantilever detects as well as the nanostructured ones.

  7. Algebraic techniques for diagonalization of a split quaternion matrix in split quaternionic mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Tongsong, E-mail: jiangtongsong@sina.com [Department of Mathematics, Linyi University, Linyi, Shandong 276005 (China); Department of Mathematics, Heze University, Heze, Shandong 274015 (China); Jiang, Ziwu; Zhang, Zhaozhong [Department of Mathematics, Linyi University, Linyi, Shandong 276005 (China)

    2015-08-15

    In the study of the relation between complexified classical and non-Hermitian quantum mechanics, physicists found that there are links to quaternionic and split quaternionic mechanics, and this leads to the possibility of employing algebraic techniques of split quaternions to tackle some problems in complexified classical and quantum mechanics. This paper, by means of real representation of a split quaternion matrix, studies the problem of diagonalization of a split quaternion matrix and gives algebraic techniques for diagonalization of split quaternion matrices in split quaternionic mechanics.

  8. Testing PVLAS axions with resonant photon splitting

    CERN Document Server

    Gabrielli, E; Gabrielli, Emidio; Giovannini, Massimo

    2007-01-01

    The photon splitting gamma -> gamma gamma in a time-independent and inhomogeneous magnetized background is considered when neutral and ultralight spin-0 particles are coupled to two-photons. Depending on the inhomogeneity scale of the external field, resonant photon splitting can occur. If an optical laser crosses a magnetic field of few Tesla with typical inhomogeneity scale of the order of the meter, a potentially observable rate of photon splittings is expected for the PVLAS range of couplings and masses.

  9. Additive operator-difference schemes splitting schemes

    CERN Document Server

    Vabishchevich, Petr N

    2013-01-01

    Applied mathematical modeling isconcerned with solving unsteady problems. This bookshows how toconstruct additive difference schemes to solve approximately unsteady multi-dimensional problems for PDEs. Two classes of schemes are highlighted: methods of splitting with respect to spatial variables (alternating direction methods) and schemes of splitting into physical processes. Also regionally additive schemes (domain decomposition methods)and unconditionally stable additive schemes of multi-component splitting are considered for evolutionary equations of first and second order as well as for sy

  10. Iterative Splitting Methods for Differential Equations

    CERN Document Server

    Geiser, Juergen

    2011-01-01

    Iterative Splitting Methods for Differential Equations explains how to solve evolution equations via novel iterative-based splitting methods that efficiently use computational and memory resources. It focuses on systems of parabolic and hyperbolic equations, including convection-diffusion-reaction equations, heat equations, and wave equations. In the theoretical part of the book, the author discusses the main theorems and results of the stability and consistency analysis for ordinary differential equations. He then presents extensions of the iterative splitting methods to partial differential

  11. Electromechanical model of a resonating nano-cantilever-based sensor for high-resolution and high-sensitivity mass detection

    DEFF Research Database (Denmark)

    Abadal, G.; Davis, Zachary James; Helbo, Bjarne

    2001-01-01

    A simple linear electromechanical model for an electrostatically driven resonating cantilever is derived. The model has been developed in order to determine dynamic quantities such as the capacitive current flowing through the cantilever-driver system at the resonance frequency, and it allows us...... to calculate static magnitudes such as position and voltage of collapse or the voltage versus deflection characteristic. The model is used to demonstrate the theoretical sensitivity on the attogram scale of a mass sensor based on a nanometre-scale cantilever, and to analyse the effect of an extra feedback loop...

  12. Spin Splitting in Different Semiconductor Quantum Wells

    International Nuclear Information System (INIS)

    Hao Yafei

    2012-01-01

    We theoretically investigate the spin splitting in four undoped asymmetric quantum wells in the absence of external electric field and magnetic field. The quantum well geometry dependence of spin splitting is studied with the Rashba and the Dresselhaus spin-orbit coupling included. The results show that the structure of quantum well plays an important role in spin splitting. The Rashba and the Dresselhaus spin splitting in four asymmetric quantum wells are quite different. The origin of the distinction is discussed in this work. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  13. Beam-beam and impedance

    CERN Document Server

    White, S.

    2014-07-17

    As two counter-rotating beams interact they can give rise to coherent dipole modes. Under the influence of impedance these coherent beam-beam modes can couple to higher order head-tail modes and lead to strong instabilities. A fully self-consistent approach including beam-beam and impedance was used to characterize this new coupled mode instability and study possible cures such as a transverse damper and high chromaticity.

  14. Dark matter from split seesaw

    International Nuclear Information System (INIS)

    Kusenko, Alexander; Takahashi, Fuminobu; Yanagida, Tsutomu T.

    2010-01-01

    The seesaw mechanism in models with extra dimensions is shown to be generically consistent with a broad range of Majorana masses. The resulting democracy of scales implies that the seesaw mechanism can naturally explain the smallness of neutrino masses for an arbitrarily small right-handed neutrino mass. If the scales of the seesaw parameters are split, with two right-handed neutrinos at a high scale and one at a keV scale, one can explain the matter-antimatter asymmetry of the universe, as well as dark matter. The dark matter candidate, a sterile right-handed neutrino with mass of several keV, can account for the observed pulsar velocities and for the recent data from Chandra X-ray Observatory, which suggest the existence of a 5 keV sterile right-handed neutrino.

  15. Gauge mediated mini-split

    Science.gov (United States)

    Cohen, Timothy; Craig, Nathaniel; Knapen, Simon

    2016-03-01

    We propose a simple model of split supersymmetry from gauge mediation. This model features gauginos that are parametrically a loop factor lighter than scalars, accommodates a Higgs boson mass of 125 GeV, and incorporates a simple solution to the μ- b μ problem. The gaugino mass suppression can be understood as resulting from collective symmetry breaking. Imposing collider bounds on μ and requiring viable electroweak symmetry breaking implies small a-terms and small tan β — the stop mass ranges from 105 to 108 GeV. In contrast with models with anomaly + gravity mediation (which also predict a one-loop loop suppression for gaugino masses), our gauge mediated scenario predicts aligned squark masses and a gravitino LSP. Gluinos, electroweakinos and Higgsinos can be accessible at the LHC and/or future colliders for a wide region of the allowed parameter space.

  16. Minimal Doubling and Point Splitting

    Energy Technology Data Exchange (ETDEWEB)

    Creutz, M.

    2010-06-14

    Minimally-doubled chiral fermions have the unusual property of a single local field creating two fermionic species. Spreading the field over hypercubes allows construction of combinations that isolate specific modes. Combining these fields into bilinears produces meson fields of specific quantum numbers. Minimally-doubled fermion actions present the possibility of fast simulations while maintaining one exact chiral symmetry. They do, however, introduce some peculiar aspects. An explicit breaking of hyper-cubic symmetry allows additional counter-terms to appear in the renormalization. While a single field creates two different species, spreading this field over nearby sites allows isolation of specific states and the construction of physical meson operators. Finally, lattice artifacts break isospin and give two of the three pseudoscalar mesons an additional contribution to their mass. Depending on the sign of this mass splitting, one can either have a traditional Goldstone pseudoscalar meson or a parity breaking Aoki-like phase.

  17. Gauge mediated mini-split

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, Timothy [Institute of Theoretical Science, University of Oregon,Eugene, OR 97403 (United States); Craig, Nathaniel [Department of Physics, University of California,Santa Barbara, CA 93106 (United States); Knapen, Simon [Berkeley Center for Theoretical Physics,University of California, Berkeley, CA 94720 (United States); Theoretical Physics Group,Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2016-03-15

    We propose a simple model of split supersymmetry from gauge mediation. This model features gauginos that are parametrically a loop factor lighter than scalars, accommodates a Higgs boson mass of 125 GeV, and incorporates a simple solution to the μ−b{sub μ} problem. The gaugino mass suppression can be understood as resulting from collective symmetry breaking. Imposing collider bounds on μ and requiring viable electroweak symmetry breaking implies small a-terms and small tan β — the stop mass ranges from 10{sup 5} to 10{sup 8} GeV. In contrast with models with anomaly + gravity mediation (which also predict a one-loop loop suppression for gaugino masses), our gauge mediated scenario predicts aligned squark masses and a gravitino LSP. Gluinos, electroweakinos and Higgsinos can be accessible at the LHC and/or future colliders for a wide region of the allowed parameter space.

  18. Active vibration control of a piezoelectric beam using PID controller: Experimental study

    Directory of Open Access Journals (Sweden)

    Najeeb ur Rahman

    Full Text Available Vibration suppression of smart beams using the piezoelectric patch structure is presented in the present work. The smart system consists of a beam as the host structure and piezoceramic patches as the actuation and sensing elements. An experimental set-up has been developed to obtain the active vibration suppression of smart beam. The set-up consists of a smart cantilever beam, the data acquisition system and a LabView based controller. Experiments are performed for different beam specimen. The coupled effcient layerwise (zigzag theory is used for theoretical finite element modeling. The finite element model is free of shear locking. The beam element has two nodes with four mechanical and a variable number of electric degrees of freedom at each node. In the thickness direction, the electric field is approximated as piecewise linear across an arbitrary number of sub-layers in the piezoelectric layers. Cubic Hermite interpolation is used for the deflection, and linear interpolation is used for the axial displacement and the shear rotation. Undamped Natural Frequencies are obtained by solving the Eigen Value problem using Subspace Iteration method for cantilever beam. A state space model characterizing the dynamics of the physical system is developed from experimental results using PID approach for the purpose of control law design. The experimental results obtained by using the active vibration control system have demonstrated the validity and effciency of PID controller. Experiments are conducted to compare the controlling of various cantilever beams of different sizes. It shows that the present actuator and sensor based control method is effective and the LabView control plots for various beams can be used as a benchmark for analytical work. The results are compared with ABAQUS software and 1D Finite element formulation based on zigzag theory.

  19. SPS beam to the West Hall

    CERN Multimedia

    CERN PhotoLab

    1976-01-01

    One of the two target stations feeding the West Hall (see Annual Report 1976). After the proton beam was split into three branches, the outer two were directed on to targets in the cast iron shielding box, the centre one passing through the box to another target station downstream. Five different targets could be put in each beam, controlled by the mechanism seen on top.

  20. Modelling and Testing of the Piezoelectric Beam as Energy Harvesting System

    Directory of Open Access Journals (Sweden)

    Koszewnik Andrzej

    2016-12-01

    Full Text Available The paper describes modelling and testing of the piezoelectric beam as energy harvesting system. The cantilever beam with two piezo-elements glued onto its surface is considered in the paper. As result of carried out modal analysis of the beam the natural frequencies and modes shapes are determined. The obtained results in the way mentioned above allow to estimate such location of the piezo-actuator on the beam where the piezo generates maximal values of modal control forces. Experimental investigations carried out in the laboratory allow to verify results of natural frequencies obtained during simulation and also testing of the beam in order to obtain voltage from vibration with help of the piezo-harvester. The obtained values of voltage stored on the capacitor C0 shown that the best results are achieved for the beam excited to vibration with third natural frequency, but the worst results for the beam oscillating with the first natural frequency.

  1. Natural Vibration of a Beam with a Breathing Oblique Crack

    Directory of Open Access Journals (Sweden)

    Yijiang Ma

    2017-01-01

    Full Text Available An analytical method is proposed to calculate the natural frequency of a cantilever beam with a breathing oblique crack. A double-linear-springs-model is developed in the modal analysis process to describe the breathing oblique crack, and the breathing behaviour of the oblique crack is objectively simulated. The finite element method (FEM analysis software ABAQUS is used to calculate the geometric correction factors when the cracked plate is subjected to a pure bending moment at different oblique crack angles and relative depths. The Galerkin method is applied to simplify the cracked beam to a single degree of freedom system, allowing the natural frequency of the beam with the breathing oblique crack to be calculated. Compared with the natural frequencies of the breathing oblique cracked beam obtained using the ABAQUS FEM method, the proposed analytical method exhibits a high computational accuracy, with a maximum error of only 4.65%.

  2. Large deflection of viscoelastic beams using fractional derivative model

    International Nuclear Information System (INIS)

    Bahranini, Seyed Masoud Sotoodeh; Eghtesad, Mohammad; Ghavanloo, Esmaeal; Farid, Mehrdad

    2013-01-01

    This paper deals with large deflection of viscoelastic beams using a fractional derivative model. For this purpose, a nonlinear finite element formulation of viscoelastic beams in conjunction with the fractional derivative constitutive equations has been developed. The four-parameter fractional derivative model has been used to describe the constitutive equations. The deflected configuration for a uniform beam with different boundary conditions and loads is presented. The effect of the order of fractional derivative on the large deflection of the cantilever viscoelastic beam, is investigated after 10, 100, and 1000 hours. The main contribution of this paper is finite element implementation for nonlinear analysis of viscoelastic fractional model using the storage of both strain and stress histories. The validity of the present analysis is confirmed by comparing the results with those found in the literature.

  3. SplitDist—Calculating Split-Distances for Sets of Trees

    DEFF Research Database (Denmark)

    Mailund, T

    2004-01-01

    We present a tool for comparing a set of input trees, calculating for each pair of trees the split-distances, i.e., the number of splits in one tree not present in the other.......We present a tool for comparing a set of input trees, calculating for each pair of trees the split-distances, i.e., the number of splits in one tree not present in the other....

  4. Study on Vibration of Heavy-Precision Robot Cantilever Based on Time-varying Glowworm Swarm Optimization Algorithm

    Science.gov (United States)

    Luo, T. H.; Liang, S.; Miao, C. B.

    2017-12-01

    A method of terminal vibration analysis based on Time-varying Glowworm Swarm Optimization algorithm is proposed in order to solve the problem that terminal vibration of the large flexible robot cantilever under heavy load precision.The robot cantilever of the ballastless track is used as the research target and the natural parameters of the flexible cantilever such as the natural frequency, the load impact and the axial deformation is considered. Taking into account the change of the minimum distance between the glowworm individuals, the terminal vibration response and adaptability could meet. According to the Boltzmann selection mechanism, the dynamic parameters in the motion simulation process are determined, while the influence of the natural frequency and the load impact as well as the axial deformation on the terminal vibration is studied. The method is effective and stable, which is of great theoretical basis for the study of vibration control of flexible cantilever terminal.

  5. PZT cantilevers integrated with heaters and new piezoelectric sensors for SPM-based nano-data storage application

    International Nuclear Information System (INIS)

    Lee, Caroline Sunyong; Nam, Hyo Jin; Kim, Young Sik; Jin, Won Hyeog; Bu, Jong Uk

    2004-01-01

    Silicon cantilevers integrated with heaters and piezoelectric sensors were used to demonstrate a thermomechanical writing system and a piezoelectric readback system for a low-power Scanning-Probe-Microscopy data-storage system. To demonstrate a thermal writing system, a thin polymer medium was used to record data bits, 40 nm in diameter and 20 nm in depth, by using this silicon cantilever. A sensitivity of 0.22 fC/nm was obtained by using the fabricated cantilever. Finally, to obtain readback signals using the piezoelectric cantilever, a patterned oxide wafer of 100-nm depth was scanned to show the distinctive charge signals. Therefore, the piezoelectric readback method using a PZT sensor for a low power system was successfully demonstrated in this paper.

  6. Determination of Fluid Density and Viscosity by Analyzing Flexural Wave Propagations on the Vibrating Micro-Cantilever.

    Science.gov (United States)

    Kim, Deokman; Hong, Seongkyeol; Jang, Jaesung; Park, Junhong

    2017-10-27

    The determination of fluid density and viscosity using most cantilever-based sensors is based on changes in resonant frequency and peak width. Here, we present a wave propagation analysis using piezoelectrically excited micro-cantilevers under distributed fluid loading. The standing wave shapes of microscale-thickness cantilevers partially immersed in liquids (water, 25% glycerol, and acetone), and nanoscale-thickness microfabricated cantilevers fully immersed in gases (air at three different pressures, carbon dioxide, and nitrogen) were investigated to identify the effects of fluid-structure interactions to thus determine the fluid properties. This measurement method was validated by comparing with the known fluid properties, which agreed well with the measurements. The relative differences for the liquids were less than 4.8% for the densities and 3.1% for the viscosities, and those for the gases were less than 6.7% for the densities and 7.3% for the viscosities, showing better agreements in liquids than in gases.

  7. Split Questionnaire Design for Massive Surveys

    NARCIS (Netherlands)

    Adiguzel, F.; Wedel, M.

    2008-01-01

    Companies are conducting more and longer surveys than ever before. Massive questionnaires are pervasive in marketing practice. As an alternative to the heuristic methods that are currently used to split questionnaires, this study develops a methodology to design the split questionnaire in a way that

  8. Cheating More when the Spoils Are Split

    Science.gov (United States)

    Wiltermuth, Scott S.

    2011-01-01

    Four experiments demonstrated that people are more likely to cheat when the benefits of doing so are split with another person, even an anonymous stranger, than when the actor alone captures all of the benefits. In three of the studies, splitting the benefits of over-reporting one's performance on a task made such over-reporting seem less…

  9. Standard Model Particles from Split Octonions

    Directory of Open Access Journals (Sweden)

    Gogberashvili M.

    2016-01-01

    Full Text Available We model physical signals using elements of the algebra of split octonions over the field of real numbers. Elementary particles are corresponded to the special elements of the algebra that nullify octonionic norms (zero divisors. It is shown that the standard model particle spectrum naturally follows from the classification of the independent primitive zero divisors of split octonions.

  10. Split Scheduling with Uniform Setup Times

    NARCIS (Netherlands)

    Schalekamp, F.; Sitters, R.A.; van der Ster, S.L.; Stougie, L.; Verdugo, V.; van Zuylen, A.

    2015-01-01

    We study a scheduling problem in which jobs may be split into parts, where the parts of a split job may be processed simultaneously on more than one machine. Each part of a job requires a setup time, however, on the machine where the job part is processed. During setup, a machine cannot process or

  11. Split scheduling with uniform setup times.

    NARCIS (Netherlands)

    F. Schalekamp; R.A. Sitters (René); S.L. van der Ster; L. Stougie (Leen); V. Verdugo; A. van Zuylen

    2015-01-01

    htmlabstractWe study a scheduling problem in which jobs may be split into parts, where the parts of a split job may be processed simultaneously on more than one machine. Each part of a job requires a setup time, however, on the machine where the job part is processed. During setup, a

  12. On split Lie triple systems II

    Indian Academy of Sciences (India)

    Lie triple system with a coherent 0-root space is the direct sum of the family of its minimal ideals, each one being a simple split Lie triple system, and the simplicity of T is characterized. In the present paper we extend these results to arbitrary split Lie triple systems with no restrictions on their 0-root spaces. Keywords.

  13. Analysis the effect of different geometries of AFM's cantilever on the dynamic behavior and the critical forces of three-dimensional manipulation

    International Nuclear Information System (INIS)

    Korayem, Moharam Habibnejad; Saraie, Maniya B.; Saraee, Mahdieh B.

    2017-01-01

    An important challenge when using an atomic force microscope (AFM) is to be able to control the force exerted by the AFM for performing various tasks. Nevertheless, the exerted force is proportional to the deflection of the AFM cantilever, which itself is affected by a cantilever's stiffness coefficient. Many papers have been published so far on the methods of obtaining the stiffness coefficients of AFM cantilevers in 2D; however, a comprehensive model is yet to be presented on 3D cantilever motion. The discrepancies between the equations of the 2D and 3D analysis are due to the number and direction of forces and moments that are applied to a cantilever. Moreover, in the 3D analysis, contrary to the 2D analysis, due to the interaction between the forces and moments applied on a cantilever, its stiffness values cannot be separately expressed for each direction; and instead, a stiffness matrix should be used to correctly derive the relevant equations. In this paper, 3D stiffness coefficient matrices have been obtained for three common cantilever geometries including the rectangular, V-shape and dagger-shape cantilevers. The obtained equations are validated by two methods. In the first approach, the Finite Element Method is combined with the cantilever deflection values computed by using the obtained stiffness matrices. In the second approach, by reducing the problem's parameters, the forces applied on a cantilever along different directions are compared with each other in 2D and 3D cases. Then the 3D manipulation of a stiff nanoparticle is modeled and simulated by using the stiffness matrices obtained for the three cantilever geometries. The obtained results indicate that during the manipulation process, the dagger-shaped and rectangular cantilevers exert the maximum and minimum amounts of forces on the stiff nanoparticle, respectively. Also, by examining the effects of different probe tip geometries, it is realized that a probe tip of cylindrical geometry

  14. Analysis the effect of different geometries of AFM's cantilever on the dynamic behavior and the critical forces of three-dimensional manipulation

    Energy Technology Data Exchange (ETDEWEB)

    Korayem, Moharam Habibnejad, E-mail: hkorayem@iust.ac.ir; Saraie, Maniya B.; Saraee, Mahdieh B.

    2017-04-15

    An important challenge when using an atomic force microscope (AFM) is to be able to control the force exerted by the AFM for performing various tasks. Nevertheless, the exerted force is proportional to the deflection of the AFM cantilever, which itself is affected by a cantilever's stiffness coefficient. Many papers have been published so far on the methods of obtaining the stiffness coefficients of AFM cantilevers in 2D; however, a comprehensive model is yet to be presented on 3D cantilever motion. The discrepancies between the equations of the 2D and 3D analysis are due to the number and direction of forces and moments that are applied to a cantilever. Moreover, in the 3D analysis, contrary to the 2D analysis, due to the interaction between the forces and moments applied on a cantilever, its stiffness values cannot be separately expressed for each direction; and instead, a stiffness matrix should be used to correctly derive the relevant equations. In this paper, 3D stiffness coefficient matrices have been obtained for three common cantilever geometries including the rectangular, V-shape and dagger-shape cantilevers. The obtained equations are validated by two methods. In the first approach, the Finite Element Method is combined with the cantilever deflection values computed by using the obtained stiffness matrices. In the second approach, by reducing the problem's parameters, the forces applied on a cantilever along different directions are compared with each other in 2D and 3D cases. Then the 3D manipulation of a stiff nanoparticle is modeled and simulated by using the stiffness matrices obtained for the three cantilever geometries. The obtained results indicate that during the manipulation process, the dagger-shaped and rectangular cantilevers exert the maximum and minimum amounts of forces on the stiff nanoparticle, respectively. Also, by examining the effects of different probe tip geometries, it is realized that a probe tip of cylindrical geometry

  15. Beam cooling

    OpenAIRE

    Danared, H

    2006-01-01

    Beam cooling is the technique of reducing the momentum spread and increasing the phase-space density of stored particle beams. This paper gives an introduction to beam cooling and Liouville’s theorem, and then it describes the three methods of active beam cooling that have been proven to work so far, namely electron cooling, stochastic cooling, and laser cooling. Ionization cooling is also mentioned briefly.

  16. Molecular beams

    International Nuclear Information System (INIS)

    Pendelbury, J.M.; Smith, K.F.

    1987-01-01

    Studies with directed collision-free beams of particles continue to play an important role in the development of modern physics and chemistry. The deflections suffered by such beams as they pass through electric and magnetic fields or laser radiation provide some of the most direct information about the individual constituents of the beam; the scattering observed when two beams intersect yields important data about the intermolecular forces responsible for the scattering. (author)

  17. Particulate photocatalysts for overall water splitting

    Science.gov (United States)

    Chen, Shanshan; Takata, Tsuyoshi; Domen, Kazunari

    2017-10-01

    The conversion of solar energy to chemical energy is a promising way of generating renewable energy. Hydrogen production by means of water splitting over semiconductor photocatalysts is a simple, cost-effective approach to large-scale solar hydrogen synthesis. Since the discovery of the Honda-Fujishima effect, considerable progress has been made in this field, and numerous photocatalytic materials and water-splitting systems have been developed. In this Review, we summarize existing water-splitting systems based on particulate photocatalysts, focusing on the main components: light-harvesting semiconductors and co-catalysts. The essential design principles of the materials employed for overall water-splitting systems based on one-step and two-step photoexcitation are also discussed, concentrating on three elementary processes: photoabsorption, charge transfer and surface catalytic reactions. Finally, we outline challenges and potential advances associated with solar water splitting by particulate photocatalysts for future commercial applications.

  18. Measurement of Local Si-Nanowire Growth Kinetics Using In situ Transmission Electron Microscopy of Heated Cantilevers

    DEFF Research Database (Denmark)

    Kallesøe, Christian; Wen, Cheng-Yen; Mølhave, Kristian

    2010-01-01

    A technique to study nanowire growth processes on locally heated microcantilevers in situ in a transmission electron microscope has been developed. The in situ observations allow the characterization of the nucleation process of silicon wires, as well as the measurement of growth rates of individ...... to calibrate the cantilever-heater parameters used in finite-element models of cantilever heating profiles, useful for optimization of the design of devices requiring local growth....

  19. A beam intensity profile monitor based on secondary electron emission

    International Nuclear Information System (INIS)

    Berdoz, A.R.; Birchall, J.; Campbell, J.R.; Davis, C.A.; Davison, N.E.; Mosscrop, D.R.; Page, S.A.; Ramsay, W.D.; Sekulovich, A.M.; Van Oers, W.T.H.; MIschke, R.E.

    1991-03-01

    Two dual function intensity profile monitors have been designed for a measurement of parity violation in antiproton-proton scattering at about 230 MeV using longitudinally polarized protons. Each device contains a set of split secondary electron emission (SEM) foils to determine the median of the beam current distribution (in x and y). The split foils, coupled through servoamplifiers and operational amplifiers to upstream air core steering magnets, have demonstrated the ability to hold the beam position stable to within ± 3 μm after one hour of data taking with a 100 nA, 15 mm FWHM Gaussian beam. (Author) 16 refs., 10 figs., tab

  20. Cantilever measurements of surface stress, surface reconstruction, film stress and magnetoelastic stress of monolayersc

    Directory of Open Access Journals (Sweden)

    Jürgen Kirschner

    2008-07-01

    Full Text Available We review the application of cantilever-based stress measurements in surface science and magnetism. The application of thin (thickness appr. 0.1 mm single crystalline substrates as cantilevers has been used successfully to measure adsorbate-induced surface stress changes, lattice misfit induced film stress, and magneto-elastic stress of ferromagnetic monolayers. Surface stress changes as small as 0.01 N/m can be readily measured, and this translates into a sensitivity for adsorbate-coverage well below 0.01 of one layer. Stress as large as several GPa, beyond the elasticity limits of high strength materials, is measured, and it is ascribed to the lattice misfit between film and substrate. Our results point at the intimate relation between surface stress and surface reconstruction, stress-induced structural changes in epitaxially strained films, and strain-induced modifications of the magneto-elastic coupling in ferromagnetic monolayers.

  1. Cantilever measurements of surface stress, surface reconstruction, film stress and magnetoelastic stress of monolayers.

    Science.gov (United States)

    Sander, Dirk; Tian, Zhen; Kirschner, Jürgen

    2008-07-29

    We review the application of cantilever-based stress measurements in surface science and magnetism. The application of thin (thickness appr. 0.1 mm) single crystalline substrates as cantilevers has been used successfully to measure adsorbate-induced surface stress changes, lattice misfit induced film stress, and magneto-elastic stress of ferromagnetic monolayers. Surface stress changes as small as 0.01 N/m can be readily measured, and this translates into a sensitivity for adsorbate-coverage well below 0.01 of one layer. Stress as large as several GPa, beyond the elasticity limits of high strength materials, is measured, and it is ascribed to the lattice misfit between film and substrate. Our results point at the intimate relation between surface stress and surface reconstruction, stress-induced structural changes in epitaxially strained films, and strain-induced modifications of the magneto-elastic coupling in ferromagnetic monolayers.

  2. Clustering mechanism of ethanol-water mixtures investigated with photothermal microfluidic cantilever deflection spectroscopy

    Science.gov (United States)

    Ghoraishi, M. S.; Hawk, J. E.; Phani, Arindam; Khan, M. F.; Thundat, T.

    2016-04-01

    The infrared-active (IR) vibrational mode of ethanol (EtOH) associated with the asymmetrical stretching of the C-C-O bond in pico-liter volumes of EtOH-water binary mixtures is calorimetrically measured using photothermal microfluidic cantilever deflection spectroscopy (PMCDS). IR absorption by the confined liquid results in wavelength dependent cantilever deflections, thus providing a complementary response to IR absorption revealing a complex dipole moment dependence on mixture concentration. Solvent-induced blue shifts of the C-C-O asymmetric vibrational stretch for both anti and gauche conformers of EtOH were precisely monitored for EtOH concentrations ranging from 20-100% w/w. Variations in IR absorption peak maxima show an inverse dependence on induced EtOH dipole moment (μ) and is attributed to the complex clustering mechanism of EtOH-water mixtures.

  3. A virtual instrument to standardise the calibration of atomic force microscope cantilevers.

    Science.gov (United States)

    Sader, John E; Borgani, Riccardo; Gibson, Christopher T; Haviland, David B; Higgins, Michael J; Kilpatrick, Jason I; Lu, Jianing; Mulvaney, Paul; Shearer, Cameron J; Slattery, Ashley D; Thorén, Per-Anders; Tran, Jim; Zhang, Heyou; Zhang, Hongrui; Zheng, Tian

    2016-09-01

    Atomic force microscope (AFM) users often calibrate the spring constants of cantilevers using functionality built into individual instruments. This calibration is performed without reference to a global standard, hindering the robust comparison of force measurements reported by different laboratories. Here, we describe a virtual instrument (an internet-based initiative) whereby users from all laboratories can instantly and quantitatively compare their calibration measurements to those of others-standardising AFM force measurements-and simultaneously enabling non-invasive calibration of AFM cantilevers of any geometry. This global calibration initiative requires no additional instrumentation or data processing on the part of the user. It utilises a single website where users upload currently available data. A proof-of-principle demonstration of this initiative is presented using measured data from five independent laboratories across three countries, which also allows for an assessment of current calibration.

  4. Optimum design of reinforced concrete cantilever retaining walls with particle swarm optimization

    Directory of Open Access Journals (Sweden)

    Ali Haydar KAYHAN

    2016-06-01

    Full Text Available In this study, a Particle Swarm Optimization (PSO based algorithm is used for optimum design of reinforced concrete cantilever retaining walls. Besides vertical loads, both active and static lateral ground pressures are considered for design. Reinforced concrete design rules defined in TS-500 and checking procedures about sliding, overturning and bearing capacity failures defined in TS-7994 are taken into account as constraints of the optimization problem. In order to evaluate the relationship between optimum design results and values of PSO solution parameters, a sensitivity analysis is performed. Results show that, PSO based solution algorithm may be used as an efficient tool for optimum design of reinforced concrete cantilever retaining walls by satisfying all considered constraints.

  5. Cantilever-based sensing: the origin of surface stress and optimization strategies

    International Nuclear Information System (INIS)

    Godin, Michel; Tabard-Cossa, Vincent; Miyahara, Yoichi; Grutter, Peter; Monga, Tanya; Bruce Lennox, R; Williams, P J; Beaulieu, L Y

    2010-01-01

    Many interactions drive the adsorption of molecules on surfaces, all of which can result in a measurable change in surface stress. This article compares the contributions of various possible interactions to the overall induced surface stress for cantilever-based sensing applications. The surface stress resulting from adsorption-induced changes in the electronic density of the underlying surface is up to 2-4 orders of magnitude larger than that resulting from intermolecular electrostatic or Lennard-Jones interactions. We reveal that the surface stress associated with the formation of high quality alkanethiol self-assembled monolayers on gold surfaces is independent of the molecular chain length, supporting our theoretical findings. This provides a foundation for the development of new strategies for increasing the sensitivity of cantilever-based sensors for various applications.

  6. Enhancement of Frequency Stability Using Synchronization of a Cantilever Array for MEMS-Based Sensors

    Directory of Open Access Journals (Sweden)

    Francesc Torres

    2016-10-01

    Full Text Available Micro and nano electromechanical resonators have been widely used as single or multiple-mass detection sensors. Smaller devices with higher resonance frequencies and lower masses offer higher mass responsivities but suffer from lower frequency stability. Synchronization phenomena in multiple MEMS resonators have become an important issue because they allow frequency stability improvement, thereby preserving mass responsivity. The authors present an array of five cantilevers (CMOS-MEMS system that are forced to vibrate synchronously to enhance their frequency stability. The frequency stability has been determined in closed-loop configuration for long periods of time by calculating the Allan deviation. An Allan deviation of 0.013 ppm (@ 1 s averaging time for a 1 MHz cantilever array MEMS system was obtained at the synchronized mode, which represents a 23-fold improvement in comparison with the non-synchronized operation mode (0.3 ppm.

  7. High-speed force mapping on living cells with a small cantilever atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Braunsmann, Christoph; Seifert, Jan; Rheinlaender, Johannes; Schäffer, Tilman E., E-mail: Tilman.Schaeffer@uni-tuebingen [Institute of Applied Physics and LISA, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen (Germany)

    2014-07-15

    The imaging speed of the wide-spread force mapping mode for quantitative mechanical measurements on soft samples in liquid with the atomic force microscope (AFM) is limited by the bandwidth of the z-scanner and viscous drag forces on the cantilever. Here, we applied high-speed, large scan-range atomic force microscopy and small cantilevers to increase the speed of force mapping by ≈10−100 times. This allowed resolving dynamic processes on living mouse embryonic fibroblasts. Cytoskeleton reorganization during cell locomotion, growth of individual cytoskeleton fibers, cell blebbing, and the formation of endocytic pits in the cell membrane were observed. Increasing the force curve rate from 2 to 300 Hz increased the measured apparent Young's modulus of the cells by about 10 times, which facilitated force mapping measurements at high speed.

  8. High-speed force mapping on living cells with a small cantilever atomic force microscope

    International Nuclear Information System (INIS)

    Braunsmann, Christoph; Seifert, Jan; Rheinlaender, Johannes; Schäffer, Tilman E.

    2014-01-01

    The imaging speed of the wide-spread force mapping mode for quantitative mechanical measurements on soft samples in liquid with the atomic force microscope (AFM) is limited by the bandwidth of the z-scanner and viscous drag forces on the cantilever. Here, we applied high-speed, large scan-range atomic force microscopy and small cantilevers to increase the speed of force mapping by ≈10−100 times. This allowed resolving dynamic processes on living mouse embryonic fibroblasts. Cytoskeleton reorganization during cell locomotion, growth of individual cytoskeleton fibers, cell blebbing, and the formation of endocytic pits in the cell membrane were observed. Increasing the force curve rate from 2 to 300 Hz increased the measured apparent Young's modulus of the cells by about 10 times, which facilitated force mapping measurements at high speed

  9. Calibration of higher eigenmode spring constants of atomic force microscope cantilevers

    Energy Technology Data Exchange (ETDEWEB)

    Lozano, Jose R; Garcia, Ricardo [IMM-Instituto de Microelectronica de Madrid (CNM-CSIC), Isaac Newton 8, PTM, E-28760 Tres Cantos, Madrid (Spain); Kiracofe, Daniel; Melcher, John; Raman, Arvind, E-mail: raman@purdue.edu [Birck Nanotechnology Center and School of Mechanical Engineering, Purdue University, West Lafayette, IN 47904-2088 (United States)

    2010-11-19

    Standard spring constant calibration methods are compared when applied to higher eigenmodes of cantilevers used in dynamic atomic force microscopy (dAFM). Analysis shows that Sader's original method (Sader et al 1999 Rev. Sci. Instrum. 70 3967-9), which relies on a priori knowledge of the eigenmode shape, is poorly suited for the calibration of higher eigenmodes. On the other hand, the thermal noise method (Hutter and Bechhoefer 1993 Rev. Sci. Instrum. 64 1868-73) does not require knowledge of the eigenmode and remains valid for higher eigenmodes of the dAFM probe. Experimental measurements of thermal vibrations in air for three representative cantilevers are provided to support the theoretical results.

  10. A 100 nanometer scale resistive heater-thermometer on a silicon cantilever.

    Science.gov (United States)

    Dai, Z; King, W P; Park, K

    2009-03-04

    This paper reports a method for fabricating a 100 nm scale heater-thermometer into a silicon microcantilever based on contact photolithography and a controlled annealing process. The heater is formed during a photolithography process that can achieve a minimum feature size of about 1 microm, while careful control of doping and annealing parameters allows the heater size to be further decreased, to a width of 100 nm. The heater is fabricated onto the free end of a silicon cantilever suitable for scanning probe microscopy, and can be integrated into cantilevers with or without sharp tips. The fabricated heater has a maximum temperature of over 700 degrees C, and a heating time of 56 micros to reach 500 degrees C.

  11. Computational model for noncontact atomic force microscopy: energy dissipation of cantilever.

    Science.gov (United States)

    Senda, Yasuhiro; Blomqvist, Janne; Nieminen, Risto M

    2016-09-21

    We propose a computational model for noncontact atomic force microscopy (AFM) in which the atomic force between the cantilever tip and the surface is calculated using a molecular dynamics method, and the macroscopic motion of the cantilever is modeled by an oscillating spring. The movement of atoms in the tip and surface is connected with the oscillating spring using a recently developed coupling method. In this computational model, the oscillation energy is dissipated, as observed in AFM experiments. We attribute this dissipation to the hysteresis and nonconservative properties of the interatomic force that acts between the atoms in the tip and sample surface. The dissipation rate strongly depends on the parameters used in the computational model.

  12. Design and fabrication of a micro PZT cantilever array actuator for applications in fluidic systems

    DEFF Research Database (Denmark)

    Kim, H.; In, C.; Yoon, Gil Ho

    2005-01-01

    In this article, a micro cantilever array actuated by PZT films is designed and fabricated for micro fluidic systems. The design features for maximizing tip deflections and minimizing fluid leakage are described. The governing equation of the composite PZT cantilever is derived and the actuating...... behavior predicted. The calculated value of the tip deflection was 15 pm at 5 V. The fabrication process from SIMOX (Separation by oxygen ion implantation) wafer is presented in detail with the PZT film deposition process. The PZT films are characterized by investigating the ferroelectric properties......, dielectric constant, and dielectric loss. Tip deflections of 12 mu m at 5 V are measured, which agreed well with the predicted value. The 18 mu l/s leakage rate of air was observed at a pressure difference of 1000 Pa. Micro cooler is introduced, and its possible application to micro compressor is discussed....

  13. Harvested power and sensitivity analysis of vibrating shoe-mounted piezoelectric cantilevers

    International Nuclear Information System (INIS)

    Moro, L; Benasciutti, D

    2010-01-01

    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. Effect of cantilever geometry on the optical lever sensitivities and thermal noise method of the atomic force microscope.

    Science.gov (United States)

    Sader, John E; Lu, Jianing; Mulvaney, Paul

    2014-11-01

    Calibration of the optical lever sensitivities of atomic force microscope (AFM) cantilevers is especially important for determining the force in AFM measurements. These sensitivities depend critically on the cantilever mode used and are known to differ for static and dynamic measurements. Here, we calculate the ratio of the dynamic and static sensitivities for several common AFM cantilevers, whose shapes vary considerably, and experimentally verify these results. The dynamic-to-static optical lever sensitivity ratio is found to range from 1.09 to 1.41 for the cantilevers studied - in stark contrast to the constant value of 1.09 used widely in current calibration studies. This analysis shows that accuracy of the thermal noise method for the static spring constant is strongly dependent on cantilever geometry - neglect of these dynamic-to-static factors can induce errors exceeding 100%. We also discuss a simple experimental approach to non-invasively and simultaneously determine the dynamic and static spring constants and optical lever sensitivities of cantilevers of arbitrary shape, which is applicable to all AFM platforms that have the thermal noise method for spring constant calibration.

  15. Study of Alzheimer's Disease-Related Biophysical Kinetics with a Microslit-Embedded Cantilever Sensor in a Liquid Environment.

    Science.gov (United States)

    Chae, Myung-Sic; Kim, Jinsik; Yoo, Yong Kyoung; Lee, Jeong Hoon; Kim, Tae Geun; Hwang, Kyo Seon

    2017-08-07

    A microsized slit-embedded cantilever sensor (slit cantilever) was fabricated and evaluated as a biosensing platform in a liquid environment. In order to minimize the degradation caused by viscous damping, a 300 × 100 µm² (length × width) sized cantilever was released by a 5 µm gap-surrounding and vibrated by an internal piezoelectric-driven self-actuator. Owing to the structure, when the single side of the slit cantilever was exposed to liquid a significant quality factor (Q = 35) could be achieved. To assess the sensing performance, the slit cantilever was exploited to study the biophysical kinetics related to Aβ peptide. First, the quantification of Aβ peptide with a concentration of 10 pg/mL to 1 μg/mL was performed. The resonant responses exhibited a dynamic range from 100 pg/mL to 100 ng/mL (-56.5 to -774 ΔHz) and a dissociation constant (K D ) of binding affinity was calculated as 1.75 nM. Finally, the Aβ self-aggregation associated with AD pathogenesis was monitored by adding monomeric Aβ peptides. As the concentration of added analyte increased from 100 ng/mL to 10 µg/mL, both the frequency shift values (-813 to -1804 ΔHz) and associate time constant increased. These results showed the excellent sensing performance of the slit cantilever overcoming a major drawback in liquid environments to become a promising diagnostic tool candidate.

  16. A pressure gauge based on gas density measurement from analysis of the thermal noise of an atomic force microscope cantilever.

    Science.gov (United States)

    Seo, Dongjin; Paul, Mark R; Ducker, William A

    2012-05-01

    We describe a gas-density gauge based on the analysis of the thermally-driven fluctuations of an atomic force microscope (AFM) cantilever. The fluctuations are modeled as a ring-down of a simple harmonic oscillator, which allows fitting of the resonance frequency and damping of the cantilever, which in turn yields the gas density. The pressure is obtained from the density using the known equation of state. In the range 10-220 kPa, the pressure readings from the cantilever gauge deviate by an average of only about 5% from pressure readings on a commercial gauge. The theoretical description we use to determine the pressure from the cantilever motion is based upon the continuum hypothesis, which sets a minimum pressure for our analysis. It is anticipated that the cantilever gauge could be extended to measure lower pressures given a molecular theoretical description. Alternatively, the gauge could be calibrated for use in the non-continuum range. Our measurement technique is similar to previous AFM cantilever measurements, but the analysis produces improved accuracy.

  17. Segmentation of a Vibro-Shock Cantilever-Type Piezoelectric Energy Harvester Operating in Higher Transverse Vibration Modes

    Directory of Open Access Journals (Sweden)

    Darius Zizys

    2015-12-01

    Full Text Available The piezoelectric transduction mechanism is a common vibration-to-electric energy harvesting approach. Piezoelectric energy harvesters are typically mounted on a vibrating host structure, whereby alternating voltage output is generated by a dynamic strain field. A design target in this case is to match the natural frequency of the harvester to the ambient excitation frequency for the device to operate in resonance mode, thus significantly increasing vibration amplitudes and, as a result, energy output. Other fundamental vibration modes have strain nodes, where the dynamic strain field changes sign in the direction of the cantilever length. The paper reports on a dimensionless numerical transient analysis of a cantilever of a constant cross-section and an optimally-shaped cantilever with the objective to accurately predict the position of a strain node. Total effective strain produced by both cantilevers segmented at the strain node is calculated via transient analysis and compared to the strain output produced by the cantilevers segmented at strain nodes obtained from modal analysis, demonstrating a 7% increase in energy output. Theoretical results were experimentally verified by using open-circuit voltage values measured for the cantilevers segmented at optimal and suboptimal segmentation lines.

  18. Parametric resonance in concrete beam-columns

    Directory of Open Access Journals (Sweden)

    Mamta R. Sharma

    Full Text Available A dynamic instability, called parametric resonance, is exhibited by undampedelastic beam-columns when under the action of pulsating axial force. The scope of the existing theory of parametric resonance is restricted to physically linear beam-columns undergoing finite lateral displacements. In this Paper, the dynamic behaviour of physically nonlinear elastic cracked concrete beam-columns under pulsating axial force and constant lateral force is investigated. The constitutive equations derived earlier by Authors in the form of force-displacement relations are employed here to formulate equations of motion of the SDOF cantilever with mass lumped at its free end. The expected phenomenon of parametric resonance is exhibited in the form of regular subharmonic resonance at about the frequency ratio of two. Resonance peaks broaden with increase in pulsating force. Like damping, physical nonlinearity is also predicted to stabilize the dynamic response at resonance frequencies. In some particular statically unstable conditions, the loss of dynamic stability is shown to occur by divergence. Unexpectedly, similar phenomenon of parametric resonance is exhibited by these physically nonlinear beam-columns undergoing even small lateral displacements. The contribution made to the theory of parametric resonance and the potential relevance of the proposed theory to design of concrete beam-columns is discussed.

  19. Low-power Power Management Circuit Design for Small Scale Energy Harvesting Using Piezoelectric Cantilevers

    OpenAIRE

    Kong, Na

    2011-01-01

    The batteries used to power wireless sensor nodes have become a major roadblock for the wide deployment. Harvesting energy from mechanical vibrations using piezoelectric cantilevers provides possible means to recharge the batteries or eliminate them. Raw power harvested from ambient sources should be conditioned and regulated to a desired voltage level before its application to electronic devices. The efficiency and self-powered operation of a power conditioning and management circuit is a ke...

  20. Nonlinear behaviour of cantilevered carbon nanotube resonators based on a new nonlinear electrostatic load model

    Science.gov (United States)

    Farokhi, Hamed; Païdoussis, Michael P.; Misra, Arun K.

    2018-04-01

    The present study examines the nonlinear behaviour of a cantilevered carbon nanotube (CNT) resonator and its mass detection sensitivity, employing a new nonlinear electrostatic load model. More specifically, a 3D finite element model is developed in order to obtain the electrostatic load distribution on cantilevered CNT resonators. A new nonlinear electrostatic load model is then proposed accounting for the end effects due to finite length. Additionally, a new nonlinear size-dependent continuum model is developed for the cantilevered CNT resonator, employing the modified couple stress theory (to account for size-effects) together with the Kelvin-Voigt model (to account for nonlinear damping); the size-dependent model takes into account all sources of nonlinearity, i.e. geometrical and inertial nonlinearities as well as nonlinearities associated with damping, small-scale, and electrostatic load. The nonlinear equation of motion of the cantilevered CNT resonator is obtained based on the new models developed for the CNT resonator and the electrostatic load. The Galerkin method is then applied to the nonlinear equation of motion, resulting in a set of nonlinear ordinary differential equations, consisting of geometrical, inertial, electrical, damping, and size-dependent nonlinear terms. This high-dimensional nonlinear discretized model is solved numerically utilizing the pseudo-arclength continuation technique. The nonlinear static and dynamic responses of the system are examined for various cases, investigating the effect of DC and AC voltages, length-scale parameter, nonlinear damping, and electrostatic load. Moreover, the mass detection sensitivity of the system is examined for possible application of the CNT resonator as a nanosensor.

  1. Actuating mechanism and design of a cylindrical traveling wave ultrasonic motor using cantilever type composite transducer.

    Directory of Open Access Journals (Sweden)

    Yingxiang Liu

    Full Text Available BACKGROUND: Ultrasonic motors (USM are based on the concept of driving the rotor by a mechanical vibration excited on the stator via piezoelectric effect. USM exhibit merits such as simple structure, quick response, quiet operation, self-locking when power off, nonelectromagnetic radiation and higher position accuracy. PRINCIPAL FINDINGS: A cylindrical type traveling wave ultrasonic motor using cantilever type composite transducer was proposed in this paper. There are two cantilevers on the outside surface of cylinder, four longitudinal PZT ceramics are set between the cantilevers, and four bending PZT ceramics are set on each outside surface of cantilevers. Two degenerate flexural vibration modes spatially and temporally orthogonal to each other in the cylinder are excited by the composite transducer. In this new design, a single transducer can excite a flexural traveling wave in the cylinder. Thus, elliptical motions are achieved on the teeth. The actuating mechanism of proposed motor was analyzed. The stator was designed with FEM. The two vibration modes of stator were degenerated. Transient analysis was developed to gain the vibration characteristic of stator, and results indicate the motion trajectories of nodes on the teeth are nearly ellipses. CONCLUSIONS: The study results verify the feasibility of the proposed design. The wave excited in the cylinder isn't an ideal traveling wave, and the vibration amplitudes are inconsistent. The distortion of traveling wave is generated by the deformation of bending vibration mode of cylinder, which is caused by the coupling effect between the cylinder and transducer. Analysis results also prove that the objective motions of nodes on the teeth are three-dimensional vibrations. But, the vibration in axial direction is minute compared with the vibrations in circumferential and radial direction. The results of this paper can guide the development of this new type of motor.

  2. Differential correction system of laser beam directional dithering based on symmetrical beamsplitter

    Science.gov (United States)

    Hongwei, Yang; Wei, Tao; Xiaoqia, Yin; Hui, Zhao

    2018-02-01

    This paper proposes a differential correction system with a differential optical path and a symmetrical beamsplitter for correcting the directional dithering of the laser beams. This system can split a collimated laser beam into two laser beams with equal and opposite movements. Thus, the positional averages of the two split laser beams remain constant irrespective of the dithering angle. The symmetrical beamsplitter designed based on transfer matrix principle is to balance the optical paths and irradiances of the two laser beams. Experimental results show that the directional dithering is reduced to less than one-pixel value. Finally, two examples show that this system can be widely used in one-dimensional measurement.

  3. A pencil beam algorithm for helium ion beam therapy.

    Science.gov (United States)

    Fuchs, Hermann; Strobele, Julia; Schreiner, Thomas; Hirtl, Albert; Georg, Dietmar

    2012-11-01

    To develop a flexible pencil beam algorithm for helium ion beam therapy. Dose distributions were calculated using the newly developed pencil beam algorithm and validated using Monte Carlo (MC) methods. The algorithm was based on the established theory of fluence weighted elemental pencil beam (PB) kernels. Using a new real-time splitting approach, a minimization routine selects the optimal shape for each sub-beam. Dose depositions along the beam path were determined using a look-up table (LUT). Data for LUT generation were derived from MC simulations in water using GATE 6.1. For materials other than water, dose depositions were calculated by the algorithm using water-equivalent depth scaling. Lateral beam spreading caused by multiple scattering has been accounted for by implementing a non-local scattering formula developed by Gottschalk. A new nuclear correction was modelled using a Voigt function and implemented by a LUT approach. Validation simulations have been performed using a phantom filled with homogeneous materials or heterogeneous slabs of up to 3 cm. The beams were incident perpendicular to the phantoms surface with initial particle energies ranging from 50 to 250 MeV/A with a total number of 10(7) ions per beam. For comparison a special evaluation software was developed calculating the gamma indices for dose distributions. In homogeneous phantoms, maximum range deviations between PB and MC of less than 1.1% and differences in the width of the distal energy fall off of the Bragg-Peak from 80% to 20% of less than 0.1 mm were found. Heterogeneous phantoms using layered slabs satisfied a γ-index criterion of 2%/2mm of the local value except for some single voxels. For more complex phantoms using laterally arranged bone-air slabs, the γ-index criterion was exceeded in some areas giving a maximum γ-index of 1.75 and 4.9% of the voxels showed γ-index values larger than one. The calculation precision of the presented algorithm was considered to be sufficient

  4. Vibration of nonuniform carbon nanotube with attached mass via nonlocal Timoshenko beam theory

    International Nuclear Information System (INIS)

    Tang, Hai Li; Shen, Zhi Bin; Li, Dao Kui

    2014-01-01

    This paper studies the vibrational behavior of nonuniform single-walled carbon nanotube (SWCNT) carrying a nanoparticle. A nonuniform cantilever beam with a concentrated mass at the free end is analyzed according to the nonlocal Timoshenko beam theory. A governing equation of a nonuniform SWCNT with attached mass is established. The transfer function method incorporating with the perturbation method is utilized to obtain the resonant frequencies of a vibrating nonlocal cantilever-mass system. The effects of the nonlocal parameter, taper ratio and attached mass on the natural frequencies and frequency shifts are discussed. Obtained results indicate that the sensitivity of the frequency shifts on the attached mass increases when the length-to-diameter ratio decreases. Tapered SWCNT possesses higher fundamental frequencies if the taper ratio becomes larger.

  5. Polymeric Flexible Immunosensor Based on Piezoresistive Micro-Cantilever with PEDOT/PSS Conductive Layer

    Directory of Open Access Journals (Sweden)

    Rui Zhao

    2018-02-01

    Full Text Available In this paper, a fully polymeric micro-cantilever with the surface passivation layer of parylene-C and the strain resistor of poly(3,4-ethylenedioxythiophene/poly (styrene sulfonate (PEDOT/PSS was proposed and demonstrated for immunoassays. By optimizing the design and fabrication of the polymeric micro-cantilever, a square resistance of 220 Ω/□ for PEDOT/PSS conductive layer have been obtained. The experimental spring constant and the deflection sensitivity were measured to be 0.017 N/m and 8.59 × 10−7 nm−1, respectively. The biological sensing performances of polymeric micro-cantilever were investigated by the immunoassay for human immunoglobulin G (IgG. The immunosensor was experimentally demonstrated to have a linear behavior for the detection of IgG within the concentrations of 10~100 ng/mL with a limit of detection (LOD of 10 ng/mL. The experimental results indicate that the proposed polymeric flexible conductive layer-based sensors are capable of detecting trace biological substances.

  6. Label-free glucose detection using cantilever sensor technology based on gravimetric detection principles.

    Science.gov (United States)

    Hsieh, Shuchen; Hsieh, Shu-Ling; Hsieh, Chiung-Wen; Lin, Po-Chiao; Wu, Chun-Hsin

    2013-01-01

    Efficient maintenance of glucose homeostasis is a major challenge in diabetes therapy, where accurate and reliable glucose level detection is required. Though several methods are currently used, these suffer from impaired response and often unpredictable drift, making them unsuitable for long-term therapeutic practice. In this study, we demonstrate a method that uses a functionalized atomic force microscope (AFM) cantilever as the sensor for reliable glucose detection with sufficient sensitivity and selectivity for clinical use. We first modified the AFM tip with aminopropylsilatrane (APS) and then adsorbed glucose-specific lectin concanavalin A (Con A) onto the surface. The Con A/APS-modified probes were then used to detect glucose by monitoring shifts in the cantilever resonance frequency. To confirm the molecule-specific interaction, AFM topographical images were acquired of identically treated silicon substrates which indicated a specific attachment for glucose-Con A and not for galactose-Con A. These results demonstrate that by monitoring the frequency shift of the AFM cantilever, this sensing system can detect the interaction between Con A and glucose, one of the biomolecule recognition processes, and may assist in the detection and mass quantification of glucose for clinical applications with very high sensitivity.

  7. Enhancing output power of a piezoelectric cantilever energy harvester using an oscillator

    International Nuclear Information System (INIS)

    Liu, Haili; Huang, Zhenyu; Xu, Tianzhu; Chen, Dayue

    2012-01-01

    The piezoelectric cantilever with a tip mass (Mass-PC), as a conventional vibration energy harvester, usually works at its fundamental frequency matching ambient excitation. By attaching an oscillator to a piezoelectric cantilever (Osc-PC), a double-mode energy harvester is developed to harvest more power from two matched ambient driving frequencies. Meanwhile, it allows the first operating frequency of the Osc-PC to be adjusted to be very low with only a limited mass attached. A distributed-parameter model of this harvester and the explicit expressions of its operating frequencies are derived to analyze and design the Osc-PC. Numerical investigations reveal that a heaver oscillator placed near the clamped end of the piezoelectric cantilever has better performance at the given exciting frequencies. Following the specified design criteria, an Osc-PC whose operating frequencies match two given exciting frequencies was constructed for the purpose of experimental testing. The results show that, compared to that of a corresponding Mass-PC whose operating frequency matches the lower exciting frequency, the energy harvesting efficiency of the Osc-PC increases by almost four times at the first operating frequency, while the output power at the second operating frequency of the Osc-PC accounts for 68% of that of the Mass-PC. (paper)

  8. Coupled molecular and cantilever dynamics model for frequency-modulated atomic force microscopy.

    Science.gov (United States)

    Klocke, Michael; Wolf, Dietrich E

    2016-01-01

    A molecular dynamics model is presented, which adds harmonic potentials to the atomic interactions to mimic the elastic properties of an AFM cantilever. It gives new insight into the correlation between the experimentally monitored frequency shift and cantilever damping due to the interaction between tip atoms and scanned surface. Applying the model to ionic crystals with rock salt structure two damping mechanisms are investigated, which occur separately or simultaneously depending on the tip position. These mechanisms are adhesion hysteresis on the one hand and lateral excitations of the cantilever on the other. We find that the short range Lennard-Jones part of the atomic interaction alone is sufficient for changing the predominant mechanism. When the long range ionic interaction is switched off, the two damping mechanisms occur with a completely different pattern, which is explained by the energy landscape for the apex atom of the tip. In this case the adhesion hysteresis is always associated with a distinct lateral displacement of the tip. It is shown how this may lead to a systematic shift between the periodic patterns obtained from the frequency and from the damping signal, respectively.

  9. Experimental study of time response of bending deformation of bone cantilevers in an electric field.

    Science.gov (United States)

    Kang, Huimin; Hou, Zhende; Qin, Qing-Hua

    2018-01-01

    Bone is a complex composite material with hierarchical structures and anisotropic mechanical properties. Bone also processes electromechanical properties, such as piezoelectricity and streaming potentials, which termed as stress generated potentials. Furthermore, the electrostrictive effect and flexoelectric effect can also affect electromechanical properties of the bone. In the present work, time responses of bending deflections of bone cantilever in an external electric field are measured experimentally to investigate bone's electromechanical behavior. It is found that, when subjected to a square waveform electric field, a bone cantilever specimen begins to bend and its deflection increases gradually to a peak value. Then, the deflection begins to decrease gradually during the period of constant voltage. To analyze the reasons of the bending response of bone, additional experiments were performed. Experimental results obtained show the following two features. The first one is that the electric polarization, induced in bone by an electric field, is due to the Maxwell-Wagner polarization mechanism that the polarization rate is relatively slow, which leads to the electric field force acted on a bone specimen increase gradually and then its bending deflections increase gradually. The second one is that the flexoelectric polarization effect that resists the electric force to decrease and then leads to the bending deflection of a bone cantilever decrease gradually. It is concluded that the first aspect refers to the organic collagens decreasing the electric polarization rate of the bone, and the second one to the inorganic component influencing the bone's polarization intensity. Copyright © 2017. Published by Elsevier Ltd.

  10. Analysis of local deformation effects in resistive strain sensing of a submicron-thickness AFM cantilever

    Science.gov (United States)

    Adams, Jonathan D.; Schwalb, Christian H.; Winhold, Marcel; Šńukić, Maja; Huth, Michael; Fantner, Georg E.

    2013-05-01

    Incorporating resistive strain-sensing elements into MEMS devices is a long-standing approach for electronic detection of the device deformation. As the need for more sensitivity trends the device dimensions downwards, the size of the strain-sensor may become comparable to the device size, which can have significant impact on the mechanical behaviour of the device. To study this effect, we modelled a submicron-thickness silicon nitride AFM cantilever with strain-sensing element. Using finite element analysis, we calculated the strain in the sensor elements for a deflected cantilever. The sensor element contributes to a local stiffening effect in the device structure which lowers the strain in the sensor. By varying the sensor geometry, we investigated the degree to which this effect impacts the strain. Minimizing the sensor size increases the strain, but the reduction in sensor cross-sectional area increases the resistance and expected sensor noise. The optimal sensor geometry must therefore account for this effect. We used our analysis to optimize geometric variations of nanogranular tunnelling resistor (NTR) strain sensors arranged in a Wheatstone bridge on a silicon nitride AFM cantilever. We varied the dimensions of each sensor element to maintain a constant cross-sectional area but maximize the strain in the sensor element. Through this approach, we expect a 45% increase in strain in the sensor and corresponding 20% increase in the Wheatstone bridge signal. Our results provide an important consideration in the design geometry of resistive strainsensing elements in MEMS devices.

  11. Beam diagnostics

    International Nuclear Information System (INIS)

    Bogaty, J.; Clifft, B.E.; Zinkann, G.P.; Pardo, R.C.

    1995-01-01

    The ECR-PII injector beam line is operated at a fixed ion velocity. The platform high voltage is chosen so that all ions have a velocity of 0.0085c at the PII entrance. If a previous tune configuration for the linac is to be used, the beam arrival time must be matched to the previous tune as well. A nondestructive beam-phase pickup detector was developed and installed at the entrance to the PII linac. This device provides continuous phase and beam current information and allows quick optimization of the beam injected into PII. Bunches traverse a short tubular electrode thereby inducing displacement currents. These currents are brought outside the vacuum interface where a lumped inductance resonates electrode capacitance at one of the bunching harmonic frequencies. This configuration yields a basic sensitivity of a few hundred millivolts signal per microampere of beam current. Beam-induced radiofrequency signals are summed against an offset frequency generated by our master oscillator. The resulting kilohertz difference frequency conveys beam intensity and bunch phase information which is sent to separate processing channels. One channel utilizes a phase locked loop which stabilizes phase readings if beam is unstable. The other channel uses a linear full wave active rectifier circuit which converts kilohertz sine wave signal amplitude to a D.C. voltage representing beam current. A prototype set of electronics is now in use with the detector and we began to use the system in operation to set the arrival beam phase. A permanent version of the electronics system for the phase detector is now under construction. Additional nondestructive beam intensity and phase monitors at the open-quotes Boosterclose quotes and open-quotes ATLASclose quotes linac sections are planned as well as on some of the high-energy beam lines. Such a monitor will be particularly useful for FMA experiments where the primary beam hits one of the electric deflector plates

  12. The Effects of Breathing Behaviour on Crack Growth of a Vibrating Beam

    OpenAIRE

    Liu, Wenguang; Barkey, Mark E.

    2018-01-01

    The effects of breathing behaviour on the dynamic response and crack growth are studied through a cracked cantilever beam. The main goal is to reveal the coupling mechanism of dynamic response and crack growth by employing a plain single-degree-of-freedom (SDOF) lumped system with the breathing crack stiffness and friction damping. The friction damping loss factor is derived by using Coulomb friction model and energy principle. Natural frequency, dynamic stress, dynamic stress intensity facto...

  13. Split-coil-system SULTAN

    International Nuclear Information System (INIS)

    Vecsey, G.

    1992-08-01

    The high field superconductor test facility SULTAN started operation successfully in May 1992. Originally designed for testing full scale conductors for the large magnets of the next generation fusion reactors, the SULTAN facility installed at PSI (Switzerland) was designed as a common venture of three European Laboratories: ENEA (Italy), ECN (Netherlands) and PSI, and built by ENEA and PSI in the framework of the Euratom Fusion Technology Program. Presently the largest facility in the world, with its superconducting split coil system generating 11 Tesla in a 0.6 m bore, it is ready now for testing superconductor samples with currents up to 50 kA at variable cooling conditions. Similar tests can be arranged also for other applications. SULTAN is offered by the European Community as a contribution to the worldwide cooperation for the next step of fusion reactor development ITER. First measurements on conductor developed by CEA (Cadarache) are now in progress. Others like those of ENEA and CERN will follow. For 1993, a test of an Italian 12 TZ model coil for fusion application is planned. SULTAN is a worldwide unique facility marking the competitive presence of Swiss technology in the field of applied superconductivity research. Based on development and design of PSI, the high field Nb 3 Sn superconductors and coils were fabricated at the works of Kabelwerke Brugg and ABB, numerous Swiss companies contributed to the success of this international effort. Financing of the Swiss contribution of SULTAN was made available by NEFF, BEW, BBW, PSI and EURATOM. (author) figs., tabs., 20 refs

  14. Numerical simulation of cantilevered ramp injector flow fields for hypervelocity fuel/air mixing enhancement

    Science.gov (United States)

    Schumacher, Jurgen Christian

    Increasing demand for affordable access to space and high speed terrestrial transport has spawned research interest into various air-breathing hypersonic propulsion systems. Propulsion concepts such as the supersonic combustion ramjet (scramjet) and the shock-induced combustion ramjet (shcramjet) utilize oxygen freely available in the atmosphere and thereby substantially reduce the weight penalty of on-board oxidizer tankage used in rocket based systems. Of key importance to the ultimate success of an air-breathing concept is the ability to efficiently mix the fuel with atmospheric air. In the case of a hypersonic air-breather the challenge is accentuated due to the requirement of supersonic combustion. Flow velocities through the combustor on the order of thousands of meters per second provide the fuel and air with only a brief time to adequately combine. Contemporary mixing augmentation methods to address this issue have focused on fuel injection devices which promote axial vortices to enhance the mixing process. Much research effort has been expended on investigation of ramp injectors for this purpose. The present study introduces a new ramp injector design, based on the conventional ramp injector, dubbed the cantilevered ramp injector. A two-pronged numerical approach was employed to investigate the mixing performance and characteristics of the cantilevered injector consisting of, (1) comparison with conventional designs and (2) a parametric study of various cantilevered injector geometries. A laminar, three-dimensional, multispecies flowsolver was developed in generalized coordinates to solve the Navier-Stokes equations for the flow fields of injected H2 into high-enthalpy air. The scheme consists of an upwind TVD scheme for discretization of the convective fluxes coupled with a semi-implicit LU-SGS scheme for temporal discretization. Through analysis of the numerical solutions, it has been shown that the cantilevered ramp injector is a viable fuel injection

  15. Wave propagation analysis of edge cracked circular beams under impact force.

    Science.gov (United States)

    Akbaş, Şeref Doğuşcan

    2014-01-01

    This paper presents responses of an edge circular cantilever beam under the effect of an impact force. The beam is excited by a transverse triangular force impulse modulated by a harmonic motion. The Kelvin-Voigt model for the material of the beam is used. The cracked beam is modelled as an assembly of two sub-beams connected through a massless elastic rotational spring. The considered problem is investigated within the Bernoulli-Euler beam theory by using energy based finite element method. The system of equations of motion is derived by using Lagrange's equations. The obtained system of linear differential equations is reduced to a linear algebraic equation system and solved in the time domain by using Newmark average acceleration method. In the study, the effects of the location of crack, the depth of the crack, on the characteristics of the reflected waves are investigated in detail. Also, the positions of the cracks are calculated by using reflected waves.

  16. 2-Photon tandem device for water splitting

    DEFF Research Database (Denmark)

    Seger, Brian; Castelli, Ivano Eligio; Vesborg, Peter Christian Kjærgaard

    2014-01-01

    Within the field Of photocatalytic water splitting there are several strategies to achieve the goal of efficient and cheap photocatalytic water splitting. This work examines one particular strategy by focusing on monolithically stacked, two-photon photoelectrochemical cells. The overall aim...... absorption, this is the more difficult side to optimize. Nevertheless, by using TiO2 as a transparent cathode protection layer in conjunction with known H-2 evolution catalysts, protection is clearly feasible for a large bandgap photocathode. This suggests that there may be promising strategies...... for photocatalytic water splitting by using a large bandgap photocathode and a low bandgap photoanode with attached protection layers....

  17. Communication: Tunnelling splitting in the phosphine molecule

    Energy Technology Data Exchange (ETDEWEB)

    Sousa-Silva, Clara; Tennyson, Jonathan; Yurchenko, Sergey N. [Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom)

    2016-09-07

    Splitting due to tunnelling via the potential energy barrier has played a significant role in the study of molecular spectra since the early days of spectroscopy. The observation of the ammonia doublet led to attempts to find a phosphine analogous, but these have so far failed due to its considerably higher barrier. Full dimensional, variational nuclear motion calculations are used to predict splittings as a function of excitation energy. Simulated spectra suggest that such splittings should be observable in the near infrared via overtones of the ν{sub 2} bending mode starting with 4ν{sub 2}.

  18. Splitting Functions at High Transverse Momentum

    CERN Document Server

    Moutafis, Rhea Penelope; CERN. Geneva. TH Department

    2017-01-01

    Among the production channels of the Higgs boson one contribution could become significant at high transverse momentum which is the radiation of a Higgs boson from another particle. This note focuses on the calculation of splitting functions and cross sections of such processes. The calculation is first carried out on the example $e\\rightarrow e\\gamma$ to illustrate the way splitting functions are calculated. Then the splitting function of $e\\rightarrow eh$ is calculated in similar fashion. This procedure can easily be generalized to processes such as $q\\rightarrow qh$ or $g\\rightarrow gh$.

  19. Splitting Strip Detector Clusters in Dense Environments

    CERN Document Server

    Nachman, Benjamin Philip; The ATLAS collaboration

    2018-01-01

    Tracking in high density environments, particularly in high energy jets, plays an important role in many physics analyses at the LHC. In such environments, there is significant degradation of track reconstruction performance. Between runs 1 and 2, ATLAS implemented an algorithm that splits pixel clusters originating from multiple charged particles, using charge information, resulting in the recovery of much of the lost efficiency. However, no attempt was made in prior work to split merged clusters in the Semi Conductor Tracker (SCT), which does not measure charge information. In spite of the lack of charge information in SCT, a cluster-splitting algorithm has been developed in this work. It is based primarily on the difference between the observed cluster width and the expected cluster width, which is derived from track incidence angle. The performance of this algorithm is found to be competitive with the existing pixel cluster splitting based on track information.

  20. Structural basis of photosynthetic water-splitting

    International Nuclear Information System (INIS)

    Photosynthetic water-splitting takes place in photosystem II (PSII), a membrane protein complex consisting of 20 subunits with an overall molecular mass of 350 kDa. The light-induced water-splitting reaction catalyzed by PSII not only converts light energy into biologically useful chemical energy, but also provides us with oxygen indispensible for sustaining oxygenic life on the earth. We have solved the structure of PSII at a 1.9 Å resolution, from which, the detailed structure of the Mn 4 CaO 5 -cluster, the catalytic center for water-splitting, became clear. Based on the structure of PSII at the atomic resolution, possible mechanism of light-induced water-splitting was discussed