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Sample records for electromechanical parameter variations

  1. PARAMETER MATCHING OF INTERNAL COMBUSTION ENGINE AND ELECTROMECHANICAL POWER TRAIN OF WHEEL TRACTOR

    Directory of Open Access Journals (Sweden)

    A. V. Kliuchnikov

    2012-01-01

    Full Text Available The paper considers stepless electromechanical power train of a wheel tractor. Methodology for parameter matching of electromechanical transmission and internal combustion engine for their optimum performance as part of a power wheel tractor unit. 

  2. Impact of electromechanical parameter variations in treatment volume doses and adjacent structures; Impacto da variacao dos parametros eletro-mecanicos nas doses do volume de tratamento e nas estruturas adjacentes

    Energy Technology Data Exchange (ETDEWEB)

    Morais, M.E.; Campos, A.M. [Instituto Nacional do Cancer (INCa), Rio de Janeiro, RJ (Brazil). Programa de Qualidade em Radioterapia]. E-mails: memorais@yahoo.com.br; amcampos@inca.gov.br; Goncalves, J. F. [Instituto de Oncologia e Radioterapia GV, Governador Valadares, MG (Brazil)]. E-mail: joelfgoncalves@yahoo.com.br; Ferreira, M.L. [Centro Radioterapico Gavea, Rio de Janeiro, RJ (Brazil)]. E-mail: mluciaf@yahoo.com

    2003-07-01

    ICRU Report 62 recommends that radiotherapy treatment dose should be prescribed in such a way that the dose to the target volume varies no more than 10%. In order to keep this goal, a very important role is played by the quality assurance (QA) of the treatment unit associated to the high level work of the personnel involved in planning and patient treatment. This paper shows the influence of the main electrical and mechanical linear accelerator parameters: field size, source-skin distance, gantry angle and light x radiation field coincidence in tumor volume and adjacent organ doses. We simulated a cubic tumor and a cubic adjacent critical organ in a cubic phantom and used a 3D Prowess system for planning. The treatment has been simulated for a 6 MV linear accelerator. We simulated two treatment planning: one using all the parameters inside their tolerance limits and another doubling these limits. The final results have show that, if the irradiation machine operates out of the tolerance limits, the dose variation in the planning target volume (PTV) can goes till {+-} 5,8% and in the critical adjacent organ till {+-} 7,7%. Therefore we concluded that, according to the complexity of the treatment, it can be necessary to reduce the tolerance levels advised by the IAEA/TECDOC - 1151. (author)

  3. INFLUENCE OF ARMATURE PARAMETERS OF A LINEAR PULSE ELECTROMECHANICAL CONVERTER ON ITS EFFICIENCY

    Directory of Open Access Journals (Sweden)

    V. F. Bolyukh

    2017-12-01

    Full Text Available Purpose. The evaluation of the effect of armature parameters on the efficiency of a linear pulsed electromechanical converter, taking into account the power, speed, constructive and environmental parameters. Methodology. First, the height of the electrically conductive, coil and ferromagnetic armature of a linear pulse electromechanical converter is determined, at which the highest velocity develops. An integral efficiency index is introduced, which takes into account, in a relative way, the power, speed, energy, electrical and field characteristics of the converter. Variants of the efficiency evaluation strategy are used that take into account the priority of each indicator of a linear pulse electromechanical converter using the appropriate weighting factor in the integral efficiency index. Results. A mathematical model of a linear pulsed electromechanical converter is developed. It is established that as the height of the electroconductive, coil and ferromagnetic armature increases, the force pulse increases. The greatest speed develops with the use of a coil armature, and the smallest with an electroconductive armature. In the converter with coil and ferromagnetic armature, practically the same values of the electrodynamic and electromagnetic force pulse are realized, while in the converter the electrodynamic force is 1.52 times smaller in the converter by the electrically conductive armature. It is established that with all efficiency evaluation strategies, the converter with a coil armature is the most effective, even in spite of its constructive complexity, and the converter with a ferromagnetic armature is the least effective, although it is constructively the simplest. Originality. For the first time, using the integral efficiency index, which takes into account the power, speed, energy, electrical and field indices in a relative way, it is established that with all efficiency evaluation strategies, the converter with a coil armature is

  4. Variation of Parameters in Differential Equations (A Variation in Making Sense of Variation of Parameters)

    Science.gov (United States)

    Quinn, Terry; Rai, Sanjay

    2012-01-01

    The method of variation of parameters can be found in most undergraduate textbooks on differential equations. The method leads to solutions of the non-homogeneous equation of the form y = u[subscript 1]y[subscript 1] + u[subscript 2]y[subscript 2], a sum of function products using solutions to the homogeneous equation y[subscript 1] and…

  5. Monitoring early hydration of reinforced concrete structures using structural parameters identified by piezo sensors via electromechanical impedance technique

    Science.gov (United States)

    Talakokula, Visalakshi; Bhalla, Suresh; Gupta, Ashok

    2018-01-01

    Concrete is the most widely used material in civil engineering construction. Its life begins when the hydration process is activated after mixing the cement granulates with water. In this paper, a non-dimensional hydration parameter, obtained from piezoelectric ceramic (PZT) patches bonded to rebars embedded inside concrete, is employed to monitor the early age hydration of concrete. The non-dimensional hydration parameter is derived from the equivalent stiffness determined from the piezo-impedance transducers using the electro-mechanical impedance (EMI) technique. The focus of the study is to monitor the hydration process of cementitious materials commencing from the early hours and continue till 28 days using single non-dimensional parameter. The experimental results show that the proposed piezo-based non-dimensional hydration parameter is very effective in monitoring the early age hydration, as it has been derived from the refined structural impedance parameters, obtained by eliminating the PZT contribution, and using both the real and imaginary components of the admittance signature.

  6. Electromechanics of a membrane with spatially distributed fixed charges: Flexoelectricity and elastic parameters

    DEFF Research Database (Denmark)

    Loubet, Bastien; Hansen, Per Lyngs; Lomholt, Michael Andersen

    2013-01-01

    We investigate the electrostatic contribution to the lipid membrane mechanical parameters: tension, bending rigidity, spontaneous curvature, and flexocoefficient, using an approach where stress in the membrane is explicitly balanced. Our model includes an applied electrostatic potential as well...

  7. Variation in reproductive and developmental parameters of ...

    African Journals Online (AJOL)

    A study was conducted on ten Botswana cowpea landraces to evaluate their resistance to the cowpea weevil (Callosobruchus maculatus (F) (Coleoptera: Bruchidae). The variations in reproductive and developmental parameters were used to evaluate the landraces for resistance against C. maculatus under laboratory ...

  8. Transduction dependent optimization of electromechanical parameters for electrostatically actuated MEMS/NEMS resonators.

    Science.gov (United States)

    Yan, Jize; Lee, Joshua E-Y; Seshia, Ashwin A

    2010-11-01

    This paper demonstrates an accurate model to predict the overall effective mass in micro- and nanomechanical resonators with non-uniform deformation along the transduction area. The model is verified experimentally through parameter extraction on various types of resonators with an error less than 3% well within the bounds dictated by manufacturing tolerances. Based on the model, an optimization of transduction electrode designs is proposed for micro- and nanomechanical resonators vibrating in the fabrication plane.

  9. Sex variations in the haemorheological parameters of some ...

    African Journals Online (AJOL)

    Sex variations in the haemorheological parameters of some hypertensive Nigerians as compared to hypertensive. ADA Ighoroje, DV Dapper. Abstract. Sex variations in some haemorheological parameters: Haematocrit (Hct), Erythrocyte Sedimentation Rate (ESR), Hemoglobin concentration (Hbc), Fibrinogen concentration ...

  10. 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.

  11. Electromechanical effect in bone

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Marvin Warren [Univ. of Illinois, Urbana-Champaign, IL (United States)

    1977-01-01

    Although bone is piezoelectric, the signal from bent bone cannot be described by the piezoelectric effect if the samples are assumed to be homogeneous. To account for the symmetry properties and z-dependence of the signal from dry bone in cantilever bending, a theory postulating a polarization proportional to the gradient of the stress was proposed. The present work is concerned with a further examination of the applicability of the stress gradient theory to both dry and wet bone. Our measurements on dry bone samples cut from a bovine tibia indicate that the signal is not inversely proportional to the thickness squared, contrary to the prediction of the stress gradient theory for a homogeneous sample. Our measurements show that the moduli responsible for the signal in bent bone vary with position, a finding consistent with some earlier reports that the piezoelectric moduli determined in uniform stress measurements vary with position. These results imply that bone cannot be considered homogeneous. We then show that variations in the piezoelectric moduli can also account for the z-dependence and symmetry properties of the signal observed in bent bone. Since bone is not homogeneous, it is not necessary to introduce the phenomenological stress gradient theory to account for the otherwise anomalous electromechanical effect in bent bone, and we conclude that it is the variations in the piezoelectric moduli that produce the electromechanical effect in bent bone.

  12. Vibroacoustic test plan evaluation: Parameter variation study

    Science.gov (United States)

    Stahle, C. V.; Gongloef, H. R.

    1976-01-01

    Statistical decision models are shown to provide a viable method of evaluating the cost effectiveness of alternate vibroacoustic test plans and the associated test levels. The methodology developed provides a major step toward the development of a realistic tool to quantitatively tailor test programs to specific payloads. Testing is considered at the no test, component, subassembly, or system level of assembly. Component redundancy and partial loss of flight data are considered. Most and probabilistic costs are considered, and incipient failures resulting from ground tests are treated. Optimums defining both component and assembly test levels are indicated for the modified test plans considered. modeling simplifications must be considered in interpreting the results relative to a particular payload. New parameters introduced were a no test option, flight by flight failure probabilities, and a cost to design components for higher vibration requirements. Parameters varied were the shuttle payload bay internal acoustic environment, the STS launch cost, the component retest/repair cost, and the amount of redundancy in the housekeeping section of the payload reliability model.

  13. Lattice variation and thermal parameters of gel grown KDP crystals ...

    Indian Academy of Sciences (India)

    )2SO4) KDP single crystals were grown by the gel method using silica gels. X-ray diffraction data were col- lected for powder samples and used for the estimation of lattice variation and thermal parameters like. Debye–Waller factor ...

  14. Variation in some haematological parameters and levels of selected ...

    African Journals Online (AJOL)

    Variation in some haematological parameters and levels of selected toxic metals in cosmetologists and heavy cosmetic users in Benin City. ... Also, Exposure to cosmetics-borne chemicals through almost all body cavities (skin, nose, eyes and mouth) was observed in both cosmetologistsand heavy cosmetics users (HCU).

  15. Volume variation of Gruneisen parameters of fcc transition metals

    Indian Academy of Sciences (India)

    Unknown

    The results are reasonably good for six metals except for Rh, Ag, Au and Ni when compared with available experimental and other theoretical values. The model requires an appropriate modification for Rh, Ag, Au and Ni. Keywords. fcc transition metals; pseudopotential; Gruneisen parameter; volume variation of Gruneisen.

  16. Variation in biological parameters of cypermethrin resistant and ...

    African Journals Online (AJOL)

    The aim of this survey was to assess the costs of cypermethrin resistance in Helicoverpa armigera strains by using variation in their biological parameters such as fecundity, number of larval slough, development time, weight and survival at each stage of insect development in comparison with susceptible strains. AGB01 and ...

  17. Variational Calculation of Effective Parameters in Random Porous Media

    Science.gov (United States)

    Hristopulos, Dionissios T.; Christakos, George

    1998-03-01

    Effective parameters are used in stochastic hydrology and petroleum engineering as estimates of the coarse-grained behavior of fluid flow and transport. Stochastic effective parameter estimation involves averaging over the local heterogeneity. Explicit evaluation methods are often based on low order perturbation expansions. We obtain more general estimates using a variational scheme that employs auxiliary probability measures. The average over the local fluctuations is evaluated by means of the logarithm transform and the replica trick. The equations satisfied by the effective parameters are obtained variationally from an effective free energy functional. We use this method for the evaluation of the effective permeability of random porous media with Gaussian local fluctuations. The resulting equations are solved explicitly in specific cases, and the results are compared with leading-order perturbation estimates and experimental data. Explicit finite-size expressions are obtained using momentum-space filters. The implications of the finite size behavior for the scaleup problem are discussed.

  18. A variational approach to parameter estimation in ordinary differential equations.

    Science.gov (United States)

    Kaschek, Daniel; Timmer, Jens

    2012-08-14

    Ordinary differential equations are widely-used in the field of systems biology and chemical engineering to model chemical reaction networks. Numerous techniques have been developed to estimate parameters like rate constants, initial conditions or steady state concentrations from time-resolved data. In contrast to this countable set of parameters, the estimation of entire courses of network components corresponds to an innumerable set of parameters. The approach presented in this work is able to deal with course estimation for extrinsic system inputs or intrinsic reactants, both not being constrained by the reaction network itself. Our method is based on variational calculus which is carried out analytically to derive an augmented system of differential equations including the unconstrained components as ordinary state variables. Finally, conventional parameter estimation is applied to the augmented system resulting in a combined estimation of courses and parameters. The combined estimation approach takes the uncertainty in input courses correctly into account. This leads to precise parameter estimates and correct confidence intervals. In particular this implies that small motifs of large reaction networks can be analysed independently of the rest. By the use of variational methods, elements from control theory and statistics are combined allowing for future transfer of methods between the two fields.

  19. Solutions of fractional diffusion equations by variation of parameters method

    Directory of Open Access Journals (Sweden)

    Mohyud-Din Syed Tauseef

    2015-01-01

    Full Text Available This article is devoted to establish a novel analytical solution scheme for the fractional diffusion equations. Caputo’s formulation followed by the variation of parameters method has been employed to obtain the analytical solutions. Following the derived analytical scheme, solution of the fractional diffusion equation for several initial functions has been obtained. Graphs are plotted to see the physical behavior of obtained solutions.

  20. Performance analysis of pin fins with temperature dependent thermal parameters using the variation of parameters method

    Directory of Open Access Journals (Sweden)

    Cihat Arslantürk

    2016-08-01

    Full Text Available The performance of pin fins transferring heat by convection and radiation and having variable thermal conductivity, variable emissivity and variable heat transfer coefficient was investigated in the present paper. Nondimensionalizing the fin equation, the problem parameters which affect the fin performance were obtained. Dimensionless nonlinear fin equation was solved with the variation of parameters method, which is quite new in the solution of nonlinear heat transfer problems. The solution of variation of parameters method was compared with known analytical solutions and some numerical solution. The comparisons showed that the solutions are seen to be perfectly compatible. The effects of problem parameters were investigated on the heat transfer rate and fin efficiency and results were presented graphically.

  1. ANALYSIS THE DIURNAL VARIATIONS ON SELECTED PHYSICAL AND PHYSIOLOGICAL PARAMETERS

    Directory of Open Access Journals (Sweden)

    A. MAHABOOBJAN

    2010-12-01

    Full Text Available The purpose of the study was to analyze the diurnal variations on selected physical and physiological parameters such as speed, explosive power, resting heart rate and breath holding time among college students. To achieve the purpose of this study, a total of twenty players (n=20 from Government Arts College, Salem were selected as subjects To study the diurnal variation of the players on selected physiological and performance variables, the data were collected 4 times a day with every four hours in between the times it from 6.00 to 18.00 hours were selected as another categorical variable. One way repeated measures (ANOVA was used to analyze the data. If the obtained F-ratio was significant, Seheffe’s post-hoc test was used to find out the significant difference if anyamong the paired means. The level of significance was fixed at.05 level. It has concluded that both physical and physiological parameters were significantly deferred with reference to change of temperature in a day

  2. Variational Bayesian Parameter Estimation Techniques for the General Linear Model

    Directory of Open Access Journals (Sweden)

    Ludger Starke

    2017-09-01

    Full Text Available Variational Bayes (VB, variational maximum likelihood (VML, restricted maximum likelihood (ReML, and maximum likelihood (ML are cornerstone parametric statistical estimation techniques in the analysis of functional neuroimaging data. However, the theoretical underpinnings of these model parameter estimation techniques are rarely covered in introductory statistical texts. Because of the widespread practical use of VB, VML, ReML, and ML in the neuroimaging community, we reasoned that a theoretical treatment of their relationships and their application in a basic modeling scenario may be helpful for both neuroimaging novices and practitioners alike. In this technical study, we thus revisit the conceptual and formal underpinnings of VB, VML, ReML, and ML and provide a detailed account of their mathematical relationships and implementational details. We further apply VB, VML, ReML, and ML to the general linear model (GLM with non-spherical error covariance as commonly encountered in the first-level analysis of fMRI data. To this end, we explicitly derive the corresponding free energy objective functions and ensuing iterative algorithms. Finally, in the applied part of our study, we evaluate the parameter and model recovery properties of VB, VML, ReML, and ML, first in an exemplary setting and then in the analysis of experimental fMRI data acquired from a single participant under visual stimulation.

  3. Identification of stiffness variations in supporting substances of a human canine tooth with a bracket-beam-piezoelectric sensor and its electromechanical impedance

    Directory of Open Access Journals (Sweden)

    Hector A. Tinoco

    2017-06-01

    Full Text Available In this paper, an experimental method is described to identify the stiffness variations produced by drillings done in different supporting substances of a human canine tooth. To measure the supporting substances parameters through of a canine, a sensor-actuator system was developed. The sensor-actuator device was composed of a stainless steel bracket bonded to a steel wire attached to two piezoelectric transducers, with a concentrated mass attached to the end of the wire. To excite the device, high frequency voltage (between 5 and 10 KHz was applied through the piezo-transducers, which affects the tooth by means of the vibration of the wire. High frequency mechanical vibrations allowed the appraisal of the mechanical response from the supporting substances. Mechanical responses associated with the stiffness of the support were quantified with the electrical impedance of the piezo-transducers. The device was coupled to the crown of a canine tooth simulating a condition of fixing as in the bone, the tooth was fastened by the root portion inside the supporting substance. Four supporting substances were characterized for the tests. After establishing base values of the stiffness of each supporting substance, the stiffness variations were assessed in two stages (two drillings; these were made perpendicularly to the longitudinal axis of the tooth, Results show that it is possible to assess stiffness variations with the proposed methodology as well as to quantify the stiffness differences, by means of variation indexes.

  4. Anisotropic parameter estimation using velocity variation with offset analysis

    Energy Technology Data Exchange (ETDEWEB)

    Herawati, I.; Saladin, M.; Pranowo, W.; Winardhie, S.; Priyono, A. [Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Jalan Ganesa 10, Bandung, 40132 (Indonesia)

    2013-09-09

    Seismic anisotropy is defined as velocity dependent upon angle or offset. Knowledge about anisotropy effect on seismic data is important in amplitude analysis, stacking process and time to depth conversion. Due to this anisotropic effect, reflector can not be flattened using single velocity based on hyperbolic moveout equation. Therefore, after normal moveout correction, there will still be residual moveout that relates to velocity information. This research aims to obtain anisotropic parameters, ε and δ, using two proposed methods. The first method is called velocity variation with offset (VVO) which is based on simplification of weak anisotropy equation. In VVO method, velocity at each offset is calculated and plotted to obtain vertical velocity and parameter δ. The second method is inversion method using linear approach where vertical velocity, δ, and ε is estimated simultaneously. Both methods are tested on synthetic models using ray-tracing forward modelling. Results show that δ value can be estimated appropriately using both methods. Meanwhile, inversion based method give better estimation for obtaining ε value. This study shows that estimation on anisotropic parameters rely on the accuracy of normal moveout velocity, residual moveout and offset to angle transformation.

  5. Selection of regularization parameter in total variation image restoration.

    Science.gov (United States)

    Liao, Haiyong; Li, Fang; Ng, Michael K

    2009-11-01

    We consider and study total variation (TV) image restoration. In the literature there are several regularization parameter selection methods for Tikhonov regularization problems (e.g., the discrepancy principle and the generalized cross-validation method). However, to our knowledge, these selection methods have not been applied to TV regularization problems. The main aim of this paper is to develop a fast TV image restoration method with an automatic selection of the regularization parameter scheme to restore blurred and noisy images. The method exploits the generalized cross-validation (GCV) technique to determine inexpensively how much regularization to use in each restoration step. By updating the regularization parameter in each iteration, the restored image can be obtained. Our experimental results for testing different kinds of noise show that the visual quality and SNRs of images restored by the proposed method is promising. We also demonstrate that the method is efficient, as it can restore images of size 256 x 256 in approximately 20 s in the MATLAB computing environment.

  6. Electromechanical systems and devices

    CERN Document Server

    Lyshevski, Sergey Edward

    2008-01-01

    ""The book begins with a good, well-written review of some of the basic equations used for electromechanical designs . . . There is very good technical depth to each of the sections in this book, giving the reader the ability to design real systems using the equations and examples from this book . . . aimed at electrical engineering students because it contains homework problems at the end of each chapter and is very instructive for power and electromechanical engineers."" - John J. Shea, in IEEE Electrical Insulation Magazine, March-April 2009, Vol. 25, No. 2

  7. Electromechanical Technician Skills Questionnaire.

    Science.gov (United States)

    Anoka-Hennepin Technical Coll., Minneapolis, MN.

    This document contains test items to measure the job skills of electromechanical technicians. Questions are organized in four sections that cover the following topics: (1) shop math; (2) electricity and electronics; (3) mechanics and machining; and (4) plumbing, heating, ventilation and air conditioning, and welding skills. Questions call for…

  8. Electromechanical Energy Conversion.

    Science.gov (United States)

    LePage, Wilbur R.

    This programed text on electromechanical energy conversion (motors and generators) was developed under contract with the U.S. Office of Education as Number 12 in a series of materials for use in an electrical engineering sequence. It is intended to be used in conjunction with other materials and with other short texts in the series. (DH)

  9. Variation of wave directional spread parameters along the Indian coast

    Digital Repository Service at National Institute of Oceanography (India)

    SanilKumar, V.

    collected at four locations along the East as well as the West side of the Indian coast. The directional spreading parameter was correlated with other characteristic wave parameters, like non-linearity parameter, and directional width. Working empirical...

  10. An electromechanical Ising Hamiltonian.

    Science.gov (United States)

    Mahboob, Imran; Okamoto, Hajime; Yamaguchi, Hiroshi

    2016-06-01

    Solving intractable mathematical problems in simulators composed of atoms, ions, photons, or electrons has recently emerged as a subject of intense interest. We extend this concept to phonons that are localized in spectrally pure resonances in an electromechanical system that enables their interactions to be exquisitely fashioned via electrical means. We harness this platform to emulate the Ising Hamiltonian whose spin 1/2 particles are replicated by the phase bistable vibrations from the parametric resonances of multiple modes. The coupling between the mechanical spins is created by generating two-mode squeezed states, which impart correlations between modes that can imitate a random, ferromagnetic state or an antiferromagnetic state on demand. These results suggest that an electromechanical simulator could be built for the Ising Hamiltonian in a nontrivial configuration, namely, for a large number of spins with multiple degrees of coupling.

  11. Altitudinal variation in metabolic parameters of a small Afrotropical bird.

    Science.gov (United States)

    Thompson, Lindy J; Downs, Colleen T

    2017-10-01

    Of the numerous factors affecting avian metabolic rate, altitude is one of the least studied. We used mass-flow respirometry to measure resting metabolic rate (RMR), evaporative water loss (EWL) and respiratory exchange ratio (RER) in two populations of a small (10-12g) Afrotropical bird, the Cape White-eye (Zosterops virens), in summer and in winter. In total, 51 freshly wild-caught adult Cape White-eyes were measured overnight. Altitude was included as a source of variation in the best approximating models for body mass, whole-animal RMR, RER, whole-animal standard EWL and whole-animal basal EWL. RER was significantly lower in winter, suggesting a greater proportion of lipid oxidation at lower ambient temperatures (T a ). Cape White-eyes were 0.8g heavier at the higher altitude site and 0.5g heavier in winter, suggesting they may have increased their metabolic machinery to cope with cooler temperatures. EWL was generally significantly lower in winter than in summer, suggesting that birds may increase EWL with increasing T a , as the need for evaporative cooling increases. Our results support the argument that the subtle and complex effects of altitude (and ambient temperature) should be taken into account in studies on avian metabolic rate. Of the numerous studies known to affect avian metabolic rate, altitude is one of the least studied. Although trends are not always clear, generally, at higher altitudes, avian metabolic rate increases. There were statistically significant seasonal and altitudinal differences in various physiological parameters of Cape White-eyes. These results highlight the importance of accounting for altitude in studies of avian metabolic rate. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Recent Variations of Fundamental Parameters and Their Implications for Gravitation

    Science.gov (United States)

    Dent, Thomas

    We compare the sensitivity of a recent bound on time variation of the fine structure constant from optical clocks with bounds on time varying fundamental constants from atomic clocks sensitive to the electron-to-proton mass ratio, from radioactive decay rates in meteorites, and from the Oklo natural reactor. Tests of the Weak Equivalence Principle also lead to comparable bounds on present time variations of constants, as well as putting the strongest limits on variations tracking the gravitational potential. For recent time variations, the "winner in sensitivity" depends on possible relations between the variations of different couplings in the standard model of particle physics. WEP tests are currently the most sensitive within scenarios with unification of gauge interactions. A detection of time variation in atomic clocks would favour dynamical dark energy and put strong constraints on the dynamics of a cosmological scalar field.

  13. A TECHNIQUE OF EXPERIMENTAL INVESTIGATIONS OF LINEAR IMPULSE ELECTROMECHANICAL CONVERTERS

    Directory of Open Access Journals (Sweden)

    V.F. Bolyukh

    2017-04-01

    Full Text Available Purpose. Development of a technique of experimental studies linear pulse electromechanical converters parameters, which are used as shock-power devices and electromechanical accelerators, and comparing the experimental results with the calculated indices obtained using the mathematical model. Methodology. Method of experimental investigations of linear electromechanical converter is that the electrical parameters are recorded simultaneously (inductor winding current and mechanical parameters characterizing the power and speed indicators of the joke with actuator. Power indicators are primarily important for shock-power devices, and high velocity - for electromechanical accelerators. Power indices were investigated using piezoelectric sensors, a system of strain sensors, pressure pulsation sensor and high-speed videorecording. Velocity indicators were investigated using a resistive movement sensor which allows to record character of the armature movement with actuating element in each moment. Results. The technique of experimental research, which is the simultaneous recording of electrical and mechanical power and velocity parameters of the linear electromechanical converter pulse, is developed. In the converter as a shock-power device power indicators are recorded using a piezoelectric transducer, strain sensors system, pressure pulsation sensor and high-speed video. The parameters of the inductor winding current pulse, the time lag of mechanical processes in relation to the time of occurrence of the inductor winding current, the average speed of the joke, the magnitude and momentum of electrodynamics forces acting on the plate strikes are experimentally determined. In the converter as an electromechanical accelerator velocity performance recorded using resistive displacement sensors. It is shown that electromechanical converter processes have complex spatial-temporal character. The experimental results are in good agreement with the calculated

  14. Smart electromechanical systems the central nervous system

    CERN Document Server

    Kurbanov, Vugar

    2017-01-01

    This book describes approaches to solving the problems of developing the central nervous system of robots (CNSR) based on smart electromechanical systems (SEMS) modules, principles of construction of the various modules of the central nervous system and variants of mathematical software CNSR in control systems for intelligent robots. It presents the latest advances in theory and practice at the Russian Academy of Sciences. Developers of intelligent robots to solve modern problems in robotics are increasingly addressing the use of the bionic approach to create robots that mimic the complexity and adaptability of biological systems. These have smart electromechanical system (SEMS), which are used in various cyber-physical systems (CPhS), and allow the functions of calculation, control, communications, information storage, monitoring, measurement and control of parameters and environmental parameters to be integrated. The behavior of such systems is based on the information received from the central nervous syst...

  15. Biological variations of hematologic parameters determined by UniCel DxH 800 hematology analyzer.

    Science.gov (United States)

    Zhang, Pianhong; Tang, Huqiang; Chen, Keqing; Chen, Yingying; Xu, Dongsheng

    2013-08-01

    The Coulter DxH 800 hematology analyzer can determine conventional hematologic parameters. It also provides many new hematologic parameters, some of which show potential clinical utility. To study, for the first time, the biological variations of new hematologic parameters and reinvestigate the biological variations of conventional hematologic parameters using the newest Coulter hematology analyzer. Forty adult volunteers (21 women and 19 men) were included. All participants maintained their normal lifestyles. Blood samples were drawn in duplicate by a single experienced phlebotomist and analyzed within 2 hours using a single analyzer. Before each batch analysis, the instrument quality controls were performed using the same lots of reagents. Within-subject and between-subject biological variations for the conventional hematologic parameters were compatible with published data. The analytic variation of the DxH 800 for these parameters appeared smaller. Index of individuality (ratio of within-subject to between-subject biological variation) for all parameters was low. In addition, intraday and interday biological variations of most parameters studied are fairly constant among the population examined. These observations are clinically valuable. Data on within-subject biological variation and analytic precision may be used to generate objective delta-check values for use in quality management. Comparing within-subject and between-subject biological variation on new parameters may allow us to decide the utility of traditional population-based reference ranges. Furthermore, documentation of biological variations of new parameters is an essential prerequisite in the development of any clinical application in the future.

  16. Seasonal variation of meteorological factors on air parameters and ...

    African Journals Online (AJOL)

    The impacts of gas flaring on meteorological factors at Ibeno, Eket, Onna, Esit Eket and Umudike - Nigeria were investigated by measuring air quality parameters. The results show that the mean concentration of air parameters value were below Federal Environmental Protection Agency (FEPA) and United States ...

  17. Variation of plasma parameters in a modified mode of plasma ...

    Indian Academy of Sciences (India)

    grounded target and produce plasma there. The plasma parameters can be controlled by varying the voltages applied to the source magnetic cage and the separation grid of the device. Keywords. Plasma parameters; double plasma device; filament discharge; multidipole magnetic cage. PACS Nos 52.75.Xx; 52.25.

  18. Electromechanical Drivetrain Simulation

    DEFF Research Database (Denmark)

    Gallego Calderon, Juan Felipe

    -MW wind turbines, it is common to find a geared drivetrain, which is the interface between the mechanical and electrical domain. Due to the varying conditions, the drivetrain can suffer accelerated damage reducing the target 20 years life of the turbine. This Ph.D. thesis focuses on the implementation...... of advanced models that consider the electromechanical interaction of the wind turbine structure, namely the main shaft and tower top, along with the gearbox and the generator. This is done with the purpose to advance the integrated analysis of wind turbines; something that is not common until recently...

  19. Variation of semen parameters in healthy medical students due to ...

    African Journals Online (AJOL)

    Straightness can be defined as the linearity of the average path of the sperm5. Its decrease does not necessarily define the fertilization capability of spermatozoa. Apart from variations observed in other semen ... semen may lead to spermatozoa membrane lipid peroxidation and cell death cause by ROS thus explaining the ...

  20. Variation in population structure and life-history parameters of ...

    African Journals Online (AJOL)

    The size and age structures, sex ratio, size- and age-at-sex-change, growth and mortality rate of the protogynous hermaphrodite, steentjie Spondyliosoma emarginatum, were compared to determine the effects on population structure and life-history parameters of exploitation (comparing an unexploited reserve and an ...

  1. Variation of semen parameters in healthy medical students due to ...

    African Journals Online (AJOL)

    Concentration and motility parameters were measured by means of computer assisted semen analysis (CASA) using Sperm Class Analyzer® (Microptic S.L, Madrid, Spain). Results Sperm concentration was significantly decreased in samples donated close to the exam period as well as samples donated during the exam ...

  2. Seasonal variations of water and sediment quality parameters in ...

    African Journals Online (AJOL)

    2012-10-16

    Oct 16, 2012 ... Water samples were collected and their nutrient and chlo- rophyll a concentrations were determined, while various other water quality parameters were measured in situ. Sediment samples were analysed for physical and chemical properties, namely, grain size and organic carbon content. The seasonal.

  3. Seasonal variations of water and sediment quality parameters in ...

    African Journals Online (AJOL)

    Four reed pans were selected and assessed to determine seasonal trends of a variety of water and sediment quality parameters. The study took place over one seasonal cycle from 2008–2009; samples were collected seasonally to account for various hydrological extremes. Water samples were collected and their nutrient ...

  4. Electromechanical interaction in rotordynamics of cage induction motors

    Science.gov (United States)

    Holopainen, Timo P.; Tenhunen, Asmo; Arkkio, Antero

    2005-06-01

    Eccentric rotor motion induces an unbalanced magnetic pull between the rotor and stator of cage induction motors. Recently, a linear parametric model of this eccentricity force due to the arbitrary rotor motion was presented. The purpose of this study is to combine this electromagnetic force model with a simple mechanical rotor model, and further, to demonstrate the rotordynamic response induced by this electromechanical interaction. An electromechanical rotor model is derived on the basis of the Jeffcott rotor with two additional variables for the harmonic currents of the rotor cage. Applying this model, the rotordynamic effects of electromechanical interaction were studied. Three induction motors were used in the numerical examples. The electromechanical parameters of these motors were estimated from the numerical simulations carried out separately. The results obtained show that the electromechanical interaction may decrease the natural frequencies of the rotor, induce additional damping or cause rotordynamic instability. These interaction effects are most significant in motors operating at or near the first bending critical speed. Excluding the potential rotordynamic instability, the numerical results indicate that the electromechanical interaction reduces effectively the unbalance response close to the first bending critical speed.

  5. Electromechanical Drivetrain Simulation

    DEFF Research Database (Denmark)

    Gallego-Calderon, Juan; Branner, Kim; Natarajan, Anand

    2013-01-01

    The work presented in this paper is another step from the DTU Wind Energy efforts to advance understanding of the electromechanical drive-train loads and its interaction with the rest of the components in the wind turbine. The main objective of the PhD is to investigate the modelling and simulation...... of a wind turbine’s drivetrain using an integrated simulation approach where different simulation tools are interconnected. Matlab and HAWC2 are used for this purpose. A contribution is expected to be in the study of the interaction between the mechanical loads in the gearbox due to gear mesh and bearing...... flexibilities, the generator dynamics and the grid, along with the structural loads in the wind turbine. In this paper, two simulation approaches are presented and conclusions are made according to their advantages and disadvantages. The drive-train is described by means of a torsional model composed...

  6. Smart electromechanical systems

    CERN Document Server

    2016-01-01

    This carefully edited book introduces the latest achievements of the scientists of the Russian Academy of Sciences in the field of theory and practice of Smart Electromechanical Systems (SEMS). The book also focuses on methods of designing and modeling of SEMS based on the principles of adaptability, intelligence, biomorphism of parallel kinematics and parallelism in information processing and control computation. The book chapters are dedicated to the following points of interest: - methods of design of SEMS modules and intelligent robots based on them; - synthesis of neural systems of automatic control over SEMS modules; - mathematical and computer modeling of SEMS modules and Cyber Physical Systems based on them; - vitality control and reliability analysis based on logic-and-probabilistic and logic-and-linguistic forecasting; - methods of optimization of SEMS control systems based on mathematical programming methods in ordinal scale and generalized mathematical programming; - information-measuring software...

  7. Diurnal variation of hematology parameters in healthy young males: the Bispebjerg study of diurnal variations

    DEFF Research Database (Denmark)

    Sennels, Henriette P; Jørgensen, Henrik L; Hansen, Anne-Louise S

    2011-01-01

    To evaluate the influence of time of day on the circulating concentrations of 21 hematology parameters.......To evaluate the influence of time of day on the circulating concentrations of 21 hematology parameters....

  8. Thermal effects and beam parameter variations in electron guns

    CERN Document Server

    Khodak, I V; Stepin, D L

    2001-01-01

    The paper described results of research on influence of electrode temperatures and manufacturing tolerance of an electron gun on parameters of an output beam. The Pierce's gun that provides an electron beam with a current of 1.2 A and energy of 25 keV for the S-band technological linac is considered as an example. Numerically calculated parameters of the beam and the temperature distribution in electrodes are presented.It is shown that the acceptable error in a position of electrodes is +- 0.1 mm. This value does not fall outside the limit of thermal deformations and technical abilities for manufacturing guns in a laboratory. The scaling to the area of injectors for compact X-band linacs leads to the tolerance of +-0.01 mm that requires introducing fixing and adjustment elements reducing a thermal insulation of the cathode. However, the calculation and experiment showed that such reducing is negligible even for the modern low temperature thermionic cathodes due to a dominant role of the radiation in the heat ...

  9. Analysis of the variation of range parameters of thermal cameras

    Science.gov (United States)

    Bareła, Jarosław; Kastek, Mariusz; Firmanty, Krzysztof; Krupiński, Michał

    2016-10-01

    Measured range characteristics may vary considerably (up to several dozen percent) between different samples of the same camera type. The question is whether the manufacturing process somehow lacks repeatability or the commonly used measurement procedures themselves need improvement. The presented paper attempts to deal with the aforementioned question. The measurement method has been thoroughly analyzed as well as the measurement test bed. Camera components (such as detector and optics) have also been analyzed and their key parameters have been measured, including noise figures of the entire system. Laboratory measurements are the most precise method used to determine range parameters of a thermal camera. However, in order to obtain reliable results several important conditions have to be fulfilled. One must have the test equipment capable of measurement accuracy (uncertainty) significantly better than the magnitudes of measured quantities. The measurements must be performed in a controlled environment thus excluding the influence of varying environmental conditions. The personnel must be well-trained, experienced in testing the thermal imaging devices and familiar with the applied measurement procedures. The measurement data recorded for several dozen of cooled thermal cameras (from one of leading camera manufacturers) have been the basis of the presented analysis. The measurements were conducted in the accredited research laboratory of Institute of Optoelectronics (Military University of Technology).

  10. diurnal variation in blood parameters in the chicken in the hot

    African Journals Online (AJOL)

    Dr Olaleye

    Twelve adult male chicken of the Nigerian local strain were bled every 3 Hours for 24 hours. Haematological and serum biochemical parameters were measured in the samples collected. Variations in the levels of these parameters throughout the 24 hours were determined. Thirteen out of the parameters measured showed.

  11. Automated system for definition of life-cycle resources of electromechanical equipment

    Science.gov (United States)

    Zhukovskiy, Y.; Koteleva, N.

    2017-02-01

    The frequency of maintenance of electromechanical equipment depends on the plant, which uses and runs this equipment. Very often the maintenance frequency is poorly correlated with the actual state of the electromechanical equipment. Furthermore, traditional methods of diagnosis sometimes cannot work without stopping the process (for example, for equipment located in hard to reach places) and so the maintenance costs are increased. This problem can be solved using the indirect methods of diagnosing of the electromechanical equipment. The indirect methods often use the parameters in the real time and seldom use the parameters of traditional diagnostic methods for determination of the resource of electromechanical equipment. This article is dedicated to developing the structure of a special automated control system. This system must use the big flow of the information about the direct and indirect parameters of the equipment state from plants from different areas of industry and factories which produce the electromechanical equipment.

  12. Effects of variations in structural parameters on performance of switched parasitic arrays

    CSIR Research Space (South Africa)

    Mofolo, MRO

    2011-09-01

    Full Text Available to model random errors in such parameters. The effects of these variations on the performance of the SPA antenna are investigated using a numerical approach. Mutual coupling between the array elements is taken into consideration. The variations are modelled...

  13. Effect of temperature on electromechanical instability of dielectric elastomers

    Science.gov (United States)

    Sheng, Junjie; Chen, Hualing; Li, Bo; Wang, Yongquan; Qiang, Junhua

    2012-04-01

    The electromechanical behavior of dielectric elastomer is strongly affected by the temperature. Very few models accounting for the effects of temperature exist in the literature. A recent experiment showed that the variation of dielectric constant of the most widely used dielectric elastomer (VHB 4910, 3M) according to temperature is relatively significant. In this paper, we develop a thermodynamic model to study the influence of temperature on the instability in dielectric elastomer by involving deformation and temperature-dependent dielectric constant. The results indicate that the increase of temperature could improve the actuation stress and the electromechanical instability of the elastomer.

  14. Needle parameter variation of mature black spruce families displaying a genetic x environment interaction in growth

    Science.gov (United States)

    John E. Major; Kurt H. Johnsen; Debby C. Barsi; Moira Campbell

    2013-01-01

    To examine soil moisture stress, light, and genetic effects on individual needle parameters and investigate total needle contribution to productivity, individual and total needle parameter variation were quantified in 32-year-old black spruce from five crown positions from four full-sib families studied previously for drought tolerance and differential productivity on...

  15. Temperature dependence of electromechanical properties of PLZT x ...

    Indian Academy of Sciences (India)

    The compositions of lead lanthanum zirconate titanate PLZT [Pb(Zr0.57Ti0.43)O3 + at% of La, where = 3, 5, 6, 10 and 12] have been synthesized using mixed oxide route. The temperature dependent electromechanical parameters have been determined using vector impedance spectroscopy (VIS). The charge constant ...

  16. Rhythmic 24-hour variations of frequently used clinical biochemical parameters in healthy young males - The Bispebjerg study of diurnal variations

    DEFF Research Database (Denmark)

    Sennels, Henriette P; Jørgensen, Henrik L; Gøtze, Jens Peter

    2012-01-01

    conditions from 24 healthy young men every third hour through 24 hours, nine time points in total. At each time point, the parameters' concentrations were measured. The data were analyzed by rhythmometric statistical methods and in addition the biological variations were calculated. Results. Significant...... oscillation of melatonin with an amplitude (amp) of 19.84 pg/ml and a peak at 03:34 h confirmed the normal 24-hour rhythms of the participants. Potassium (p...

  17. Dynamic Electromechanical Coupling of Piezoelectric Bending Actuators

    Directory of Open Access Journals (Sweden)

    Mostafa R. A. Nabawy

    2016-01-01

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

  18. Estimation of the location parameter of distributions with known coefficient of variation by record values

    Directory of Open Access Journals (Sweden)

    N. K. Sajeevkumar

    2014-09-01

    Full Text Available In this article, we derived the Best Linear Unbiased Estimator (BLUE of the location parameter of certain distributions with known coefficient of variation by record values. Efficiency comparisons are also made on the proposed estimator with some of the usual estimators. Finally we give a real life data to explain the utility of results developed in this article.

  19. Effects of springs on a pendulum electromechanical energy harvester

    Directory of Open Access Journals (Sweden)

    Arnaud Notué Kadjie

    2014-01-01

    Full Text Available This paper studies a model of energy harvester that consists of an electromechanical pendulum system subjected to nonlinear springs. The output power is analyzed in terms of the intrinsic parameters of the device leading to optimal parameters for energy harvesting. It is found that in an appropriate range of the springs constant, the power attains higher values as compared to the case without springs. The dynamical behavior of the device shows transition to chaos.

  20. Can Simple Soil Parameters Explain Field-Scale Variations in Glyphosate-, Bromoxyniloctanoate-, Diflufenican-, and Bentazone Mineralization?

    DEFF Research Database (Denmark)

    Norgaard, Trine; De Jonge, L. W.; Møldrup, Per

    2015-01-01

    The large spatial heterogeneity in soil physico-chemical and microbial parameters challenges our ability to predict and model pesticide leaching from agricultural land. Microbial mineralization of pesticides is an important process with respect to pesticide leaching since mineralization...... is the major process for the complete degradation of pesticides without generation of metabolites. The aim of our study was to determine field-scale variation in the potential for mineralization of the herbicides glyphosate, bromoxyniloctanoate, diflufenican, and bentazone and to investigate whether...... this variation can be predicted by variations in basic soil parameters. Sixty-five soil samples were sampled from an agricultural, loamy field in Silstrup, Denmark, from a 60 × 165 m rectangular grid. The mineralization potential of the four pesticides was determined using a 96-well microplate 14C...

  1. Variation in selected hematological parameters of captive red-tailed hawks.

    Science.gov (United States)

    Rehder, N B; Bird, D M; Laguë, P C; Mackay, C

    1982-01-01

    Diurnal and winter variations of four hematological parameters were examined in 10 red-tailed hawks (Buteo jamaicensis). The mean values obtained were: 39.4% packed cell volume (PCV); 2.45 X 10(6) erythrocytes (RBC) per mm3 of blood; 5.73 mg of calcium and 1.44 mg of magnesium per 100 ml of plasma. Only the PCV and RBC count showed significant diurnal variation. When the birds were sampled at a set time of day, from November through to February, no significant changes were detected in any of the four parameters. Variation among the birds in RBC count, PCV and calcium concentration was significant on a diurnal basis but over the four month period only the PCV varied significantly.

  2. Reflectance of vegetation, soil, and water. [effects of measurable plant parameters on multispectral signal variations

    Science.gov (United States)

    Wiegand, C. L. (Principal Investigator)

    1974-01-01

    The author has identified the following significant results. Reflectance of crop residues, that are important in reducing wind and water erosion, was more often different from bare soil in band 4 than in bands 5, 6, or 7. The plant parameters leaf area index, plant population, plant cover, and plant height explained 95.9 percent of the variation in band 7 (reflective infrared) digital counts for cotton and 78.2 percent of the variation in digital counts for the combined crops sorghum and corn; hence, measurable plant parameters explain most of the signal variation recorded for corpland. Leaf area index and plant population are both highly correlated with crop yields; since plant population can be readily measured (or possibly inferred from seeding rates), it is useful measurement for calibrating ERTS-type MSS digital data in terms of yield.

  3. A study on parameter variation effects on battery packs for electric vehicles

    Science.gov (United States)

    Zhou, Long; Zheng, Yuejiu; Ouyang, Minggao; Lu, Languang

    2017-10-01

    As one single cell cannot meet power and driving range requirement in an electric vehicle, the battery packs with hundreds of single cells connected in parallel and series should be constructed. The most significant difference between a single cell and a battery pack is cell variation. Not only does cell variation affect pack energy density and power density, but also it causes early degradation of battery and potential safety issues. The cell variation effects on battery packs are studied, which are of great significant to battery pack screening and management scheme. In this study, the description for the consistency characteristics of battery packs was first proposed and a pack model with 96 cells connected in series was established. A set of parameters are introduced to study the cell variation and their impacts on battery packs are analyzed through the battery pack capacity loss simulation and experiments. Meanwhile, the capacity loss composition of the battery pack is obtained and verified by the temperature variation experiment. The results from this research can demonstrate that the temperature, self-discharge rate and coulombic efficiency are the major affecting parameters of cell variation and indicate the dissipative cell equalization is sufficient for the battery pack.

  4. Normal variation in sagittal spinal alignment parameters in adult patients: an EOS study using serial imaging.

    Science.gov (United States)

    Hey, Hwee Weng Dennis; Tan, Kian Loong Melvin; Moorthy, Vikaesh; Lau, Eugene Tze-Chun; Lau, Leok-Lim; Liu, Gabriel; Wong, Hee-Kit

    2018-01-13

    To describe normal variations in sagittal spinal radiographic parameters over an interval period and establish physiological norms and guidelines for which these images should be interpreted. Data were prospectively collected from a continuous series of adult patients with first-episode mild low back pain presenting to a single institution. The sagittal parameters of two serial radiographic images taken 6-months apart were obtained with the EOS® slot scanner. Measured parameters include CL, TK, TL, LL, PI, PT, SS, and end and apical vertebrae. Chi-squared test and Wilcoxon Signed Rank test were used to compare categorical and continuous variables, respectively. Sixty patients with a total of 120 whole-body sagittal X-rays were analysed. Mean age was 52.1 years (SD 21.2). Mean interval between the first and second X-rays was 126.2 days (SD 47.2). Small variations (< 1°) occur for all except PT (1.2°), CL (1.2°), and SVA (2.9 cm). Pelvic tilt showed significant difference between two images (p = 0.035). Subgroup analysis based on the time interval between X-rays, and between the first and second X-rays, did not show significant differences. Consistent findings were found for end and apical vertebrae of the thoracic and lumbar spine between the first and second X-rays for sagittal curve shapes. Radiographic sagittal parameters vary between serial images and reflect dynamism in spinal balancing. SVA and PT are predisposed to the widest variation. SVA has the largest variation between individuals of low pelvic tilt. Therefore, interpretation of these parameters should be patient specific and relies on trends rather than a one-time assessment.

  5. High Frequency Variations of Earth Rotation Parameters from GPS and GLONASS Observations

    Science.gov (United States)

    Wei, Erhu; Jin, Shuanggen; Wan, Lihua; Liu, Wenjie; Yang, Yali; Hu, Zhenghong

    2015-01-01

    The Earth's rotation undergoes changes with the influence of geophysical factors, such as Earth's surface fluid mass redistribution of the atmosphere, ocean and hydrology. However, variations of Earth Rotation Parameters (ERP) are still not well understood, particularly the short-period variations (e.g., diurnal and semi-diurnal variations) and their causes. In this paper, the hourly time series of Earth Rotation Parameters are estimated using Global Positioning System (GPS), Global Navigation Satellite System (GLONASS), and combining GPS and GLONASS data collected from nearly 80 sites from 1 November 2012 to 10 April 2014. These new observations with combining different satellite systems can help to decorrelate orbit biases and ERP, which improve estimation of ERP. The high frequency variations of ERP are analyzed using a de-trending method. The maximum of total diurnal and semidiurnal variations are within one milli-arcseconds (mas) in Polar Motion (PM) and 0.5 milli-seconds (ms) in UT1-UTC. The semidiurnal and diurnal variations are mainly related to the ocean tides. Furthermore, the impacts of satellite orbit and time interval used to determinate ERP on the amplitudes of tidal terms are analyzed. We obtain some small terms that are not described in the ocean tide model of the IERS Conventions 2010, which may be caused by the strategies and models we used or the signal noises as well as artifacts. In addition, there are also small differences on the amplitudes between our results and IERS convention. This might be a result of other geophysical excitations, such as the high-frequency variations in atmospheric angular momentum (AAM) and hydrological angular momentum (HAM), which needs more detailed analysis with more geophysical data in the future. PMID:25635416

  6. High frequency variations of Earth Rotation Parameters from GPS and GLONASS observations.

    Science.gov (United States)

    Wei, Erhu; Jin, Shuanggen; Wan, Lihua; Liu, Wenjie; Yang, Yali; Hu, Zhenghong

    2015-01-28

    The Earth's rotation undergoes changes with the influence of geophysical factors, such as Earth's surface fluid mass redistribution of the atmosphere, ocean and hydrology. However, variations of Earth Rotation Parameters (ERP) are still not well understood, particularly the short-period variations (e.g., diurnal and semi-diurnal variations) and their causes. In this paper, the hourly time series of Earth Rotation Parameters are estimated using Global Positioning System (GPS), Global Navigation Satellite System (GLONASS), and combining GPS and GLONASS data collected from nearly 80 sites from 1 November 2012 to 10 April 2014. These new observations with combining different satellite systems can help to decorrelate orbit biases and ERP, which improve estimation of ERP. The high frequency variations of ERP are analyzed using a de-trending method. The maximum of total diurnal and semidiurnal variations are within one milli-arcseconds (mas) in Polar Motion (PM) and 0.5 milli-seconds (ms) in UT1-UTC. The semidiurnal and diurnal variations are mainly related to the ocean tides. Furthermore, the impacts of satellite orbit and time interval used to determinate ERP on the amplitudes of tidal terms are analyzed. We obtain some small terms that are not described in the ocean tide model of the IERS Conventions 2010, which may be caused by the strategies and models we used or the signal noises as well as artifacts. In addition, there are also small differences on the amplitudes between our results and IERS convention. This might be a result of other geophysical excitations, such as the high-frequency variations in atmospheric angular momentum (AAM) and hydrological angular momentum (HAM), which needs more detailed analysis with more geophysical data in the future.

  7. Sensor fault detection and isolation in doubly-fed induction generators accounting for parameter variations

    Energy Technology Data Exchange (ETDEWEB)

    Galvez-Carrillo, Manuel; Kinnaert, Michel [Dept. of Control Engineering and System Analysis, Universite Libre de Bruxelles (ULB), 50 Av. F.D. Roosevelt, CP 165/55, B-1050 Brussels (Belgium)

    2011-05-15

    A fault detection and isolation (FDI) system for monitoring rotor current sensors in a doubly-fed induction generator (DFIG) for wind turbine applications is presented. The FDI system is designed so that the effect of parameter variations (resistances and inductances) is minimized. The residual generation is based on the generalized observer scheme (GOS) including parameter estimation. A decision system made of a combination of vector CUSUM (Cumulative sum) algorithms is used to process the residual vector and to achieve detection and isolation of incipient (small magnitude) faults. The approach is validated using signals obtained from a simulated vector-controlled DFIG. (author)

  8. Multiphysics simulation electromechanical system applications and optimization

    CERN Document Server

    Dede, Ercan M; Nomura, Tsuyoshi

    2014-01-01

    This book highlights a unique combination of numerical tools and strategies for handling the challenges of multiphysics simulation, with a specific focus on electromechanical systems as the target application. Features: introduces the concept of design via simulation, along with the role of multiphysics simulation in today's engineering environment; discusses the importance of structural optimization techniques in the design and development of electromechanical systems; provides an overview of the physics commonly involved with electromechanical systems for applications such as electronics, ma

  9. Estimations of cosmological parameters from the observational variation of the fine structure constant

    Science.gov (United States)

    Zhai, Zhong-Xu; Liu, Xian-Ming; Zhang, Zhi-Song; Zhang, Tong-Jie

    2013-12-01

    We present constraints on the quintessence scalar field model from observational data of the variation of the fine structure constant obtained from the Keck telescope and VLT. Within the theoretical frame proposed by Bekenstein, the constraints on the parameters of the quintessence scalar field model are obtained. Considering the prior of Ωm0 as WMAP 7 suggests, we obtain various results from different samples. Based on these results, we also calculate the probability density function of the coupling constant ζ. The best-fit values show a consistent relationship between ζ and the different experimental results. In our work, we test two different potential models, namely, the inverse power law potential and the exponential potential. The results show that both the large value of the parameters in the potential and the strong coupling can cause a variation in the fine structure constant.

  10. Adaptive Torque Estimation for an IPMSM with Cross-Coupling and Parameter Variations

    Directory of Open Access Journals (Sweden)

    Dooyoung Yang

    2017-01-01

    Full Text Available This paper presents a new adaptive torque estimation algorithm for an interior permanent magnet synchronous motor (IPMSM with parameter variations and cross-coupling between d- and q-axis dynamics. All cross-coupled, time-varying, or uncertain terms that are not part of the nominal flux equations are included in two equivalent mutual inductances, which are described using the equivalent d- and q-axis back electromotive forces (EMFs. The proposed algorithm estimates the equivalent d- and q-axis back EMFs in a recursive and stability-guaranteed manner, in order to compute the equivalent mutual inductances between the d- and q-axes. Then, it provides a more accurate and adaptive torque equation by adding the correction terms obtained from the computed equivalent mutual inductances. Simulations and experiments demonstrate that torque estimation errors are remarkably reduced by capturing and compensating for the inherent cross-coupling effects and parameter variations adaptively, using the proposed algorithm.

  11. [Periodical changes of various hematological parameters of the human body adaptation and gravitation fields variations].

    Science.gov (United States)

    Gederim, V V; Sokolovskiĭ, V V; Gorshkov, E S; Shapovalov, S N; Troshichev, O A

    2001-01-01

    Monitoring the content of lymphocytes and nucleated neutrophils (observation period 10.5 months) and the determination of the values of leucocytes coefficient and erythrocyte sedimentation rate in chronic patients revealed rhythms of oscillations of these parameters (from 3-5 to 33 days). The coincidence of these rhythms with the rhythms of variations of gravitational field indicates that gravitational field affects the quantitative blood cell composition and the rheological properties of blood.

  12. Temporal variation of tidal parameters in superconducting gravimeter time-series

    Science.gov (United States)

    Meurers, Bruno; Van Camp, Michel; Francis, Olivier; Pálinkáš, Vojtech

    2016-04-01

    Analysing independent 1-yr data sets of 10 European superconducting gravimeters (SG) reveals statistically significant temporal variations of M2 tidal parameters. Both common short-term (2 yr) features are identified in all SG time-series but one. The averaged variations of the amplitude factor are about 0.2‰. The path of load vector variations equivalent to the temporal changes of tidal parameters suggests the presence of an 8.85 yr modulation (lunar perigee). The tidal waves having the potential to modulate M2 with this period belong to the 3rd degree constituents. Their amplitude factors turn out to be much closer to body tide model predictions than that of the main 2nd degree M2, which indicates ocean loading for 3rd degree waves to be less prominent than for 2nd degree waves within the M2 group. These two different responses to the loading suggest that the observed modulation is more due to insufficient frequency resolution of limited time-series rather than to time variable loading. Presently, SG gravity time-series are still too short to prove if time variable loading processes are involved too as in case of the annual M2 modulation known to appear for analysis intervals of less than 1 yr. Whatever the variations are caused by, they provide the upper accuracy limit for earth model validation and permit estimating the temporal stability of SG scale factors and assessing the quality of gravity time-series.

  13. Haematology and Serum Biochemistry Parameters and Variations in the Eurasian Beaver (Castor fiber.

    Directory of Open Access Journals (Sweden)

    Simon J Girling

    Full Text Available Haematology parameters (N = 24 and serum biochemistry parameters (N = 35 were determined for wild Eurasian beavers (Castor fiber, between 6 months - 12 years old. Of the population tested in this study, N = 18 Eurasian beavers were from Norway and N = 17 originating from Bavaria but now living extensively in a reserve in England. All blood samples were collected from beavers via the ventral tail vein. All beavers were chemically restrained using inhalant isoflurane in 100% oxygen prior to blood sampling. Results were determined for haematological and serum biochemical parameters for the species and were compared between the two different populations with differences in means estimated and significant differences being noted. Standard blood parameters for the Eurasian beaver were determined and their ranges characterised using percentiles. Whilst the majority of blood parameters between the two populations showed no significant variation, haemoglobin, packed cell volume, mean cell haemoglobin and white blood cell counts showed significantly greater values (p<0.01 in the Bavarian origin population than the Norwegian; neutrophil counts, alpha 2 globulins, cholesterol, sodium: potassium ratios and phosphorus levels showed significantly (p<0.05 greater values in Bavarian versus Norwegian; and potassium, bile acids, gamma globulins, urea, creatinine and total calcium values levels showed significantly (p<0.05 greater values in Norwegian versus Bavarian relict populations. No significant differences were noted between male and female beavers or between sexually immature (<3 years old and sexually mature (≥3 years old beavers in the animals sampled. With Eurasian beaver reintroduction encouraged by legislation throughout Europe, knowledge of baseline blood values for the species and any variations therein is essential when assessing their health and welfare and the success or failure of any reintroduction program. This is the first study to produce

  14. Evaluation of Electromechanical Systems Dynamically Emulating a Candidate Hydrokinetic Turbine

    OpenAIRE

    Cavagnaro, R.J.; Neely, J.C.; Faÿ, F.-X.; Lopez-Mendia, J.; Rea, J.A.

    2016-01-01

    Implications of conducting hardware-in-the-loop testing of a specific hydrokinetic turbine on controllable motor-generator sets or electromechanical emulation machines (EEMs)are explored. The emulator control dynamic equations are presented, methods for scaling turbine parameters are developed and evaluated, and experimental results are presented from three EEMs programmed to emulate the same vertical-axis fixed-pitch turbine. Although hardware platforms and control implementations varied, re...

  15. Earth rotation parameter and variation during 2005–2010 solved with LAGEOS SLR data

    Directory of Open Access Journals (Sweden)

    Yi Shen

    2015-01-01

    Full Text Available Time series of Earth rotation parameters were estimated from range data measured by the satellite laser ranging technique to the Laser Geodynamics Satellites (LAGEOS-1/2 through 2005 to 2010 using the dynamic method. Compared with Earth orientation parameter (EOP C04, released by the International Earth Rotation and Reference Systems Service, the root mean square errors for the measured X and Y of polar motion (PM and length of day (LOD were 0.24 and 0.25 milliarcseconds (mas, and 0.068 milliseconds (ms, respectively. Compared with ILRSA EOP, the X and Y of PM and LOD were 0.27 and 0.30 mas, and 0.054 ms, respectively. The time series were analyzed using the wavelet transformation and least squares methods. Wavelet analysis showed obvious seasonal and interannual variations of LOD, and both annual and Chandler variations of PM; however, the annual variation could not be distinguished from the Chandler variation because the two frequencies were very close. The trends and periodic variations of LOD and PM were obtained in the least squares sense, and PM showed semi-annual, annual, and Chandler periods. Semi-annual, annual, and quasi-biennial cycles for LOD were also detected. The trend rates of PM in the X and Y directions were 3.17 and −1.60 mas per year, respectively, and the North Pole moved to 26.8°E relative to the crust during 2005–2010. The trend rate of the LOD change was 0.028 ms per year.

  16. Electromechanical converters for electric vehicles

    Science.gov (United States)

    Ambros, T.; Burduniuc, M.; Deaconu, S. I.; Rujanschi, N.

    2018-01-01

    The paper presents the analysis of various constructive schemes of synchronous electromechanical converters with permanent magnets fixed on the rotor and asynchronous with the short-circuit rotor. Various electrical stator winding schemes have also been compared, demonstrating the efficiency of copper utilization in toroidal windings. The electromagnetic calculus of the axial machine has particularities compared to the cylindrical machine, in the paper is presented the method of correlating the geometry of the cylindrical and axial machines. In this case the method and recommendations used in the design of such machines may be used.

  17. Analytical formulations to the method of variation of parameters in terms of universal Y's functions

    Directory of Open Access Journals (Sweden)

    Sharaf M.A.

    2015-01-01

    Full Text Available The method of variation of parameters still has a great interest and wide applications in mathematics, physics and astrodynamics. In this paper, universal functions (the Y's functions based on Goodyear's time transformation formula were used to establish a variation of parameters method which is useful in slightly perturbed two-body initial value problem. Moreover due to its universality, the method avoids the switching among different conic orbits which are commonly occurring in space missions. The position and velocity vectors are written in terms of f and g series. The method is developed analytically and computationally. For the analytical developments, exact literal formulations for the differential system of variation of the epoch state vector are established. Symbolical series solution of the universal Kepler's equation was also established, and the literal analytical expressions of the coefficients of the series are listed in Horner form for efficient and stable evaluation. For computational developments of the method, an efficient algorithm was given using continued fraction theory. Finally, a short note on the method of solution was given just for the reader guidance.

  18. Sensitivity analysis and parameter estimation for distributed hydrological modeling: potential of variational methods

    Science.gov (United States)

    Castaings, W.; Dartus, D.; Le Dimet, F.-X.; Saulnier, G.-M.

    2009-04-01

    Variational methods are widely used for the analysis and control of computationally intensive spatially distributed systems. In particular, the adjoint state method enables a very efficient calculation of the derivatives of an objective function (response function to be analysed or cost function to be optimised) with respect to model inputs. In this contribution, it is shown that the potential of variational methods for distributed catchment scale hydrology should be considered. A distributed flash flood model, coupling kinematic wave overland flow and Green Ampt infiltration, is applied to a small catchment of the Thoré basin and used as a relatively simple (synthetic observations) but didactic application case. It is shown that forward and adjoint sensitivity analysis provide a local but extensive insight on the relation between the assigned model parameters and the simulated hydrological response. Spatially distributed parameter sensitivities can be obtained for a very modest calculation effort (~6 times the computing time of a single model run) and the singular value decomposition (SVD) of the Jacobian matrix provides an interesting perspective for the analysis of the rainfall-runoff relation. For the estimation of model parameters, adjoint-based derivatives were found exceedingly efficient in driving a bound-constrained quasi-Newton algorithm. The reference parameter set is retrieved independently from the optimization initial condition when the very common dimension reduction strategy (i.e. scalar multipliers) is adopted. Furthermore, the sensitivity analysis results suggest that most of the variability in this high-dimensional parameter space can be captured with a few orthogonal directions. A parametrization based on the SVD leading singular vectors was found very promising but should be combined with another regularization strategy in order to prevent overfitting.

  19. Sensitivity analysis and parameter estimation for distributed hydrological modeling: potential of variational methods

    Directory of Open Access Journals (Sweden)

    W. Castaings

    2009-04-01

    Full Text Available Variational methods are widely used for the analysis and control of computationally intensive spatially distributed systems. In particular, the adjoint state method enables a very efficient calculation of the derivatives of an objective function (response function to be analysed or cost function to be optimised with respect to model inputs.

    In this contribution, it is shown that the potential of variational methods for distributed catchment scale hydrology should be considered. A distributed flash flood model, coupling kinematic wave overland flow and Green Ampt infiltration, is applied to a small catchment of the Thoré basin and used as a relatively simple (synthetic observations but didactic application case.

    It is shown that forward and adjoint sensitivity analysis provide a local but extensive insight on the relation between the assigned model parameters and the simulated hydrological response. Spatially distributed parameter sensitivities can be obtained for a very modest calculation effort (~6 times the computing time of a single model run and the singular value decomposition (SVD of the Jacobian matrix provides an interesting perspective for the analysis of the rainfall-runoff relation.

    For the estimation of model parameters, adjoint-based derivatives were found exceedingly efficient in driving a bound-constrained quasi-Newton algorithm. The reference parameter set is retrieved independently from the optimization initial condition when the very common dimension reduction strategy (i.e. scalar multipliers is adopted.

    Furthermore, the sensitivity analysis results suggest that most of the variability in this high-dimensional parameter space can be captured with a few orthogonal directions. A parametrization based on the SVD leading singular vectors was found very promising but should be combined with another regularization strategy in order to prevent overfitting.

  20. Simulations of a epidemic model with parameters variation analysis for the dengue fever

    Science.gov (United States)

    Jardim, C. L. T. F.; Prates, D. B.; Silva, J. M.; Ferreira, L. A. F.; Kritz, M. V.

    2015-09-01

    Mathematical models can be widely found in the literature for describing and analyzing epidemics. The models that use differential equations to represent mathematically such description are specially sensible to parameters involved in the modelling. In this work, an already developed model, called SIR, is analyzed when applied to a scenario of a dengue fever epidemic. Such choice is powered by the existence of useful tools presented by a variation of this original model, which allow an inclusion of different aspects of the dengue fever disease, as its seasonal characteristics, the presence of more than one strain of the vector and of the biological factor of cross-immunity. The analysis and results interpretation are performed through numerical solutions of the model in question, and a special attention is given to the different solutions generated by the use of different values for the parameters present in this model. Slight variations are performed either dynamically or statically in those parameters, mimicking hypothesized changes in the biological scenario of this simulation and providing a source of evaluation of how those changes would affect the outcomes of the epidemic in a population.

  1. An alternating direction algorithm for total variation reconstruction of distributed parameters.

    Science.gov (United States)

    Brás, Nuno B; Bioucas-Dias, J; Martins, Raul C; Serra, A C

    2012-06-01

    Augmented Lagrangian variational formulations and alternating optimization have been adopted to solve distributed parameter estimation problems. The alternating direction method of multipliers (ADMM) is one of such formulations/optimization methods. Very recently, the number of applications of the ADMM, or variants of it, to solve inverse problems in image and signal processing has increased at an exponential rate. The reason for this interest is that ADMM decomposes a difficult optimization problem into a sequence of much simpler problems. In this paper, we use the ADMM to reconstruct piecewise-smooth distributed parameters of elliptical partial differential equations from noisy and linear (blurred) observations of the underlying field. The distributed parameters are estimated by solving an inverse problem with total variation (TV) regularization. The proposed instance of the ADMM solves, in each iteration, an l(2) and a decoupled l(2) - l(1) optimization problems. An operator splitting is used to simplify the treatment of the TV regularizer, avoiding its smooth approximation and yielding a simple yet effective ADMM reconstruction method compared with previously proposed approaches. The competitiveness of the proposed method, with respect to the state-of-the-art, is illustrated in simulated 1-D and 2-D elliptical equation problems, which are representative of many real applications.

  2. Variation of equation of state parameters in the Mg2(Si 1-xSnx) alloys

    KAUST Repository

    Pulikkotil, Jiji Thomas Joseph

    2010-08-03

    Thermoelectric performance peaks up for intermediate Mg2(Si 1-x:Snx) alloys, but not for isomorphic and isoelectronic Mg2(Si1-xGex) alloys. A comparative study of the equation of state parameters is performed using density functional theory, Green\\'s function technique, and the coherent potential approximation. Anomalous variation of the bulk modulus is found in Mg2(Si1-xSn x) but not in the Mg2(Si1-xGex) analogs. Assuming a Debye model, linear variations of the unit cell volume and pressure derivative of the bulk modulus suggest that lattice effects are important for the thermoelectric response. From the electronic structure perspective, Mg2(Si1-xSnx) is distinguished by a strong renormalization of the anion-anion hybridization. © 2010 IOP Publishing Ltd.

  3. Study of gain variation as a function of physical parameters of GEM foil

    CERN Document Server

    Das, Supriya

    2015-01-01

    The ALICE experiment at LHC has planned to upgrade the TPC by replacing the MWPC with GEM based detecting elements to restrict the IBF to a tolerable value. However the variation of the gain as a function of physical parameters of industrially produced large size GEM foils is needed to be studied as a part of the QA procedure for the detector. The size of the electron avalanche and consequently the gain for GEM based detectors depend on the electric field distribution inside the holes. Geometry of a hole plays an important role in defining the electric field inside it. In this work we have studied the variation of the gain as a function of the hole diameters using Garfield++ simulation package.

  4. Study of gain variation as a function of physical parameters of GEM foil

    Energy Technology Data Exchange (ETDEWEB)

    Das, Supriya, E-mail: Supriya.Das@cern.ch

    2016-07-11

    The ALICE experiment at LHC has planned to upgrade the TPC by replacing the MWPC with GEM based detecting elements to restrict the IBF to a tolerable value. However the variation of the gain as a function of physical parameters of industrially produced large size GEM foils is needed to be studied as a part of the QA procedure for the detector. The size of the electron avalanche and consequently the gain for GEM based detectors depend on the electric field distribution inside the holes. Geometry of a hole plays an important role in defining the electric field inside it. In this work we have studied the variation of the gain as a function of the hole diameters using Garfield++ simulation package.

  5. Study of gain variation as a function of physical parameters of GEM foil

    Science.gov (United States)

    Das, Supriya; Alice Collaboration

    2016-07-01

    The ALICE experiment at LHC has planned to upgrade the TPC by replacing the MWPC with GEM based detecting elements to restrict the IBF to a tolerable value. However the variation of the gain as a function of physical parameters of industrially produced large size GEM foils is needed to be studied as a part of the QA procedure for the detector. The size of the electron avalanche and consequently the gain for GEM based detectors depend on the electric field distribution inside the holes. Geometry of a hole plays an important role in defining the electric field inside it. In this work we have studied the variation of the gain as a function of the hole diameters using Garfield++ simulation package.

  6. Testing variational estimation of process parameters and initial conditions of an earth system model

    Directory of Open Access Journals (Sweden)

    Simon Blessing

    2014-03-01

    Full Text Available We present a variational assimilation system around a coarse resolution Earth System Model (ESM and apply it for estimating initial conditions and parameters of the model. The system is based on derivative information that is efficiently provided by the ESM's adjoint, which has been generated through automatic differentiation of the model's source code. In our variational approach, the length of the feasible assimilation window is limited by the size of the domain in control space over which the approximation by the derivative is valid. This validity domain is reduced by non-smooth process representations. We show that in this respect the ocean component is less critical than the atmospheric component. We demonstrate how the feasible assimilation window can be extended to several weeks by modifying the implementation of specific process representations and by switching off processes such as precipitation.

  7. Electromechanical wave imaging for arrhythmias

    Science.gov (United States)

    Provost, Jean; Thanh-Hieu Nguyen, Vu; Legrand, Diégo; Okrasinski, Stan; Costet, Alexandre; Gambhir, Alok; Garan, Hasan; Konofagou, Elisa E.

    2011-11-01

    Electromechanical wave imaging (EWI) is a novel ultrasound-based imaging modality for mapping of the electromechanical wave (EW), i.e. the transient deformations occurring in immediate response to the electrical activation. The correlation between the EW and the electrical activation has been established in prior studies. However, the methods used previously to map the EW required the reconstruction of images over multiple cardiac cycles, precluding the application of EWI for non-periodic arrhythmias such as fibrillation. In this study, new imaging sequences are developed and applied based on flash- and wide-beam emissions to image the entire heart at very high frame rates (2000 fps) during free breathing in a single heartbeat. The methods are first validated by imaging the heart of an open-chest canine while simultaneously mapping the electrical activation using a 64-electrode basket catheter. Feasibility is then assessed by imaging the atria and ventricles of closed-chest, conscious canines during sinus rhythm and during right-ventricular pacing following atrio-ventricular dissociation, i.e., during a non-periodic rhythm. The EW was validated against electrode measurements in the open-chest case, and followed the expected electrical propagation pattern in the closed-chest setting. These results indicate that EWI can be used for the characterization of non-periodic arrhythmias in conditions similar to the clinical setting, in a single heartbeat, and during free breathing.

  8. Variations of 57Fe hyperfine parameters in medicaments containing ferrous fumarate and ferrous sulfate

    Science.gov (United States)

    Oshtrakh, M. I.; Novikov, E. G.; Dubiel, S. M.; Semionkin, V. A.

    2010-04-01

    Several commercially available medicaments containing ferrous fumarate (FeC4H2O4) and ferrous sulfate (FeSO4), as a source of ferrous iron, were studied using a high velocity resolution Mössbauer spectroscopy. A comparison of the 57Fe hyperfine parameters revealed small variations for the main components in both medicaments indicating some differences in the ferrous fumarates and ferrous sulfates. It was also found that all spectra contained additional minor components probably related to ferrous and ferric impurities or to partially modified main components.

  9. A triple quantum dot based nano-electromechanical memory device

    Energy Technology Data Exchange (ETDEWEB)

    Pozner, R.; Lifshitz, E. [Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Solid State Institute, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Peskin, U., E-mail: uri@tx.technion.ac.il [Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Lise Meitner Center for Computational Quantum Chemistry, Technion-Israel Institute of Technology, Haifa 32000 (Israel)

    2015-09-14

    Colloidal quantum dots (CQDs) are free-standing nano-structures with chemically tunable electronic properties. This tunability offers intriguing possibilities for nano-electromechanical devices. In this work, we consider a nano-electromechanical nonvolatile memory (NVM) device incorporating a triple quantum dot (TQD) cluster. The device operation is based on a bias induced motion of a floating quantum dot (FQD) located between two bound quantum dots (BQDs). The mechanical motion is used for switching between two stable states, “ON” and “OFF” states, where ligand-mediated effective interdot forces between the BQDs and the FQD serve to hold the FQD in each stable position under zero bias. Considering realistic microscopic parameters, our quantum-classical theoretical treatment of the TQD reveals the characteristics of the NVM.

  10. Variational estimation of process parameters in a simplified atmospheric general circulation model

    Science.gov (United States)

    Lv, Guokun; Koehl, Armin; Stammer, Detlef

    2016-04-01

    Parameterizations are used to simulate effects of unresolved sub-grid-scale processes in current state-of-the-art climate model. The values of the process parameters, which determine the model's climatology, are usually manually adjusted to reduce the difference of model mean state to the observed climatology. This process requires detailed knowledge of the model and its parameterizations. In this work, a variational method was used to estimate process parameters in the Planet Simulator (PlaSim). The adjoint code was generated using automatic differentiation of the source code. Some hydrological processes were switched off to remove the influence of zero-order discontinuities. In addition, the nonlinearity of the model limits the feasible assimilation window to about 1day, which is too short to tune the model's climatology. To extend the feasible assimilation window, nudging terms for all state variables were added to the model's equations, which essentially suppress all unstable directions. In identical twin experiments, we found that the feasible assimilation window could be extended to over 1-year and accurate parameters could be retrieved. Although the nudging terms transform to a damping of the adjoint variables and therefore tend to erases the information of the data over time, assimilating climatological information is shown to provide sufficient information on the parameters. Moreover, the mechanism of this regularization is discussed.

  11. Quantifying the performance of in vivo portal dosimetry in detecting four types of treatment parameter variations

    Energy Technology Data Exchange (ETDEWEB)

    Bojechko, C.; Ford, E. C., E-mail: eford@uw.edu [Department of Radiation Oncology, University of Washington, 1959 NE Pacific Street, Seattle, Washington 98195 (United States)

    2015-12-15

    Purpose: To quantify the ability of electronic portal imaging device (EPID) dosimetry used during treatment (in vivo) in detecting variations that can occur in the course of patient treatment. Methods: Images of transmitted radiation from in vivo EPID measurements were converted to a 2D planar dose at isocenter and compared to the treatment planning dose using a prototype software system. Using the treatment planning system (TPS), four different types of variability were modeled: overall dose scaling, shifting the positions of the multileaf collimator (MLC) leaves, shifting of the patient position, and changes in the patient body contour. The gamma pass rate was calculated for the modified and unmodified plans and used to construct a receiver operator characteristic (ROC) curve to assess the detectability of the different parameter variations. The detectability is given by the area under the ROC curve (AUC). The TPS was also used to calculate the impact of the variations on the target dose–volume histogram. Results: Nine intensity modulation radiation therapy plans were measured for four different anatomical sites consisting of 70 separate fields. Results show that in vivo EPID dosimetry was most sensitive to variations in the machine output, AUC = 0.70 − 0.94, changes in patient body habitus, AUC = 0.67 − 0.88, and systematic shifts in the MLC bank positions, AUC = 0.59 − 0.82. These deviations are expected to have a relatively small clinical impact [planning target volume (PTV) D{sub 99} change <7%]. Larger variations have even higher detectability. Displacements in the patient’s position and random variations in MLC leaf positions were not readily detectable, AUC < 0.64. The D{sub 99} of the PTV changed by up to 57% for the patient position shifts considered here. Conclusions: In vivo EPID dosimetry is able to detect relatively small variations in overall dose, systematic shifts of the MLC’s, and changes in the patient habitus. Shifts in the

  12. Variations of the ionospheric parameters obtained from ground based measurements of ULF magnetic noise

    Science.gov (United States)

    Ermakova, Elena; Kotik, Dmitry; Bösinger, Tilmann

    2016-07-01

    The dynamics of the amplitude spectra and polarization parameter (epsilon)[1] of magnetic ULF noise were investigated during different seasons and high geomagnetic activity time using the data on the horizontal magnetic components monitoring at mid-latitude (New Life, Russia, 56 N, 46 E) and low-latitude stations (Crete, 35.15 N, 25.20 E). It was found that abrupt changes in the spectral polarization parameters can be linked as with variation of height of maximum and the electron density of the F-layer, and with a change in ionospheric parameters profiles at lower altitudes, for example, with the appearance of sporadic Es-layers and intermediate layers, located between the E and F-layers. It was detected the peculiarities in the daily dynamics of the epsilon parameter at low latitudes: a) the appearance in some cases more complicated than in the mid-latitudes, epsilon structure of the spectrum associated with the presence of two different values of the boundary frequency fB [2]; b) a decreasing of fB near local midnight observed in 70% of cases; c) observation of typical for dark time epsilon spectra after sunrise in the winter season. The numerical calculations of epsilon parameter were made using the IRI-2012 model with setting the models of sporadic and intermediate layers. The results revealed the dependence of the polarization spectra of the intensity and height of such thin layers. The specific changes in the electron density at altitudes of 80-350 km during the recovery phase of strong magnetic storms were defined basing on a comparative analysis of the experimental spectra and the results of the numerical calculations. References. 1. E. N. Ermakova, D. S. Kotik, A. V.Ryabov, A. V.Pershin, T. B.osinger, and Q. Zhou, Studying the variation of the broadband spectral maximum parameters in the natural ULF fields, Radiophysics and Quantum Electronics, Vol. 55, No. 10-11, March, 2013 p. 605-615. 2. T. Bosinger, A. G. Demekhov, E. N. Ermakova, C. Haldoupis and Q

  13. Robust Clamping Force Control of an Electro-Mechanical Brake System for Application to Commercial City Buses

    Directory of Open Access Journals (Sweden)

    Sangjune Eum

    2017-02-01

    Full Text Available This paper proposes a sensor-less robust force control method for improving the control performance of an electro-mechanical brake (EMB which is applicable to commercial city buses. The EMB generates the accurate clamping force commanded by a driver through an independent motor control at each wheel instead of using existing mechanical components. In general, an EMB undergoes parameter variation and a backdrivability problem. For this reason, the cascade control strategy (e.g., force-position cascade control structure is proposed and the disturbance observer is employed to enhance control robustness against model variations. Additionally, this paper proposed the clamping force estimation method for a sensor-less control, i.e., the clamping force observer (CFO. Finally, in order to confirm the performance and effectiveness of a proposed robust control method, several experiments are performed and analyzed.

  14. Micro electro-mechanical heater

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Yunje; Asif, Syed Amanulla Syed; Cyrankowski, Edward; Warren, Oden Lee

    2017-09-12

    A sub-micron scale property testing apparatus including a test subject holder and heating assembly. The assembly includes a holder base configured to couple with a sub-micron mechanical testing instrument and electro-mechanical transducer assembly. The assembly further includes a test subject stage coupled with the holder base. The test subject stage is thermally isolated from the holder base. The test subject stage includes a stage subject surface configured to receive a test subject, and a stage plate bracing the stage subject surface. The stage plate is under the stage subject surface. The test subject stage further includes a heating element adjacent to the stage subject surface, the heating element is configured to generate heat at the stage subject surface.

  15. Electromechanical characterization of selected superconductors

    Science.gov (United States)

    Kopera, L.; Kováč, P.; Melišek, T.

    2008-11-01

    This paper describes the design and performance of a new tension test instrument for measuring stress-strain characteristics of a freestanding sample and critical current degradation of superconducting wires and tapes under variable tension and magnetic fields. The performance of the instrument has been tested at liquid nitrogen and liquid helium temperature up to a tensile force of 1000 N. Stress-strain and Ic-strain characteristics of advanced Bi-2223, Y-123 and MgB2 composite superconductors were measured. The results show the best electromechanical properties for the tapes mechanically reinforced by soldered stainless steel strips. MgB2 tape with a Ti-barrier and Monel sheath is less reinforced due to an apparent softening of these materials during the final annealing at 800 °C/30 min.

  16. Colocalization Estimation Using Graphical Modeling and Variational Bayesian Expectation Maximization: Towards a Parameter-Free Approach.

    Science.gov (United States)

    Awate, Suyash P; Radhakrishnan, Thyagarajan

    2015-01-01

    In microscopy imaging, colocalization between two biological entities (e.g., protein-protein or protein-cell) refers to the (stochastic) dependencies between the spatial locations of the two entities in the biological specimen. Measuring colocalization between two entities relies on fluorescence imaging of the specimen using two fluorescent chemicals, each of which indicates the presence/absence of one of the entities at any pixel location. State-of-the-art methods for estimating colocalization rely on post-processing image data using an adhoc sequence of algorithms with many free parameters that are tuned visually. This leads to loss of reproducibility of the results. This paper proposes a brand-new framework for estimating the nature and strength of colocalization directly from corrupted image data by solving a single unified optimization problem that automatically deals with noise, object labeling, and parameter tuning. The proposed framework relies on probabilistic graphical image modeling and a novel inference scheme using variational Bayesian expectation maximization for estimating all model parameters, including colocalization, from data. Results on simulated and real-world data demonstrate improved performance over the state of the art.

  17. Sensitivity analysis in oxidation ditch modelling: the effect of variations in stoichiometric, kinetic and operating parameters on the performance indices

    NARCIS (Netherlands)

    Abusam, A.A.A.; Keesman, K.J.; Straten, van G.; Spanjers, H.; Meinema, K.

    2001-01-01

    This paper demonstrates the application of the factorial sensitivity analysis methodology in studying the influence of variations in stoichiometric, kinetic and operating parameters on the performance indices of an oxidation ditch simulation model (benchmark). Factorial sensitivity analysis

  18. Immediate effect of simulated sand mining on the variation of bacterial parameters in coastal waters of Kalbadevi Bay, Ratnagiri

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, C.E.G.; Das, A.; Naik, S.S.; Sharma, R.; LokaBharathi, P.A.

    The variation in bacterial parameters of coastal waters and sediments of Kalbadevi Bay, Ratnagiri, Maharashtra, India was examined for immediate response after simulated mining. Sampling was carried out at suction and disturbance points in the water...

  19. Creation of electromechanical device for electric vehicle traction

    Directory of Open Access Journals (Sweden)

    Денис Юрьевич Зубенко

    2016-10-01

    Full Text Available The problems of creation of electromechanical device for electric vehicle traction are considered in the article. The aim of creation this design are the replacement of the internal combustion engine on electromechanical device. For this electromechanical device are constructed model, which describe processes that occur in the electric drive of electromechanical device. Characteristics of the main modes of motion were recorded. The introduction of electromechanical device will reduce the level of emissions and reduce noise in the cities

  20. Total Variation Based Parameter-Free Model for Impulse Noise Removal

    DEFF Research Database (Denmark)

    Sciacchitano, Federica; Dong, Yiqiu; Andersen, Martin Skovgaard

    2017-01-01

    reconstruction problem using a first-order primal-dual algorithm. The proposed model improves the computational efficiency (in the denoising case) and has the advantage of being regularization parameter-free. Our numerical results suggest that the method is competitive in terms of its restoration capabilities......We propose a new two-phase method for reconstruction of blurred images corrupted by impulse noise. In the first phase, we use a noise detector to identify the pixels that are contaminated by noise, and then, in the second phase, we reconstruct the noisy pixels by solving an equality constrained...... total variation minimization problem that preserves the exact values of the noise-free pixels. For images that are only corrupted by impulse noise (i. e., not blurred) we apply the semismooth Newton's method to a reduced problem, and if the images are also blurred, we solve the equality constrained...

  1. Intelligent Controller Design for Quad-Rotor Stabilization in Presence of Parameter Variations

    Directory of Open Access Journals (Sweden)

    Oualid Doukhi

    2017-01-01

    Full Text Available The paper presents the mathematical model of a quadrotor unmanned aerial vehicle (UAV and the design of robust Self-Tuning PID controller based on fuzzy logic, which offers several advantages over certain types of conventional control methods, specifically in dealing with highly nonlinear systems and parameter uncertainty. The proposed controller is applied to the inner and outer loop for heading and position trajectory tracking control to handle the external disturbances caused by the variation in the payload weight during the flight period. The results of the numerical simulation using gazebo physics engine simulator and real-time experiment using AR drone 2.0 test bed demonstrate the effectiveness of this intelligent control strategy which can improve the robustness of the whole system and achieve accurate trajectory tracking control, comparing it with the conventional proportional integral derivative (PID.

  2. Flexoelectric MEMS: towards an electromechanical strain diode

    NARCIS (Netherlands)

    Bhaskar, U.K.; Banerjee, N.; Abdollahi, A.; Solanas, E.; Rijnders, Augustinus J.H.M.; Catalan, G.

    2016-01-01

    Piezoelectricity and flexoelectricity are two independent but not incompatible forms of electromechanical response exhibited by nanoscale ferroelectrics. Here, we show that flexoelectricity can either enhance or suppress the piezoelectric response of the cantilever depending on the ferroelectric

  3. Dimensions of the lumbar spinal canal: variations and correlations with somatometric parameters using CT

    Energy Technology Data Exchange (ETDEWEB)

    Karantanas, A.H. [Department of CT-MRI, Larissa General Hospital (Greece); Zibis, A.H.; Papaliaga, M.; Georgiou, E.; Rousogiannis, S. [Larissa Medical School, University of Thessaly, Larissa (Greece)

    1998-12-01

    The aim of this study was to investigate the correlation of vertebral dimensions with somatometric parameters in patients without clinical symptoms and radiological signs of central lumbar spinal stenosis. One hundred patients presenting with low back pain or sciatica were studied with CT. In each of the L3, L4 and L5 vertebra three slices were taken with the following measurements: 1. Slice through the intervertebral disc: (a) spinal canal area; (b) interarticular diameter; (c) interligamentous diameter. 2. Slice below the vertebral arcus: (a) dural sac area; (b) vertebral body area. 3. Pediculolaminar level: (a) anteroposterior diameter and interpedicular diameter of the spinal canal; (b) spinal canal area; (c) width of the lateral recesses. The Jones-Thomson index was also estimated. The results of the present study showed that there is a statistically significant correlation of height, weight and age with various vertebral indices. The conventional, widely accepted, anteroposterior diameter of 11.5 mm of the lumbar spinal canal is independent of somatometric parameters, and it is the only constant measurement for the estimation of lumbar spinal stenosis with a single value. The present study suggests that there are variations of the dimensions of the lumbar spinal canal and correlations with height, weight and age of the patient. (orig.) With 1 fig., 6 tabs., 24 refs.

  4. Variation of cyclic strain parameters regulates development of elastic modulus in fibroblast/substrate constructs.

    Science.gov (United States)

    Joshi, Sagar D; Webb, Ken

    2008-08-01

    Dynamic mechanical culture systems are a widely studied approach for improving the functional mechanical properties of tissue engineering constructs intended for loading-bearing orthopedic applications such as tendon/ligament reconstruction. The design of effective mechanical stimulation regimes requires a fundamental understanding of the effects of cyclic strain parameters on the resulting construct properties. Toward this end, these studies employed a modular cyclic strain bioreactor system and fibroblast-seeded, porous polyurethane substrates to systematically investigate the effect of varying cyclic strain amplitude, rate, frequency, and daily cycle number on construct mechanical properties. Significant differences were observed in response to variation of all four loading parameters tested. In general, the highest values of elastic modulus within each experimental group were observed at low to intermediate values of the experimental variables tested, corresponding to the low to subphysiological range (2.5% strain amplitude, 25%/s strain rate, 0.1-0.5 Hz frequency, and 7,200-28,800 cycles/day). These studies demonstrate that fibroblasts are sensitive and responsive to multiple characteristics of their mechanical environment, and suggest that systematic optimization of dynamic culture conditions may be useful for the acceleration of construct maturation and mechanical function.

  5. Spatial Variation of the Relationship between PM2.5 Concentrations and Meteorological Parameters in China

    Directory of Open Access Journals (Sweden)

    Gang Lin

    2015-01-01

    Full Text Available Epidemiological studies around the world have reported that fine particulate matter (PM2.5 is closely associated with human health. The distribution of PM2.5 concentrations is influenced by multiple geographic and socioeconomic factors. Using a remote-sensing-derived PM2.5 dataset, this paper explores the relationship between PM2.5 concentrations and meteorological parameters and their spatial variance in China for the period 2001–2010. The spatial variations of the relationships between the annual average PM2.5, the annual average precipitation (AAP, and the annual average temperature (AAT were evaluated using the Geographically Weighted Regression (GWR model. The results indicated that PM2.5 had a strong and stable correlation with meteorological parameters. In particular, PM2.5 had a negative correlation with precipitation and a positive correlation with temperature. In addition, the relationship between the variables changed over space, and the strong negative correlation between PM2.5 and the AAP mainly appeared in the warm temperate semihumid region and northern subtropical humid region in 2001 and 2010, with some localized differences. The strong positive correlation between the PM2.5 and the AAT mainly occurred in the mid-temperate semiarid region, the humid, semihumid, and semiarid warm temperate regions, and the northern subtropical humid region in 2001 and 2010.

  6. Parameter study and optimization for piezoelectric energy harvester for TPMS considering speed variation

    Science.gov (United States)

    Toghi Eshghi, Amin; Lee, Soobum; Lee, Hanmin; Kim, Young-Cheol

    2016-04-01

    In this paper, we perform design parameter study and design optimization for a piezoelectric energy harvester considering vehicle speed variation. Initially, a FEM model using ANSYS is developed to appraise the performance of a piezoelectric harvester in a rotating tire. The energy harvester proposed here uses the vertical deformation at contact patch area from the car weight and centrifugal acceleration. This harvester is composed of a beam which is clamped at both ends and a piezoelectric material is attached on the top of that. The piezoelectric material possesses the 31 mode of transduction in which the direction of applied field is perpendicular to that of the electric field. To optimize the harvester performance, we would change the geometrical parameters of the harvester to obtain the maximum power. One of the main challenges in the design process is obtaining the required power while considering the constraints for harvester weight and volume. These two concerns are addressed in this paper. Since the final goal of this study is the development of an energy harvester with a wireless sensor system installed in a real car, the real time data for varied velocity of a vehicle are taken into account for power measurements. This study concludes that the proposed design is applicable to wireless tire sensor systems.

  7. Analysis of the spatial variation in the parameters of the SWAT model with application in Flanders, Northern Belgium

    Directory of Open Access Journals (Sweden)

    G. Heuvelmans

    2004-01-01

    Full Text Available Operational applications of a hydrological model often require the prediction of stream flow in (future time periods without stream flow observations or in ungauged catchments. Data for a case-specific optimisation of model parameters are not available for such applications, so parameters have to be derived from other catchments or time periods. It has been demonstrated that for applications of the SWAT in Northern Belgium, temporal transfers of the parameters have less influence than spatial transfers on the performance of the model. This study examines the spatial variation in parameter optima in more detail. The aim was to delineate zones wherein model parameters can be transferred without a significant loss of model performance. SWAT was calibrated for 25 catchments that are part of eight larger sub-basins of the Scheldt river basin. Two approaches are discussed for grouping these units in zones with a uniform set of parameters: a single parameter approach considering each parameter separately and a parameter set approach evaluating the parameterisation as a whole. For every catchment, the SWAT model was run with the local parameter optima, with the average parameter values for the entire study region (Flanders, with the zones delineated with the single parameter approach and with the zones obtained by the parameter set approach. Comparison of the model performances of these four parameterisation strategies indicates that both the single parameter and the parameter set zones lead to stream flow predictions that are more accurate than if the entire study region were treated as one single zone. On the other hand, the use of zonal average parameter values results in a considerably worse model fit compared to local parameter optima. Clustering of parameter sets gives a more accurate result than the single parameter approach and is, therefore, the preferred technique for use in the parameterisation of ungauged sub-catchments as part of the

  8. Variations in corneal biomechanical parameters and central corneal thickness during the menstrual cycle.

    Science.gov (United States)

    Goldich, Yakov; Barkana, Yaniv; Pras, Eran; Fish, Alexander; Mandel, Yossi; Hirsh, Ami; Tsur, Nir; Morad, Yair; Avni, Isaac; Zadok, David

    2011-08-01

    To assess variations in the biomechanical properties and central corneal thickness (CCT) throughout the female menstrual cycle. Department of Ophthalmology, Assaf Harofeh Medical Center, Zerifin Israel. Case series. Young healthy women were prospectively recruited. Every participant was assessed at the beginning of the menstrual cycle, at ovulation, and at the end of the cycle. At every time point, corneal hysteresis (CH) and the corneal resistance factor (CRF) were measured with the Ocular Response Analyzer and the CCT was measured with an ultrasonic pachymeter. Twenty-two eyes of 22 women (mean age 19.5 years ± 1.5 [SD]) were included. The CH was statistically significantly decreased at ovulation (10.1 mm Hg) compared with the beginning (11.1 mm Hg, Pcornea was thinnest at the beginning (535 μm) and statistically significantly thicker at ovulation (542 μm, Pbiomechanical parameters significantly varied during the menstrual cycle. The CH and CRF were temporarily decreased at ovulation. The cornea was thinnest at the beginning and thicker at ovulation and at the end of the cycle. Such corneal changes may be important to consider during screening of candidates for laser refractive surgery. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  9. Electromechanical Properties of Bone Tissue.

    Science.gov (United States)

    Regimbal, Raymond L.

    Discrepancies between calculated and empirical properties of bone are thought to be due to a general lack of consideration for the extent and manner(s) with which bone components interact at the molecular level. For a bone component in physiological fluid or whenever two phases are in contact, there is a region between the bulk phases called the electrical double layer which is marked by a separation of electric charges. For the purpose of studying electrical double layer interactions, the method of particle microelectrophoresis was used to characterize bone and its major constituents on the basis of the net charge they bear when suspended in ionic media of physiological relevance. With the data presented as pH versus zeta (zeta ) potential, the figures reveal an isoelectric point (IEP) for bone mineral near pH 8.6, whereas intact and EDTA demineralized bone tissue both exhibit IEPs near pH 5.1. While these data demonstrate the potential for a significant degree of coulombic interaction between the bone mineral and organic constituent double layers, it was also observed that use of inorganic phosphate buffers, as a specific marker for bone mineral, resulted in (1) an immediate reversal, from positive to negative, of the bone mineral zeta potential (2) rendered the zeta potential of intact bone more negative in a manner linearly dependent on both time and temperature and (3) had no affect on demineralized bone (P load for a 3 day period. While it is thus demonstrated that the major inorganic and organic phases of bone are electromechanically coupled, a thermodynamic consideration of the data suggests that the nature of the bond is to preserve mineral and organic phase electroneutralities by participating in electrical double layer interactions. The results are discussed in terms of bone mechanical modeling, electrokinetic properties, aging, tissue-implant compatibility and the etiologies of bone pathologic conditions.

  10. Estimating von Bertalanffy parameters with individual and environmental variations in growth.

    Science.gov (United States)

    Shelton, Andrew O; Mangel, Marc

    2012-01-01

    Variation among individuals is an ubiquitous feature of natural populations. However, the relative roles of intrinsic individual differences and stochastic processes in generating variation remain poorly understood. For somatic growth, identifying the contribution of individual and stochastic processes to observed variation in size has important implications both for basic and applied biology. Here we propose and develop methods for estimating individual variation in growth using size-at-age data. We modify the von Bertalanffy growth model to explicitly incorporate individual, environmental, and stochastic variation and provide analytic expressions for the mean and variance of length-at-age in populations. We use a Bayesian statistical model to estimate individual variation from length-at-age data and apply the model to simulated data to test its efficacy. Although a first step towards understanding individual variation, we demonstrate that estimating individual variation from observational samples is possible and provide a platform for future analytical and statistical developments.

  11. Multidimensional Voice Program (MDVP) and amplitude variation parameters in euphonic adult subjects. Normative study.

    Science.gov (United States)

    Nicastri, M; Chiarella, G; Gallo, L V; Catalano, M; Cassandro, E

    2004-12-01

    The introduction, in the late 70s, of the first digital spectrograph (DSP Sonograph) by Kay Elemetrics has improved the possibilities of spectroacoustic voice analysis in the clinical field. Thanks to the marketing, in 1993, of the Multi Dimensional Voice Program (MDVP) advanced system, it is now possible to analyse 33 quantitative voice parameters which, in turn, allow evaluation of fundamental frequency, amplitude and spectral energy balance and the presence of any sonority gap and diplophony. Despite its potentials, the above-mentioned system is not widely used yet, partly on account of the lack of a standard procedure. Indeed, there are still only a few case reports in the literature taking into consideration prescriptive aspects related both to procedure and analysis. This study aims to provide the results of amplitude perturbation parameter analysis in euphonic adult patients. In our opinion, these are the most significant parameters in determining the severity of a phonation disorder. The study has been carried out on 35 patients (24 female, 11 male, mean age 31.6 years, range 19-59). The voice signal has been recorded using a 4300 B Kay Computer Speech Lab (CSL) supported by a personal computer including a SM48 Shure-Prolog microphone located at a distance of 15 cm and angled at 45 degrees. Input microphone saturation has been adjusted to 6/9 of the CH1 channel. The voice sample consisted in a held /a/ and the analysis has been carried out on the central 3 seconds of the recording. The analysis has been carried out using a 5105 MDVP software version 2.3 and the signal digitalised at a 50 kHz sample rate. In order for the sample to be as free from intensity or frequency changes as possible, each patient underwent a training session (including at least 3 phonation tests) before the recording. The study included only emissions between 55 and 65 dB and with spectrum stability. Environmental noise has constantly been monitored and maintained below 30 dB. Data

  12. The association between atrium electromechanical interval and pericardial fat.

    Directory of Open Access Journals (Sweden)

    Tze-Fan Chao

    Full Text Available OBJECTIVES: Pericardial fat (PCF may induce local inflammation and subsequent structural remodeling of the left atrium (LA. However, the adverse effects of PCF on LA are difficult to be evaluated and quantified. The atrial electromechanical interval determined by transthoracic echocardiogram was shown to be a convenient parameter which can reflect the process of LA remodeling. The goal of the present study was to investigate the association between the electromechanical interval and PCF. METHODS AND RESULTS: A total of 337 patients with mean age of 51.9 ± 9.0 years were enrolled. The electromechanical interval (PA-PDI defined as the time interval from the initiation of the P wave deflection to the peak of the mitral inflow A wave on the pulse wave Doppler imaging was measured for every patient. The amount of PCF was determined by multi-detector computed tomography. The PA-PDI interval was significantly correlated with the amount of PCF (r = 0.641, p value <0.001. Graded prolongation of PA-PDI interval was observed across 3 groups of patients divided according to the tertile values of PCF. The AUC for the PA-PDI interval in predicting an increased amount of PCF (third tertile was 0.796. At a cutoff value of 130 ms identified by the ROC curve, the sensitivity and specificity of PA-PDI interval in identifying patients with a highest tertile of PCF were 63.4% and 85.3%, respectively. CONCLUSIONS: The PA-PDI intervals were longer in patients with an increased amount of PCF. It may be a useful parameter to represent the degree of PCF-related atrial remodeling.

  13. Modal analysis of the electromechanical conversion in piezoelectric ceramic spherical shells.

    Science.gov (United States)

    Aronov, Boris; Brown, David A; Yan, Xiang; Bachand, Corey L

    2011-08-01

    The current study considers piezoelectric ceramic electromechanical transducers utilizing axisymmetric vibrations of complete and incomplete spherical shells. Analysis is focused on generating the modes of vibration that can be employed in the design of multimode unidirectional electroacoustic transducers for underwater applications and on determining the electrode configurations that achieve optimal electromechanical coupling for the different modes of vibration considered. Analytical expressions are presented for the modal and intermodal equivalent parameters characterizing the energy state of the shell vibration. Results of calculation and experimental verification of the resonance frequencies and effective coupling coefficients for different modes of vibration of the complete and incomplete spherical shells are in good agreement.

  14. Diurnal Variation of Intravenous Thrombolysis Rates for Acute Ischemic Stroke and Associated Quality Performance Parameters

    Directory of Open Access Journals (Sweden)

    Björn Reuter

    2017-07-01

    Full Text Available IntroductionBased on data from the Baden-Wuerttemberg stroke registry, we aimed to explore the diurnal variation of acute ischemic stroke (IS care delivery.Materials and methods92,530 IS patients were included, of whom 37,471 (40% presented within an onset-to-door time ≤4.5 h. Daytime was stratified in 3-h time intervals and working vs. non-working hours. Stroke onset and hospital admission time, rate of door-to-neurological examination time ≤30 min, onset-/door-to-imaging time IV thrombolysis (IVT rates, and onset-/door-to-needle time were determined. Multivariable regression models were used stratified by stroke onset and hospital admission time to assess the relationship between IVT rates, quality performance parameters, and daytime. The time interval 0:00 h to 3:00 h and working hours, respectively, were taken as reference.ResultsThe IVT rate of the whole study population was strongly associated with the sleep–wake cycle. In patients presenting within the 4.5-h time window and potentially eligible for IVT stratification by hospital admission time identified two time intervals with lower IVT rates. First, between 3:01 h and 6:00 h (IVT rate 18% and likely attributed to in-hospital delays with the lowest diurnal rate of door-to-neurological examination time ≤30 min and the longest door-to-needle time Second, between 6:01 h and 15:00 h (IVT rate 23–25% compared to the late afternoon and evening hours (IVT rate 27–29% due to a longer onset-to-imaging time and door-to-imaging time. No evidence for a compromised stroke service during non-working hours was observed.ConclusionThe analysis provides evidence that acute IS care is subject to diurnal variation which may affect stroke outcome. An optimization of IS care aiming at constantly high IVT rates over the course of the day therefore appears desirable.

  15. Optimizing Photosynthetic and Respiratory Parameters Based on the Seasonal Variation Pattern in Regional Net Ecosystem Productivity Obtained from Atmospheric Inversion

    Science.gov (United States)

    Chen, Z.; Chen, J.; Zheng, X.; Jiang, F.; Zhang, S.; Ju, W.; Yuan, W.; Mo, G.

    2014-12-01

    In this study, we explore the feasibility of optimizing ecosystem photosynthetic and respiratory parameters from the seasonal variation pattern of the net carbon flux. An optimization scheme is proposed to estimate two key parameters (Vcmax and Q10) by exploiting the seasonal variation in the net ecosystem carbon flux retrieved by an atmospheric inversion system. This scheme is implemented to estimate Vcmax and Q10 of the Boreal Ecosystem Productivity Simulator (BEPS) to improve its NEP simulation in the Boreal North America (BNA) region. Simultaneously, in-situ NEE observations at six eddy covariance sites are used to evaluate the NEE simulations. The results show that the performance of the optimized BEPS is superior to that of the BEPS with the default parameter values. These results have the implication on using atmospheric CO2 data for optimizing ecosystem parameters through atmospheric inversion or data assimilation techniques.

  16. Modeling of dielectric elastomer as electromechanical resonator

    Energy Technology Data Exchange (ETDEWEB)

    Li, Bo, E-mail: liboxjtu@mail.xjtu.edu.cn; Liu, Lei; Chen, Hualing; Jia, Shuhai [School of Mechanical Engineering, Xi' an Jiaotong University, 28 Xianning West Road, Xi' an 710049 (China); State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi' an Jiaotong University, 28 Xianning West Road, Xi' an 710049 (China); Zhang, Junshi [State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi' an Jiaotong University, 28 Xianning West Road, Xi' an 710049 (China); School of Aerospace Engineering, Xi' an Jiaotong University, 28 Xianning West Road, Xi' an 710049 (China); Li, Dichen [School of Mechanical Engineering, Xi' an Jiaotong University, 28 Xianning West Road, Xi' an 710049 (China)

    2014-09-28

    Dielectric elastomers (DEs) feature nonlinear dynamics resulting from an electromechanical coupling. Under alternating voltage, the DE resonates with tunable performances. We present an analysis of the nonlinear dynamics of a DE as electromechanical resonator (DEER) configured as a pure shear actuator. A theoretical model is developed to characterize the complex performance under different boundary conditions. Physical mechanisms are presented and discussed. Chaotic behavior is also predicted, illustrating instabilities in the dynamics. The results provide a guide to the design and application of DEER in haptic devices.

  17. Genetic algorithm for the design of electro-mechanical sigma delta modulator MEMS sensors.

    Science.gov (United States)

    Wilcock, Reuben; Kraft, Michael

    2011-01-01

    This paper describes a novel design methodology using non-linear models for complex closed loop electro-mechanical sigma-delta modulators (EMΣΔM) that is based on genetic algorithms and statistical variation analysis. The proposed methodology is capable of quickly and efficiently designing high performance, high order, closed loop, near-optimal systems that are robust to sensor fabrication tolerances and electronic component variation. The use of full non-linear system models allows significant higher order non-ideal effects to be taken into account, improving accuracy and confidence in the results. To demonstrate the effectiveness of the approach, two design examples are presented including a 5th order low-pass EMΣΔM for a MEMS accelerometer, and a 6th order band-pass EMΣΔM for the sense mode of a MEMS gyroscope. Each example was designed using the system in less than one day, with very little manual intervention. The strength of the approach is verified by SNR performances of 109.2 dB and 92.4 dB for the low-pass and band-pass system respectively, coupled with excellent immunities to fabrication tolerances and parameter mismatch.

  18. A tunable electromechanical Helmholtz resonator

    Science.gov (United States)

    Liu, Fei

    Acoustic liners are used in turbofan engine nacelles for the suppression of engine noise. For a given engine, there are different optimum impedance distributions associated with take-off, cut-back, and approach flight conditions. The impedance of conventional acoustic liners is fixed for a given geometry, and conventional active liner approaches are impractical. This project addresses the need for a tunable impedance through the development of an electromechanical Helmholtz resonator (EMHR). The device consists of a Helmholtz resonator with the standard rigid backplate replaced by a compliant piezoelectric composite. Analytical models (i.e., a lumped element model (LEM) and a transfer matrix (TM) representation of the EMHR) are developed to predict the acoustic behavior of the EMHR. The EMHR is experimentally investigated using the standard two-microphone method (TMM). The measurement results validate both the LEM and the TM of the EMHR. Good agreement between predicted and measured impedance is obtained. Short- and open-circuit loads define the limits of the tuning range using resistive and capacitive loads. There is approximately a 9% tuning limit under these conditions for the non-optimized resonator configuration studied. Inductive shunt loads result in a 3 degree-of-freedom (DOF) system and an enhanced tuning range of over 47% that is not restricted by the short- and open-circuit limits. Damping coefficient measurements for a piezoelectric backplate in a vacuum chamber are performed and indicate that the damping is dominated by structural damping losses. A Pareto optimization design based on models of the EMHR is performed with non-inductive loads. The EMHR with non-inductive loads has 2DOF and two resonant frequencies. The tuning ranges of the two resonant frequencies of the EMHR with non-inductive loads cannot be optimized simultaneously, so a trade-off (Pareto solution) must be reached. The Pareto solution shows how design trade-offs can be used to satisfy

  19. Biological variations of leukocyte numerical and morphologic parameters determined by UniCel DxH 800 hematology analyzer.

    Science.gov (United States)

    Tang, Huqiang; Jing, Jiyong; Bo, Dandan; Xu, Dongsheng

    2012-11-01

    The Coulter DxH 800 hematology analyzer can determine leukocyte numerical parameters (total leukocyte counts and differentials). It also measures intrinsic biophysical properties of these cells in their near-native state. These morphologic measurements are known as cell population data (CPD). To study, for the first time, the biological variations of morphologic parameters or CPD and reinvestigate numerical parameters using the newest Coulter hematology analyzer. Design.-Forty adult volunteers (21 women, 19 men) were included. All participants maintained their normal lifestyles. Blood samples were drawn in duplicate by a single experienced phlebotomist and analyzed within 2 hours using a single analyzer. Before each batch analysis, the instrument quality controls were performed using the same lots of reagents. Within-subject (CV(I)) and between-subjects (CV(G)) biological variations for numerical parameters are smaller than previously reported. Cell population data have much smaller overall CV(I) and CV(G) compared to numerical parameters, suggesting that these parameters are less variable around the homeostatic set point intraindividually and interindividually. Index of individuality (ratio of CV(I)/CV(G)) for CPD was low. In addition, intraday and interday biological variations of all parameters are fairly constant. These observations are clinically valuable. Data on CV(I) and analytical precision may be used to generate objective delta-check values for use in quality management. Comparing CV(I) and CV(G) on CPD may allow us to decide the utility of traditional population-based reference ranges. Documentation of CPD on biological variations is an essential prerequisite in the development of any new application clinically.

  20. Variation of protein MWD parameters and their associations with free asparagine concentration and quality characteristics in hard red spring wheat

    Science.gov (United States)

    This research was performed to determine variation of protein molecular weight distribution (MWD) parameters using size exclusion HPLC and their associations with quality characteristics and free asparagine concentration (FAC) using eleven hard red spring (HRS) wheat genotypes grown at three locatio...

  1. Variation in the Kozak sequence of WNT16 results in an increased translation and is associated with osteoporosis related parameters

    DEFF Research Database (Denmark)

    Hendrickx, Gretl; Boudin, Eveline; Fijałkowski, Igor

    2014-01-01

    on osteoporosis related parameters. Hereto, we performed a WNT16 candidate gene association study in a population of healthy Caucasian men from the Odense Androgen Study (OAS). Using HapMap, five tagSNPs and one multimarker test were selected for genotyping to cover most of the common genetic variation...

  2. Genetic parameters for within-litter variation in piglet birth weight and change in within-litter variation during suckling.

    Science.gov (United States)

    Damgaard, L H; Rydhmer, L; Løvendahl, P; Grandinson, K

    2003-03-01

    The objective of this study was to ascertain whether maternal additive genetic variance exists for within-litter variation in birth weight and for change in within-litter variation in piglet weight during suckling. A further objective was to estimate maternal genetic correlations of these two traits with mortality, birth weight, growth, and number of piglets born alive. Data were obtained from Lövsta research station, Swedish University of Agricultural Sciences, and included 22,521 piglets born in 2,003 litters by 1,074 Swedish Yorkshire sows. No cross fostering was used in the herd. The following seven traits were analysed in a multivariate animal (sow) model: number of piglets born alive, within-litter SD in birth weight, within-litter SD in piglet weight at 3 wk of age, mean weight at birth, mean weight at 3 wk of age, proportion of stillborn piglets, and proportion of dead piglets during suckling. Maternal genetic variance for the change in within-litter SD in piglet weight during suckling was assessed from the estimated additive genetic covariance components by conditioning on within-litter SD in birth weight. Similarly, mean growth of piglets during suckling was assessed from the additive genetic covariance components by conditioning on mean weight at birth. The heritability for within-litter SD in birth weight was 0.08 and 0.06 for within-litter SD in piglet weight at 3 wk. The genetic correlation between these two traits was 0.71. Little maternal genetic variance was found for the change in within-litter SD in piglet weight during suckling, and opportunity for genetic improvement of this trait by selective breeding seems limited. The genetic correlation of within-litter SD in birth weight with proportion of dead piglets during suckling was 0.25 and of within-litter SD in birth weight with mean growth of piglets was -0.31. The maternal genetic variance and heritability found for within-litter SD in birth weight indicates that genetic improvement of this

  3. An Electromechanical Model of Neuronal Dynamics using Hamilton's Principle

    Directory of Open Access Journals (Sweden)

    Corina Stefania Drapaca

    2015-07-01

    Full Text Available Damage of the brain may be caused by mechanical loads such as penetration, blunt force, shock loading from blast, and by chemical imbalances due to neurological diseases and aging that trigger not only neuronal degeneration but also changes in the mechanical properties of brain tissue. An understanding of the interconnected nature of the electro-chemo-mechanical processes that result in brain damage and ultimately loss of functionality is currently lacking. While modern mathematical models that focus on how to link brain mechanics to its biochemistry are essential in enhancing our understanding of brain science, the lack of experimental data required by these models as well as the complexity of the corresponding computations render these models hard to use in clinical applications. In this paper we propose a unified variational framework for the modeling of neuronal electromechanics. We introduce a constrained Lagrangian formulation that takes into account Newton's law of motion of a linear viscoelastic Kelvin-Voigt solid-state neuron as well as the classic Hodgkin-Huxley equations of the electronic neuron. The system of differential equations describing neuronal electromechanics is obtained by applying Hamilton's principle. Numerical simulations of possible damage dynamics in neurons will be presented.

  4. Electromechanical coupling in piezoelectric nanobeams due to the flexoelectric effect

    Science.gov (United States)

    Zhou, Z. D.; Yang, C. P.; Su, Y. X.; Huang, R.; Lin, X. L.

    2017-09-01

    The flexoelectric effect is a coupling of polarization and strain gradient, which exists in a wide variety of materials and may lead to strong size-dependent properties at the nanoscale. Based on an extension to the classical beam model, this paper investigates the electromechanical coupling response of piezoelectric nanobeams with different electrical boundary conditions including the effect of flexoelectricity. The electric Gibbs free energy and the variational principle are used to derive the governing equations with three types of electrical boundary conditions. Closed-form solutions are obtained for static bending of cantilever beams. The results show that the normalized effective stiffness increases with decreasing beam thickness in the open circuit electrical boundary conditions with or without surface electrodes. The induced electric potential due to the flexoelectric effect is obtained under the open circuit conditions, which may be important for sensing or energy harvesting applications. An intrinsic thickness depending on the material properties is identified for the maximum induced electric potential. The present results also show that flexoelectricity has a more significant effect on the electroelastic responses than piezoelectricity at the nanoscale. Our analysis in the present study can be useful for understanding of the electromechanical coupling in nanobeams with flexoelectricity.

  5. Advanced Controllers for Electromechanical Motion Systems

    NARCIS (Netherlands)

    Nguyen, Duy Cuong

    2008-01-01

    The aim of this research is to develop advanced controllers for electromechanical motion systems. In order to increase efficiency and reliability, these control systems are required to achieve high performance and robustness in the face of model uncertainty, measurement noise, and reproducible

  6. Electromechanical systems generating constant frequency alternating current

    Directory of Open Access Journals (Sweden)

    Т.А. Мазур

    2008-01-01

    Full Text Available  In the article we consider the usage of electromechanical drivers of constant speed rotation, which is based on many stepped electrodynamic reduction unit, in onboard main systems of electric supply of alternative current with constant frequency.

  7. Method of Data storing, collection and aggregation for definition of life-cycle resources of electromechanical equipment

    Science.gov (United States)

    Zhukovskiy, Y.; Koteleva, N.

    2017-10-01

    Analysis of technical and technological conditions for the emergence of emergency situations during the operation of electromechanical equipment of enterprises of the mineral and raw materials complex shows that when developing the basis for ensuring safe operation, it is necessary to take into account not only the technical condition, but also the non-stationary operation of the operating conditions of equipment, and the nonstationarity of operational operating parameters of technological processes. Violations of the operation of individual parts of the machine, not detected in time, can lead to severe accidents at work, as well as to unplanned downtime and loss of profits. That is why, the issues of obtaining and processing Big data obtained during the life cycle of electromechanical equipment, for assessing the current state of the electromechanical equipment used, timely diagnostics of emergency and pre-emergency modes of its operation, estimating the residual resource, as well as prediction the technical state on the basis of machine learning are very important. This article is dedicated to developing the special method of data storing, collection and aggregation for definition of life-cycle resources of electromechanical equipment. This method can be used in working with big data and can allow extracting the knowledge from different data types: the plants’ historical data and the factory historical data. The data of the plants contains the information about electromechanical equipment operation and the data of the factory contains the information about a production of electromechanical equipment.

  8. Patterns of variation in reproductive parameters in Eurasian lynx (Lynx lynx)

    OpenAIRE

    Nilsen, Erlend B; John D C Linnell; Odden, John; Samelius, Gustaf; Andrén, Henrik

    2011-01-01

    Detailed knowledge of the variation in demographic rates is central for our ability to understand the evolution of life history strategies and population dynamics, and to plan for the conservation of endangered species. We studied variation in reproductive output of 61 radio-collared Eurasian lynx females in four Scandinavian study sites spanning a total of 223 lynx-years. Specifically, we examined how the breeding proportion and litter size varied among study areas and age classes (2-year-ol...

  9. Impacts of meteorological parameters and emissions on decadal, interannual, and seasonal variations of atmospheric black carbon in the Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    Yu-Hao Mao

    2016-09-01

    Full Text Available We quantified the impacts of variations in meteorological parameters and emissions on decadal, interannual, and seasonal variations of atmospheric black carbon (BC in the Tibetan Plateau for 1980–2010 using a global 3-dimensional chemical transport model driven by the Modern Era Retrospective-analysis for Research and Applications (MERRA meteorological fields. From 1980 to 2010, simulated surface BC concentrations and all-sky direct radiative forcing at the top of the atmosphere due to atmospheric BC increased by 0.15 μg m−3 (63% and by 0.23 W m−2 (62%, respectively, averaged over the Tibetan Plateau (75–105°E, 25–40°N. Simulated annual mean surface BC concentrations were in the range of 0.24–0.40 μg m−3 averaged over the plateau for 1980–2010, with the decadal trends of 0.13 μg m−3 per decade in the 1980s and 0.08 in the 2000s. The interannual variations were −5.4% to 7.0% for deviation from the mean, 0.0062 μg m−3 for mean absolute deviation, and 2.5% for absolute percent departure from the mean. Model sensitivity simulations indicated that the decadal trends of surface BC concentrations were mainly driven by changes in emissions, while the interannual variations were dependent on variations of both meteorological parameters and emissions. Meteorological parameters played a crucial role in driving the interannual variations of BC especially in the monsoon season.

  10. Structural Health Monitoring Using High-Frequency Electromechanical Impedance Signatures

    Directory of Open Access Journals (Sweden)

    Wei Yan

    2010-01-01

    Full Text Available An overview of recent advances in electromechanical impedance- (EMI- based structural health monitoring is presented in this paper. The basic principle of the EMI method is to use high-frequency excitation to sense the local area of a structure. Changes in impedance indicate changes in the structure, which in turn indicate that damages appear. An accurate EMI model based on the method of reverberation-ray matrix is introduced to correlate changes in the signatures to physical parameters of structures for damage detection. Comparison with other numerical results and experimental data validates the present model. A brief remark of the feasibility of implementing the EMI method is considered and the effects of some physical parameters on EMI technique are also discussed.

  11. Unimodal optimal passive electromechanical damping of elastic structures

    Science.gov (United States)

    Ben Mekki, O.; Bourquin, F.; Maceri, F.; Merliot, E.

    2013-08-01

    In this paper, a new electromechanical damper is presented and used, made of a pendulum oscillating around an alternator axis and connected by a gear to the vibrating structure. In this way, the mechanical energy of the oscillating mass can be transformed into electrical energy to be dissipated when the alternator is branched on a resistor. This damping device is intrinsically non-linear, and the problem of the optimal parameters and of the best placement of this damper on the structure is studied. The optimality criterion chosen here is the maximum exponential time decay rate (ETDR) of the structural response. This criterion leads to new design formulas. The case of a bridge under construction is considered and the analytical results are compared with experimental ones, obtained on a mock-up made of a vertical tower connected to a free-end horizontal beam, to simulate the behavior of a cable-stayed bridge during the erection phase. Up to three electromechanical dampers are placed in order to study the multi-modal damping. The satisfactory agreement between the theoretical model and the experiments suggests that a multi-modal passive damping of electromagnetic type could be effective on lightweight flexible structures, when dampers are suitably placed.

  12. System-Level Design Considerations for Carbon Nanotube Electromechanical Resonators

    Directory of Open Access Journals (Sweden)

    Christian Kauth

    2013-01-01

    Full Text Available Despite an evermore complete plethora of complex domain-specific semiempirical models, no succinct recipe for large-scale carbon nanotube electromechanical systems design has been formulated. To combine the benefits of these highly sensitive miniaturized mechanical sensors with the vast functionalities available in electronics, we identify a reduced key parameter set of carbon nanotube properties, nanoelectromechanical system design, and operation that steers the sensor’s performance towards system applications, based on open- and closed-loop topologies. Suspended single-walled carbon nanotubes are reviewed in terms of their electromechanical properties with the objective of evaluating orders of magnitude of the electrical actuation and detection mechanisms. Open-loop time-averaging and 1ω or 2ω mixing methods are completed by a new 4ω actuation and detection technique. A discussion on their extension to closed-loop topologies and system applications concludes the analysis, covering signal-to-noise ratio, and the capability to spectrally isolate the motional information from parasitical feedthrough by contemporary electronic read-out techniques.

  13. Parameter selection in limited data cone-beam CT reconstruction using edge-preserving total variation algorithms

    Science.gov (United States)

    Lohvithee, Manasavee; Biguri, Ander; Soleimani, Manuchehr

    2017-12-01

    There are a number of powerful total variation (TV) regularization methods that have great promise in limited data cone-beam CT reconstruction with an enhancement of image quality. These promising TV methods require careful selection of the image reconstruction parameters, for which there are no well-established criteria. This paper presents a comprehensive evaluation of parameter selection in a number of major TV-based reconstruction algorithms. An appropriate way of selecting the values for each individual parameter has been suggested. Finally, a new adaptive-weighted projection-controlled steepest descent (AwPCSD) algorithm is presented, which implements the edge-preserving function for CBCT reconstruction with limited data. The proposed algorithm shows significant robustness compared to three other existing algorithms: ASD-POCS, AwASD-POCS and PCSD. The proposed AwPCSD algorithm is able to preserve the edges of the reconstructed images better with fewer sensitive parameters to tune.

  14. Variation of the critical power model parameters in response to kayak training

    Directory of Open Access Journals (Sweden)

    Alexandre Hideki Okano

    2006-08-01

    Full Text Available This study proposed to verify the sensibility of the critical power model parameters in response to training load variation during a kayaking competitive season. Eleven young male kayakers participated of this study. They were evaluated at the end of each of three mesocycles, as follows: (M1 characteristically aerobic; (M2 characteristically aerobic-anaerobic and; (M3 characteristically anaerobic and velocity, just before competition. Critical velocity (CV and kayaking anaerobic capacity (ACkayak were estimated from the results of three distance tests (500, 1,000 e 1,800 m covered in the minimal possible time. The ACkayak did not change after the three mesocycles (M1: 91.4 ± 32.0 m; M2: 89.,0 ± 50.8 m e; M3: 74.0 ± 44.2 m. In contrast, CV improved from M1 (3.19 ± 0.28 m.s-1 to M2 (3.33 ± 0.28 m.s-1, and became stable in M3 (3.32 ± 0.19 m.s-1. The results indicated that CV is sensible to training effects, and it can be used to control for aerobic training adaptations. RESUMO O objetivo deste estudo foi averiguar a sensibilidade dos parâmetros do modelo de potência crítica, em resposta às oscilações nas cargas de treinamento, ao longo de uma temporada competitiva de canoagem. Participaram deste estudo 11 canoístas jovens, do sexo masculino, os quais foram avaliados ao final de cada um de três mesociclos seguidos, sendo: (M1 após mesociclo de característica aeróbia; (M2 após mesociclo de característica mista aeróbia-anaeróbia e; (M3 após mesociclo de característica anaeróbia e de velocidade, o qual antecedia a competição. Nos três momentos, foram determinadas a velocidade crítica (VCrit e a capacidade anaeróbia da canoagem (CACanoagem por meio de três distância fixas (500, 1.000 e 1.800 m, percorridas no menor tempo possível. A CACanoagem não foi alterada ao longo dos três mesociclos estudados (M1: 91,4 ± 32,0 m; M2: 89,0 ± 50,8 m e; M3: 74,0 ± 44,2 m. Já a VCrit foi melhorada de M1 (3,19 ± 0,28 m/s para M2 (3

  15. Gaussian Mixture Density based Analytical Model of Noise Induced Variation in Key Parameter of Electronically Tunable Device

    Directory of Open Access Journals (Sweden)

    Rawid Banchuin

    2015-03-01

    Full Text Available In this research, the Gaussian mixture density based analytical model of variation in key parameter of electronically tunable device has been originally proposed. The proposed model is applicable to any electronically tunable device with its tuning variable has been affected by any kind of noise with arbitrary parameters. It has been found from the verification by using different electronically tunable device based empirical distributions and the Kolmogorov-Smirnov tests that this novel model is very accurate. So, it has been found to be a convenient mathematical tool for the analysis and design of various electronically tunable device based circuits.

  16. Electrical Characterization of 4H-SiC JFET Wafer: DC Parameter Variations for Extreme Temperature IC Design

    Science.gov (United States)

    Neudeck, Philip G.; Chen, Liangyu; Spry, David J.; Beheim, Glenn M.; Chang, Carl W.

    2014-01-01

    This work reports DC electrical characterization of a 76 mm diameter 4H-SiC JFET test wafer fabricated as part of NASA's on-going efforts to realize medium-scale ICs with prolonged and stable circuit operation at temperatures as high as 500 degC. In particular, these measurements provide quantitative parameter ranges for use in JFET IC design and simulation. Larger than expected parameter variations were observed both as a function of position across the wafer as well as a function of ambient testing temperature from 23 degC to 500 degC.

  17. Patterns of variation in reproductive parameters in Eurasian lynx (Lynx lynx).

    Science.gov (United States)

    Nilsen, Erlend B; Linnell, John D C; Odden, John; Samelius, Gustaf; Andrén, Henrik

    2012-07-01

    Detailed knowledge of the variation in demographic rates is central for our ability to understand the evolution of life history strategies and population dynamics, and to plan for the conservation of endangered species. We studied variation in reproductive output of 61 radio-collared Eurasian lynx females in four Scandinavian study sites spanning a total of 223 lynx-years. Specifically, we examined how the breeding proportion and litter size varied among study areas and age classes (2-year-old vs. >2-year-old females). In general, the breeding proportion varied between age classes and study sites, whereas we did not detect such variation in litter size. The lack of differences in litter sizes among age classes is at odds with most findings in large mammals, and we argue that this is because the level of prenatal investment is relatively low in felids compared to their substantial levels of postnatal care.

  18. Variations in environmental tritium doses due to meteorological data averaging and uncertainties in pathway model parameters

    Energy Technology Data Exchange (ETDEWEB)

    Kock, A.

    1996-05-01

    The objectives of this research are: (1) to calculate and compare off site doses from atmospheric tritium releases at the Savannah River Site using monthly versus 5 year meteorological data and annual source terms, including additional seasonal and site specific parameters not included in present annual assessments; and (2) to calculate the range of the above dose estimates based on distributions in model parameters given by uncertainty estimates found in the literature. Consideration will be given to the sensitivity of parameters given in former studies.

  19. Net thrust calculation sensitivity of an afterburning turbofan engine to variations in input parameters

    Science.gov (United States)

    Hughes, D. L.; Ray, R. J.; Walton, J. T.

    1985-01-01

    The calculated value of net thrust of an aircraft powered by a General Electric F404-GE-400 afterburning turbofan engine was evaluated for its sensitivity to various input parameters. The effects of a 1.0-percent change in each input parameter on the calculated value of net thrust with two calculation methods are compared. This paper presents the results of these comparisons and also gives the estimated accuracy of the overall net thrust calculation as determined from the influence coefficients and estimated parameter measurement accuracies.

  20. Accurate measurements of experimental parameters in supercritical fluid chromatography. I. Extent of variations of the mass and volumetric flow rates.

    Science.gov (United States)

    Tarafder, Abhijit; Guiochon, Georges

    2013-04-12

    Previous reports have highlighted the influence of the properties of the mobile phase flow rate on the column performance achieved in supercritical fluid chromatography (SFC). In SFC both the mass and the volumetric flow rates have unique influences on the chromatographic performance and the determination of their exact values is critical. It is well understood that the mass flow rate stays constant along an SFC system whereas the volumetric flow rate may vary considerably, but the extent of these variations and the role of the individual operating parameters in influencing these variations have not been clearly reported yet. The factors that control the mass and the volumetric flow rates in an SFC system are discussed and the possible extent of variations of these flow rates under different operating pressures and temperatures are demonstrate quantitatively. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Seasonal Variation in Physicochemical and Microbial Parameters in Treated River Water from Bangladesh

    National Research Council Canada - National Science Library

    Mahedy Hasan Chowdhury; Partha Saha; S M Estiar Haque; Md Fuadh-Al-Kabir

    2013-01-01

      This study examines the main Physico-chemical and microbial water quality parameters of drinking water supplied by Chandnighat Water Treatment Plant, which treat raw water from the river Buriganga...

  2. On-line estimation and compensation scheme for dead time and inverter nonlinearity independent of parameter variations in PMSM drive

    Science.gov (United States)

    Kim, Kyeong-Hwa

    2012-12-01

    A new on-line compensation scheme that can exactly estimate the dead time and inverter nonlinearity even under the parameter variations is proposed for a PWM inverter-fed permanent magnet synchronous motor drive. The proposed scheme is based on the fact that the sixth-order harmonic component in total disturbance estimated under the presence of various uncertainties is mainly caused by the dead time and inverter nonlinearity. The total disturbance due to the parameter variations as well as the dead time and inverter nonlinearity is estimated by the adaptive scheme. From this total disturbance, the sixth-order harmonic component is extracted through the harmonic analysis. The obtained sixth-order harmonic is processed by the PI controller to estimate the disturbance only caused by the dead time and inverter nonlinearity in the stationary reference frame. The effectiveness of the proposed scheme is verified through the comparative simulations and experiments using DSP TMS320F28335. Without requiring an additional hardware, the proposed scheme can effectively compensate the dead time and inverter nonlinearity even under the parameter variations.

  3. Latitudinal variations of aerosol optical parameters over South Africa based on MISR satellite data

    CSIR Research Space (South Africa)

    Tesfaye M

    2010-09-01

    Full Text Available The latitudunal variation of the relative weight size distribution and optical properties of aerosols over South Africa is presented here. The study uses 10-years of Multi-angle Imaging SpectroRadiometer (MISR) satellite data, collected over South...

  4. Influence of Population Variation of Physiological Parameters in Computational Models of Space Physiology

    Science.gov (United States)

    Myers, J. G.; Feola, A.; Werner, C.; Nelson, E. S.; Raykin, J.; Samuels, B.; Ethier, C. R.

    2016-01-01

    The earliest manifestations of Visual Impairment and Intracranial Pressure (VIIP) syndrome become evident after months of spaceflight and include a variety of ophthalmic changes, including posterior globe flattening and distension of the optic nerve sheath. Prevailing evidence links the occurrence of VIIP to the cephalic fluid shift induced by microgravity and the subsequent pressure changes around the optic nerve and eye. Deducing the etiology of VIIP is challenging due to the wide range of physiological parameters that may be influenced by spaceflight and are required to address a realistic spectrum of physiological responses. Here, we report on the application of an efficient approach to interrogating physiological parameter space through computational modeling. Specifically, we assess the influence of uncertainty in input parameters for two models of VIIP syndrome: a lumped-parameter model (LPM) of the cardiovascular and central nervous systems, and a finite-element model (FEM) of the posterior eye, optic nerve head (ONH) and optic nerve sheath. Methods: To investigate the parameter space in each model, we employed Latin hypercube sampling partial rank correlation coefficient (LHSPRCC) strategies. LHS techniques outperform Monte Carlo approaches by enforcing efficient sampling across the entire range of all parameters. The PRCC method estimates the sensitivity of model outputs to these parameters while adjusting for the linear effects of all other inputs. The LPM analysis addressed uncertainties in 42 physiological parameters, such as initial compartmental volume and nominal compartment percentage of total cardiac output in the supine state, while the FEM evaluated the effects on biomechanical strain from uncertainties in 23 material and pressure parameters for the ocular anatomy. Results and Conclusion: The LPM analysis identified several key factors including high sensitivity to the initial fluid distribution. The FEM study found that intraocular pressure and

  5. Signal intensities derived from different NMR probes and parameters contribute to variations in quantification of metabolites.

    Directory of Open Access Journals (Sweden)

    Paige Lacy

    Full Text Available We discovered that serious issues could arise that may complicate interpretation of metabolomic data when identical samples are analyzed at more than one NMR facility, or using slightly different NMR parameters on the same instrument. This is important because cross-center validation metabolomics studies are essential for the reliable application of metabolomics to clinical biomarker discovery. To test the reproducibility of quantified metabolite data at multiple sites, technical replicates of urine samples were assayed by 1D-(1H-NMR at the University of Alberta and the University of Michigan. Urine samples were obtained from healthy controls under a standard operating procedure for collection and processing. Subsequent analysis using standard statistical techniques revealed that quantitative data across sites can be achieved, but also that previously unrecognized NMR parameter differences can dramatically and widely perturb results. We present here a confirmed validation of NMR analysis at two sites, and report the range and magnitude that common NMR parameters involved in solvent suppression can have on quantitated metabolomics data. Specifically, saturation power levels greatly influenced peak height intensities in a frequency-dependent manner for a number of metabolites, which markedly impacted the quantification of metabolites. We also investigated other NMR parameters to determine their effects on further quantitative accuracy and precision. Collectively, these findings highlight the importance of and need for consistent use of NMR parameter settings within and across centers in order to generate reliable, reproducible quantified NMR metabolomics data.

  6. Biological and analytical variations of 16 parameters related to coagulation screening tests and the activity of coagulation factors.

    Science.gov (United States)

    Chen, Qian; Shou, Weiling; Wu, Wei; Guo, Ye; Zhang, Yujuan; Huang, Chunmei; Cui, Wei

    2015-04-01

    To accurately estimate longitudinal changes in individuals, it is important to take into consideration the biological variability of the measurement. The few studies available on the biological variations of coagulation parameters are mostly outdated. We confirmed the published results using modern, fully automated methods. Furthermore, we added data for additional coagulation parameters. At 8:00 am, 12:00 pm, and 4:00 pm on days 1, 3, and 5, venous blood was collected from 31 healthy volunteers. A total of 16 parameters related to coagulation screening tests as well as the activity of coagulation factors were analyzed; these included prothrombin time, fibrinogen (Fbg), activated partial thromboplastin time, thrombin time, international normalized ratio, prothrombin time activity, activated partial thromboplastin time ratio, fibrin(-ogen) degradation products, as well as the activity of factor II, factor V, factor VII, factor VIII, factor IX, and factor X. All intraindividual coefficients of variation (CVI) values for the parameters of the screening tests (except Fbg) were less than 5%. Conversely, the CVI values for the activity of coagulation factors were all greater than 5%. In addition, we calculated the reference change value to determine whether a significant difference exists between two test results from the same individual. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  7. Passive magnetic bearings for vehicular electromechanical batteries

    Energy Technology Data Exchange (ETDEWEB)

    Post, R

    1996-03-01

    This report describes the design of a passive magnetic bearing system to be used in electromechanical batteries (flywheel energy storage modules) suitable for vehicular use. One or two such EMB modules might, for example, be employed in a hybrid-electric automobile, providing efficient means for power peaking, i.e., for handling acceleration and regenerative braking power demands at high power levels. The bearing design described herein will be based on a ''dual-mode'' operating regime.

  8. Quartz-superconductor quantum electromechanical system

    OpenAIRE

    Woolley, M. J.; Emzir, M. F.; Milburn, G. J.; Jerger, M.; Goryachev, M.; Tobar, M. E.; Fedorov, A.

    2016-01-01

    We propose and analyse a quantum electromechanical system composed of a monolithic quartz bulk acoustic wave (BAW) oscillator coupled to a superconducting transmon qubit via an intermediate LC electrical circuit. Monolithic quartz oscillators offer unprecedentedly high effective masses and quality factors for the investigation of mechanical oscillators in the quantum regime. Ground-state cooling of such mechanical modes via resonant piezoelectric coupling to an LC circuit, which is itself sid...

  9. Employment of single-diode model to elucidate the variations in photovoltaic parameters under different electrical and thermal conditions.

    Science.gov (United States)

    Muhammad, Fahmi F; Yahya, Mohd Y; Hameed, Shilan S; Aziz, Fakhra; Sulaiman, Khaulah; Rasheed, Mariwan A; Ahmad, Zubair

    2017-01-01

    In this research work, numerical simulations are performed to correlate the photovoltaic parameters with various internal and external factors influencing the performance of solar cells. Single-diode modeling approach is utilized for this purpose and theoretical investigations are compared with the reported experimental evidences for organic and inorganic solar cells at various electrical and thermal conditions. Electrical parameters include parasitic resistances (Rs and Rp) and ideality factor (n), while thermal parameters can be defined by the cells temperature (T). A comprehensive analysis concerning broad spectral variations in the short circuit current (Isc), open circuit voltage (Voc), fill factor (FF) and efficiency (η) is presented and discussed. It was generally concluded that there exists a good agreement between the simulated results and experimental findings. Nevertheless, the controversial consequence of temperature impact on the performance of organic solar cells necessitates the development of a complementary model which is capable of well simulating the temperature impact on these devices performance.

  10. Learning optimal spatially-dependent regularization parameters in total variation image denoising

    Science.gov (United States)

    Van Chung, Cao; De los Reyes, J. C.; Schönlieb, C. B.

    2017-07-01

    We consider a bilevel optimization approach in function space for the choice of spatially dependent regularization parameters in TV image denoising models. First- and second-order optimality conditions for the bilevel problem are studied when the spatially-dependent parameter belongs to the Sobolev space {{H}1}≤ft(Ω \\right) . A combined Schwarz domain decomposition-semismooth Newton method is proposed for the solution of the full optimality system and local superlinear convergence of the semismooth Newton method is verified. Exhaustive numerical computations are finally carried out to show the suitability of the approach.

  11. Development of a Tunable Electromechanical Acoustic Liner for Engine Nacelles

    Science.gov (United States)

    Liu, Fei; Sheplak, Mark; Cattafesta, Louis N., III

    2007-01-01

    This report describes the development of a tunable electromechanical Helmholtz resonator (EMHR) for engine nacelles using smart materials technology. This effort addresses both near-term and long-term goals for tunable electromechanical acoustic liner technology for the Quiet Aircraft Technology (QAT) Program. Analytical models, i.e. lumped element model (LEM) and transfer matrix (TM) representation of the EMHR, have been developed to predict the acoustic behavior of the EMHR. The models have been implemented in a MATLAB program and used to compare with measurement results. Moreover, the prediction performance of models is further improved with the aid of parameter extraction of the piezoelectric backplate. The EMHR has been experimentally investigated using standard two-microphone method (TMM). The measurement results validated both the LEM and TM models of the EMHR. Good agreement between predicted and measured impedance is obtained. Short- and open circuit loads define the limits of the tuning range using resistive and capacitive loads. There is approximately a 9% tuning limit under these conditions for the non-optimized resonator configuration studied. Inductive shunt loads result in a 3 degree-of-freedom DOF) system and an enhanced tuning range of over 20% that is not restricted by the short- and open-circuit limits. Damping coefficient ' measurements for piezoelectric backplates in a vacuum chamber are also performed and indicate that the damping is dominated by the structural damping losses, such as compliant boundaries, and other intrinsic loss mechanisms. Based on models of the EMHR, a Pareto optimization design of the EMHR has been performed for the EMHR with non-inductive loads. The EMHR with non-inductive loads is a 2DOF system with two resonant fiequencies. The tuning ranges of the two resonant frequencies of the EMHR with non-inductive loads cannot be optimized simultaneously; a trade-off (i.e., a Pareto solution) must be reached. The Pareto solution

  12. Microstructural studies on variation of defect parameters in Zr–Sn ...

    Indian Academy of Sciences (India)

    Finally the microstructural parameters such as coherent domain size, microstrains within domains, faulting probability and dislocation density were evaluated from the analysis of X-ray powder diffraction data of Zr base Sn, Ti and Ti base Zr alloys by modified Rietveld powder structure refinement. This analysis confirms that ...

  13. Variation in semen parameters derived from computer-aided semen analysis, within donors and between donors

    NARCIS (Netherlands)

    Wijchman, JG; De Wolf, BTHM; Graaff, R; Arts, EGJM

    2001-01-01

    The development of computer-aided semen analysis (CASA) has made it possible to study sperm motility characteristics objectively and longitudinally. In this 2-year study of 8 sperm donors, we used CASA to measure 7 semen parameters (concentration, percentage of motile spermatozoa, curvilinear

  14. THE SPATIAL VARIATION OF MORPHOLOGICAL PARAMETERS OF VIRGIN AND TILED SOILS

    Directory of Open Access Journals (Sweden)

    A. Ursu

    2007-10-01

    Full Text Available Is established that the morphological parameters of soils change on small distance. Especially appreciably vary the depth of transitive horizons (B in brown and gray soils, as under a forest, and ploughed up. All on distance of two meters the general depth of soil (A + B and the depth of penetration of carbonates varies also.

  15. Spectroscopic diagnostics of HTSC parameter variations induced by CO2 lasers

    Science.gov (United States)

    Vasyuk, N. N.; Dovgii, Ya. O.; Kityk, I. V.; Lutsiv, R. V.; Malinich, S. Z.

    1992-11-01

    The effect of carbon dioxide laser radiation on yttrium barium copper oxide superconducting ceramics is examined. Results of reflection spectra measurements in the region of electron transitions and lattice vibration measurements show that the irradiation tends to make the high temperature superconducting ceramic parameters vary in the direction of semiconductor properties.

  16. DETERMINE THE RANGE OF VARIATION OF THE CONTROL SUBSYSTEM OUTPUT PARAMETERS

    Directory of Open Access Journals (Sweden)

    M. A. Bobrin

    2015-01-01

    Full Text Available For the evaluation of the tolerance of output parameters of the controls functional subsystem the hydraulic system under different operating conditions and phases of flight are given mathematical relationships and the results obtained in Mathcad are given in graphical form.

  17. Electromechanical performance of piezoelectric scanning mirrors for medical endoscopy.

    Science.gov (United States)

    Gilchrist, Kristin H; Dausch, David E; Grego, Sonia

    2012-05-01

    The electromechanical performance of piezoelectric scanning mirrors for endoscopy imaging is presented. The devices are supported by a single actuating cantilever to achieve a high fill factor, the ratio of mirror area to the combined mirror and actuator area. The largest fill factor devices (74%) achieved 10° mechanical scan range at +/-10V with a 300 μm long cantilever. The largest angular displacement of 30° mechanical scan range was obtained with a 500 μm long cantilever device with a 63% fill factor driven at 40 Vpp. A systematic investigation of device performance (displacement and speed) as a function of fabrication and operational parameters including the stress balance in the cantilever revealed unexpectedly large displacements with lack of inversion at the coercive field. An interpretation of the results is presented based on piezoelectric film domain orientation and clamping with supporting piezoelectric film characterization measurements.

  18. Modeling Electromechanical Overcurrent Relays Using Singular Value Decomposition

    Directory of Open Access Journals (Sweden)

    Feng-Jih Wu

    2012-01-01

    Full Text Available This paper presents a practical and effective novel approach to curve fit electromechanical (EM overcurrent (OC relay characteristics. Based on singular value decomposition (SVD, the curves are fitted with equation in state space under modal coordinates. The relationships between transfer function and Markov parameters are adopted in this research to represent the characteristic curves of EM OC relays. This study applies the proposed method to two EM OC relays: the GE IAC51 relay with moderately inverse-time characteristic and the ABB CO-8 relay with inverse-time characteristic. The maximum absolute values of errors of hundreds of sample points taken from four time dial settings (TDS for each relay between the actual characteristic curves and the corresponding values from the curve-fitting equations are within the range of 10 milliseconds. Finally, this study compares the SVD with the adaptive network and fuzzy inference system (ANFIS to demonstrate its accuracy and identification robustness.

  19. Micro Electromechanical Systems (MEMS Based Microfluidic Devices for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Nitin Afzulpurkar

    2011-06-01

    Full Text Available Micro Electromechanical Systems (MEMS based microfluidic devices have gained popularity in biomedicine field over the last few years. In this paper, a comprehensive overview of microfluidic devices such as micropumps and microneedles has been presented for biomedical applications. The aim of this paper is to present the major features and issues related to micropumps and microneedles, e.g., working principles, actuation methods, fabrication techniques, construction, performance parameters, failure analysis, testing, safety issues, applications, commercialization issues and future prospects. Based on the actuation mechanisms, the micropumps are classified into two main types, i.e., mechanical and non-mechanical micropumps. Microneedles can be categorized according to their structure, fabrication process, material, overall shape, tip shape, size, array density and application. The presented literature review on micropumps and microneedles will provide comprehensive information for researchers working on design and development of microfluidic devices for biomedical applications.

  20. Variations of atmospheric electric field and meteorological parameters in Kamchatka in 1997-2016

    Directory of Open Access Journals (Sweden)

    Smirnov Sergey

    2017-01-01

    Full Text Available Analysis of seasonal and annual variations of aero-electric field at a midlatitudinal observatory Paratunka in Kamchatka was carried out for 1997-2016. Stable seasonal intervals of the highest and the lowest values are observed. Changeability of the annual trend of aero-electric field in the near ground air layer at the observatory located in an active geodynamic region is shown. A large positive trend was changed by a smooth negative one. It is likely to be associated either with radon emanation intensity change in the observatory region or with volcanic activity change in Kamchatka.

  1. Variation of biometric parameters in corn cobs under the influence of nitrogen fertilization

    Science.gov (United States)

    Gigel, Prisecaru; Florin, Sala

    2017-07-01

    Biometric parameters as elements of productivity on corn cobs, along with plant density per unit area (ha) are essential in achieving production. The influence of differentiated fertilization with nitrogen was evaluated at the level of productivity elements on corn cobs, Andreea hybrid. Biometric parameters of the corn cobs (total length - L; usable length - l; uncoated length with corn kernels - lu; diameter at the base - Db, middle - Dm, and top of the corn cobs - Dt; corn cob weight - Cw, grain weight - Gw) were directly influenced by the doses of nitrogen. Regression analysis has facilitated the prediction of grain weight as the main element of productivity under different statistical certainty based on nitrogen doses (R2 = 0.962, pcorn cobs (R2 = 0.985, pcorn cobs (R2 = 0.996, pcorn cobs (R2 = 0.824, pcorn cobs (R2 = 0.807, pcorn kernels (R2 = 0.624, pcorn cobs (R2 = 0.384, p=0.015).

  2. Adaptive testing of Materials using Preisach Model Parameters Variations - Introductory Tests

    Directory of Open Access Journals (Sweden)

    Tomas Visnovec

    2004-01-01

    Full Text Available A new diagnostic method (MAT - Magnetic Adaptive Testing for non-destructive testing of ferromagnetic construction materials (i.e. iron based under mechanical stress is under development, [1]. The method is based on the investigation of the correlation between the mechanical load and the parameters of Preisach-like model describing magnetic properties of such materials as the differential permeability matrix. To get the set of model parameters needed, a number of minor hysteresis loops under defined exciting magnetic field strength waveform shape H(t, especially with constant field change rate dH(t/dt required (which implies the inducted voltage to be proportional to the differential permeability, is to be measured. The influence of initial magnetic state of the investigated material, algorithm of demagnetisation process, the slope of time dependence of exciting magnetic field on the signal-to-noise ratio and stability of the measured signal is discussed.

  3. Variation of UPFC Controllable Parameters during Power Swing and their Impacts on Distance Relay

    DEFF Research Database (Denmark)

    Khodaparast, Jalal; Khederzadeh, Mojtaba; Silva, Filipe Miguel Faria da

    2017-01-01

    Unified power flow controller (UPFC) has impact on the performance of distance relay during power swing. Generally, power system's parameters oscillate during power swing and since UPFC operation depends on some of these parameters (bus voltage, active and reactive power), the UPFC injects...... oscillated series voltage and draws oscillated shunt current. These oscillating series voltage and shunt current influence distance relays, as the impedance seen by a distance relay during power swing changes in UPFC-compensated lines. This study shows how and why series voltage and shunt current change...... during power swing. Moreover, the admittance swing characteristic is proposed in this study and effects of series and shunt branches of UPFC on the admittance seen by a distance relay during power swing have been examined....

  4. Variation of semen parameters in healthy medical students due to exam stress.

    Science.gov (United States)

    Lampiao, Fanuel

    2009-12-01

    This study was aimed at investigating semen parameters that vary most in samples of healthy donors undergoing stressful examination period. Samples were left to liquefy in an incubator at 37 degrees C, 5% CO2 for 30 minutes before volume was measured. Concentration and motility parameters were measured by means of computer assisted semen analysis (CASA) using Sperm Class Analyzer (Microptic S.L, Madrid, Spain). Sperm concentration was significantly decreased in samples donated close to the exam period as well as samples donated during the exam period when compared to samples donated at the beginning of the semester. Stress levels of donors might prove to be clinically relevant and important when designing experiment protocols.

  5. On Non-Linear Sensitivity of Marine Biological Models to Parameter Variations

    Science.gov (United States)

    2007-01-01

    total effect for the fall-bloom landmark also depends on the parameters for the nutrient distribution below the mixed layer as well as photosynthesis ...Technometrics 27, 151–163. Efron, B., Tibshirani, R.J., 1993. An Introduction to the Bootstrap. Monographs on Statistics and Applied Probability N 57...problem. Nonlinear Proc. Geophys. 1, 224–233. Jassby, A., Platt, T., 1976. Mathematical formulation of the relationship between photosynthesis and

  6. Four-order stiffness variation of laser-fabricated photopolymer biodegradable scaffolds by laser parameter modulation

    Energy Technology Data Exchange (ETDEWEB)

    Farkas, Balázs; Romano, Ilaria; Ceseracciu, Luca; Diaspro, Alberto [Department of Nanophysics, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova (Italy); Brandi, Fernando [Department of Nanophysics, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova (Italy); Istituto Nazionale di Ottica, Via Moruzzi 1, 56124 Pisa (Italy); Beke, Szabolcs, E-mail: szabolcs.beke@iit.it [Department of Nanophysics, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova (Italy)

    2015-10-01

    The effects of various fabrication parameters of our Mask Projection Excimer Laser StereoLithography (MPExSL) system were investigated. We demonstrate that laser parameters directly change the physical properties (stiffness, thermal degradation, and height/thickness) of the poly(propylene fumarate) (PFF) scaffold structures. The tested parameters were the number of pulses, fluence per pulse and laser repetition rate. We present a four-order tuning capability of MPExSL-fabricated structures' stiffness without altering the resin composition or using cumbersome post-treatment procedures. Thermogravimetric analysis and differential scanning calorimetry confirmed this tuning capability. Prototype-segmented scaffold designs are presented and analyzed to further expand the concept and exploit this in situ stiffness tuning capability of the scaffolds for tissue engineering and regenerative medicine applications. - Highlights: • Facile stiffness control of scaffolds is beneficial in tissue engineering. • Four-order tuning capability of structures' stiffness is presented. • Scaffold's stiffness can be tuned in four orders (4 MPa–4 GPa). • All scaffolds have been fabricated from the same polymer resin in a broad stiffness range.

  7. Active Electromechanical Suspension System for Planetary Rovers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Balcones Technologies, LLC proposes to adapt actively controlled suspension technology developed by The University of Texas at Austin Center for Electromechanics...

  8. Exploring natural variation of photosynthetic, primary metabolism and growth parameters in a large panel of Capsicum chinense accessions.

    Science.gov (United States)

    Rosado-Souza, Laise; Scossa, Federico; Chaves, Izabel S; Kleessen, Sabrina; Salvador, Luiz F D; Milagre, Jocimar C; Finger, Fernando; Bhering, Leonardo L; Sulpice, Ronan; Araújo, Wagner L; Nikoloski, Zoran; Fernie, Alisdair R; Nunes-Nesi, Adriano

    2015-09-01

    Collectively, the results presented improve upon the utility of an important genetic resource and attest to a complex genetic basis for differences in both leaf metabolism and fruit morphology between natural populations. Diversity of accessions within the same species provides an alternative method to identify physiological and metabolic traits that have large effects on growth regulation, biomass and fruit production. Here, we investigated physiological and metabolic traits as well as parameters related to plant growth and fruit production of 49 phenotypically diverse pepper accessions of Capsicum chinense grown ex situ under controlled conditions. Although single-trait analysis identified up to seven distinct groups of accessions, working with the whole data set by multivariate analyses allowed the separation of the 49 accessions in three clusters. Using all 23 measured parameters and data from the geographic origin for these accessions, positive correlations between the combined phenotypes and geographic origin were observed, supporting a robust pattern of isolation-by-distance. In addition, we found that fruit set was positively correlated with photosynthesis-related parameters, which, however, do not explain alone the differences in accession susceptibility to fruit abortion. Our results demonstrated that, although the accessions belong to the same species, they exhibit considerable natural intraspecific variation with respect to physiological and metabolic parameters, presenting diverse adaptation mechanisms and being a highly interesting source of information for plant breeders. This study also represents the first study combining photosynthetic, primary metabolism and growth parameters for Capsicum to date.

  9. Seasonal variation of gravity wave parameters using different filter methods with daylight lidar measurements at midlatitudes

    Science.gov (United States)

    Baumgarten, K.; Gerding, M.; Lübken, F.-J.

    2017-03-01

    The daylight-capable Rayleigh-Mie-Raman (RMR) lidar at the midlatitude station in Kühlungsborn (54°N, 12°E) is in operation since 2010. The RMR lidar system is used to investigate different fractions of atmospheric waves, like gravity waves (GW) and thermal tides (with diurnal, semidiurnal, and terdiurnal components) at day and night. About 6150 h of data have been acquired until 2015. The general challenge for GW observations is the separation of different wave contributions from the observed superposition of GW, tides, or even longer periodic waves. Unfiltered lidar data always include such a superposition. We applied a Butterworth filter to separate GW and tides by vertical wavelength with a cutoff wavelength of 15 km and by observed periods with a cutoff period of 8 h. GW activity and characteristics are derived in an altitude range between 30 and 70 km. The retrieved vertically filtered temperature deviations contain GW with small vertical wavelengths over a broad range of periods, while only a small range of periods is included in the temporally filtered temperature deviations. We observe an annual variation of the wave activity for unfiltered and vertically filtered data, which is caused from tides and inertia gravity waves. In contrast to that, filtering in time leads to a weak semiannual variation for gravity waves with periods of 4-8 h, especially in higher altitudes. During summer, these waves have the half of the total amount of the potential energy budget compared to the unfiltered data. This shows the importance of waves with periods smaller than 8 h.

  10. Towards noninvasive method for the detection of pathological tissue variations by mapping different blood parameters

    Science.gov (United States)

    Abdallah, Omar; Qananwah, Qasem; Abo Alam, Kawther; Bolz, Armin

    2010-04-01

    This paper describes the development of an early detection method for probing pathological tissue variations. The method could be used for classifying various tissue alteration namely tumors tissue or skin disorders. The used approach is based on light scattering and absorption spectroscopy. Spectral content of the scattered light provides diagnostic information about the tissue contents. The importance of this method is using a safe light that has less power than the used in the imaging methods that will enable the frequent examination of tissue, while the exiting modalities have drawbacks like ionization, high cost, time-consuming, and agents' usage. A modality for mapping the oxygen saturation distribution in tissues noninvasively is new in this area of research, since this study focuses on the oxygen molecule in the tissue which supposed to be homogenously distributed through the tissues. Cancers may cause greater vascularization and greater oxygen consumption than in normal tissue. Therefore, oxygen existence and homogeneity will be alternated depending on the tissue state. In the proposed system, the signal was extracted after illuminating the tissue by light emitting diodes (LED's) that emits light in two wavelengths, red (660 nm) and infrared (880 nm). The absorption in these wavelengths is mainly due to oxyhemoglobin (HbO2) and deoxyhemoglobin (Hb) while other blood and tissue contents nearly have low effect on the signal. The backscattered signal which is received by a photodiodes array (128 PDs) was measured and processed using LabVIEW. Photoplethysmogram (PPG) signals have been measured at different locations. These signals will be used to differentiate between the normal and the pathological tissues. Variations in hemoglobin concentration and blood perfusion will also be used as an important indication feature for this purpose.

  11. Dynamic composting optimization through C/N ratio variation as a startup parameter

    OpenAIRE

    AZIM, Khalid; OUYIHYA, Khalid; AMELLOUK, Aomar; PERISSOL, Claude; THAMI ALAMI, Imane; Soudi, Brahim

    2014-01-01

    Different organic wastes (waste of tomato leaves and stems, sheep manure, olive mill waste and melon waste) were mixed with different proportions for different C/N ratio to make better use of tomato waste as it constitutes the majority of horticultural waste in the Souss-Massa region (south-western of Morocco). The objective of this study was to evaluate the effect of C/N ratio on the physicochemical parameters during aerobic composting process (temperature, relative humidity, pH, EC...), and...

  12. Reproductive parameters of tropical lesser noddies respond to local variations in oceanographic conditions and weather

    Science.gov (United States)

    Monticelli, David; Ramos, Jaime A.; Catry, Teresa; Pedro, Patricia; Paiva, Vitor H.

    2014-02-01

    Most attempts to link seabirds and climate/oceanographic effects have concerned the Atlantic and Pacific Oceans with comparatively few studies in the tropical Indian Ocean. This paper examines the reproductive response of the lesser noddy Anous tenuirostris to temporal fluctuations in oceanographic and climatic conditions using 8 years of monitoring data from Aride Island (Seychelles), tropical Western Indian Ocean. We tested the hypothesis that breeding parameters (mean hatching date, mean egg size, hatching and fledging successes) and chick growth are influenced by local, seasonal oceanographic conditions as expressed by ocean primary productivity (surface chlorophyll-a concentrations; CC), sea surface temperature (SST) and wind speed. We also examined the relationship between lesser noddy breeding parameters and climate conditions recorded at the basin-wide scale of the Indian Ocean (Indian Ocean Dipole Mode Index, DMI). Our findings suggest that birds had a tendency to lay slightly larger eggs during breeding seasons (years) with higher CC during April-June (pre-laying, laying and incubation periods). Hatching date was positively related to SST in April-June, with the regression parameters suggesting that each 0.5 °C increase in SST meant a delay of approx.10 days in hatching date. A negative linear relationship was also apparent between hatching success and SST in June-August (hatching and chick-rearing periods), while the quadratic regression models detected a significant effect of wind speed in June-August on fledging success. Body mass increments of growing chicks averaged over 7-day periods were positively related with (2-week) lagged CC values and negatively related with (2-week) lagged SST values. No significant relationship between DMI and lesser noddy breeding parameters was found, but DMI indices were strongly correlated with local SST. Altogether, our results indicate that the reproduction of this top marine predator is dictated by fluctuations in

  13. Bed Material and Parameter Variation for a Pressurized Biomass Fluidized Bed Process

    Science.gov (United States)

    Puchner, Bernhard; Pfeifer, Christoph; Hofbauer, Hermann

    A pressurized gas at high temperatures with low impurities often is a basic requirement for applications for biomass gasification. Therefore, the Vienna University of Technology, in cooperation with the Austrian Bioenergy Centre, operates a pressurized gasification pilot plant in order to investigate thepressurized gasification process and estimate its potential. Within the scope of this paper this test facility as well as its operation behavioris described. Furthermore the parameters pressure, gasification temperature, lambda value and gasification agent have been investigated regarding to their influenceon the producer gas composition and arepresented and discussed in the following.

  14. Application of a PID controller based on fuzzy logic to reduce variations in the control parameters in PWR reactors

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcelos, Wagner Eustaquio de; Lira, Carlos Alberto Brayner de Oliveira; Brito, Thiago Souza Pereira de; Afonso, Antonio Claudio Marques, E-mail: wagner@unicap.br, E-mail: cabol@ufpe.br, E-mail: afonsofisica@gmail.com, E-mail: thiago.brito86@yahoo.com.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Centro de Tecnologia e Geociencias. Departamento de Energia Nuclear; Cruz Filho, Antonio Jose da; Marques, Jose Antonio, E-mail: antonio.jscf@gmail.com, E-mail: jamarkss@uol.com.br [Universidade Catolica de Pernambuco (CCT/PUC-PE), Recife, PE (Brazil). Centro de Ciencias e Tecnologia; Teixeira, Marcello Goulart, E-mail: marcellogt@dcc.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Instituto de Matematica. Dept. de Matematica

    2013-07-01

    Nuclear reactors are in nature nonlinear systems and their parameters vary with time as a function of power level. These characteristics must be considered if large power variations occur in power plant operational regimes, such as in load-following conditions. A PWR reactor has a component called pressurizer, whose function is to supply the necessary high pressure for its operation and to contain pressure variations in the primary cooling system. The use of control systems capable of reducing fast variations of the operation variables and to maintain the stability of this system is of fundamental importance. The best-known controllers used in industrial control processes are proportional-integral-derivative (PID) controllers due to their simple structure and robust performance in a wide range of operating conditions. However, designing a fuzzy controller is seen to be a much less difficult task. Once a Fuzzy Logic controller is designed for a particular set of parameters of the nonlinear element, it yields satisfactory performance for a range of these parameters. The objective of this work is to develop fuzzy proportional-integral-derivative (fuzzy-PID) control strategies to control the level of water in the reactor. In the study of the pressurizer, several computer codes are used to simulate its dynamic behavior. At the fuzzy-PID control strategy, the fuzzy logic controller is exploited to extend the finite sets of PID gains to the possible combinations of PID gains in stable region. Thus the fuzzy logic controller tunes the gain of PID controller to adapt the model with changes in the water level of reactor. The simulation results showed a favorable performance with the use to fuzzy-PID controllers. (author)

  15. ANALYSIS OF THE INTRA-CITY VARIATION OF URBAN HEAT ISLAND AND ITS RELATION TO LAND SURFACE/COVER PARAMETERS

    Directory of Open Access Journals (Sweden)

    D. Gerçek

    2016-06-01

    Full Text Available Along with urbanization, sealing of vegetated land and evaporation surfaces by impermeable materials, lead to changes in urban climate. This phenomenon is observed as temperatures several degrees higher in densely urbanized areas compared to the rural land at the urban fringe particularly at nights, so-called Urban Heat Island. Urban Heat Island (UHI effect is related with urban form, pattern and building materials so far as it is associated with meteorological conditions, air pollution, excess heat from cooling. UHI effect has negative influences on human health, as well as other environmental problems such as higher energy demand, air pollution, and water shortage. Urban Heat Island (UHI effect has long been studied by observations of air temperature from thermometers. However, with the advent and proliferation of remote sensing technology, synoptic coverage and better representations of spatial variation of surface temperature became possible. This has opened new avenues for the observation capabilities and research of UHIs. In this study, "UHI effect and its relation to factors that cause it" is explored for İzmit city which has been subject to excess urbanization and industrialization during the past decades. Spatial distribution and variation of UHI effect in İzmit is analysed using Landsat 8 and ASTER day & night images of 2015 summer. Surface temperature data derived from thermal bands of the images were analysed for UHI effect. Higher temperatures were classified into 4 grades of UHIs and mapped both for day and night. Inadequate urban form, pattern, density, high buildings and paved surfaces at the expanse of soil ground and vegetation cover are the main factors that cause microclimates giving rise to spatial variations in temperatures across cities. These factors quantified as land surface/cover parameters for the study include vegetation index (NDVI, imperviousness (NDISI, albedo, solar insolation, Sky View Factor (SVF, building

  16. Analysis of the Intra-City Variation of Urban Heat Island and its Relation to Land Surface/cover Parameters

    Science.gov (United States)

    Gerçek, D.; Güven, İ. T.; Oktay, İ. Ç.

    2016-06-01

    Along with urbanization, sealing of vegetated land and evaporation surfaces by impermeable materials, lead to changes in urban climate. This phenomenon is observed as temperatures several degrees higher in densely urbanized areas compared to the rural land at the urban fringe particularly at nights, so-called Urban Heat Island. Urban Heat Island (UHI) effect is related with urban form, pattern and building materials so far as it is associated with meteorological conditions, air pollution, excess heat from cooling. UHI effect has negative influences on human health, as well as other environmental problems such as higher energy demand, air pollution, and water shortage. Urban Heat Island (UHI) effect has long been studied by observations of air temperature from thermometers. However, with the advent and proliferation of remote sensing technology, synoptic coverage and better representations of spatial variation of surface temperature became possible. This has opened new avenues for the observation capabilities and research of UHIs. In this study, "UHI effect and its relation to factors that cause it" is explored for İzmit city which has been subject to excess urbanization and industrialization during the past decades. Spatial distribution and variation of UHI effect in İzmit is analysed using Landsat 8 and ASTER day & night images of 2015 summer. Surface temperature data derived from thermal bands of the images were analysed for UHI effect. Higher temperatures were classified into 4 grades of UHIs and mapped both for day and night. Inadequate urban form, pattern, density, high buildings and paved surfaces at the expanse of soil ground and vegetation cover are the main factors that cause microclimates giving rise to spatial variations in temperatures across cities. These factors quantified as land surface/cover parameters for the study include vegetation index (NDVI), imperviousness (NDISI), albedo, solar insolation, Sky View Factor (SVF), building envelope

  17. Effect of parameter variations on the hemodynamic response under rotary blood pump assistance.

    Science.gov (United States)

    Lim, Einly; Dokos, Socrates; Salamonsen, Robert F; Rosenfeldt, Franklin L; Ayre, Peter J; Lovell, Nigel H

    2012-05-01

    Numerical models, able to simulate the response of the human cardiovascular system (CVS) in the presence of an implantable rotary blood pump (IRBP), have been widely used as a predictive tool to investigate the interaction between the CVS and the IRBP under various operating conditions. The present study investigates the effect of alterations in the model parameter values, that is, cardiac contractility, systemic vascular resistance, and total blood volume on the efficiency of rotary pump assistance, using an optimized dynamic heart-pump interaction model previously developed in our laboratory based on animal experimental measurements obtained from five canines. The effect of mean pump speed and the circulatory perturbations on left and right ventricular pressure volume loops, mean aortic pressure, mean cardiac output, pump assistance ratio, and pump flow pulsatility from both the greyhound experiments and model simulations are demonstrated. Furthermore, the applicability of some of the previously proposed control parameters, that is, pulsatility index (PI), gradient of PI with respect to pump speed, pump differential pressure, and aortic pressure are discussed based on our observations from experimental and simulation results. It was found that previously proposed control strategies were not able to perform well under highly varying circulatory conditions. Among these, control algorithms which rely on the left ventricular filling pressure appear to be the most robust as they emulate the Frank-Starling mechanism of the heart. © 2012, Copyright the Authors. Artificial Organs © 2012, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  18. Sensitivity of the model error parameter specification in weak-constraint four-dimensional variational data assimilation

    Science.gov (United States)

    Shaw, Jeremy A.; Daescu, Dacian N.

    2017-08-01

    This article presents the mathematical framework to evaluate the sensitivity of a forecast error aspect to the input parameters of a weak-constraint four-dimensional variational data assimilation system (w4D-Var DAS), extending the established theory from strong-constraint 4D-Var. Emphasis is placed on the derivation of the equations for evaluating the forecast sensitivity to parameters in the DAS representation of the model error statistics, including bias, standard deviation, and correlation structure. A novel adjoint-based procedure for adaptive tuning of the specified model error covariance matrix is introduced. Results from numerical convergence tests establish the validity of the model error sensitivity equations. Preliminary experiments providing a proof-of-concept are performed using the Lorenz multi-scale model to illustrate the theoretical concepts and potential benefits for practical applications.

  19. Analysis of influence on back-EMF based sensorless control of PMSM due to parameter variations and measurement errors

    DEFF Research Database (Denmark)

    Wang, Z.; Lu, K.; Ye, Y.

    2011-01-01

    and flux saturation, current and voltage errors due to measurement uncertainties, and signal delay caused by hardwares. This paper reveals some inherent principles for the performance of the back-EMF based sensorless algorithm embedded in a surface mounted PMSM system adapting vector control strategy......To achieve better performance of sensorless control of PMSM, a precise and stable estimation of rotor position and speed is required. Several parameter uncertainties and variable measurement errors may lead to estimation error, such as resistance and inductance variations due to temperature......, gives mathematical analysis and experimental results to support the principles, and quantify the effects of each. It may be a guidance for designers to minify the estimation error and make proper on-line parameter estimations....

  20. Variative Modeling of the Parameters of Delay throughout all Parts of the Chain of Logistics System of Enterprise

    Directory of Open Access Journals (Sweden)

    Sherstennikov Yuriy V.

    2017-04-01

    Full Text Available Enterprise’s ability to meet the needs of consumer is determined by the efficient work of all parts of the chain of enterprise’s logistics system: speed of processing orders, production capacity of enterprise, speed of product shipments, transportation to the end customer. The article is aimed at developing a general scheme of modeling the parameters of delay throughout all parts of the chain of logistics system. To do this, machinery of mass service theory was used. The work of small private enterprise «Еkokomplekt» was analyzed. A method for variative modeling the harmonization of work rate of the specific part of the chain with the common needs of the production has been developed. The mathematical programs for numerical characterization of the parameters of delay have been compiled using the mass service theory, positive economic results related to intensifying the rates of service of requirements to the activities of small enterprise have been obtained.

  1. Relationship between human physiological parameters and geomagnetic variations of solar origin

    Science.gov (United States)

    Dimitrova, S.

    Results presented concern influence of increased geomagnetic activity on some human physiological parameters. The blood pressure and heart rate of 86 volunteers were measured on working days in autumn 2001 (01/10 09/11) and in spring 2002 (08/04 28/05). These periods were chosen because of maximal expected geomagnetic activity. Altogether 2799 recordings were obtained and analysed. Questionnaire information about subjective psycho-physiological complaints was also gathered. MANOVA was employed to check the significance of the influence of three factors on the physiological parameters under consideration. The factors were the following: (1) planetary geomagnetic activity level estimated by Ap-index and divided into five levels; (2) gender males and females; (3) blood pressure degree persons in the group examined were divided into hypotensive, normotensive and hypertensive. Post hoc analysis was performed to elicit the significance of differences in the factors’ levels. The average arterial blood pressure of the group was found to increase significantly with the increase of geomagnetic activity level. The average increment of systolic and diastolic blood pressure of the group examined reached 9%. This effect was present irrespectively of gender. Results obtained suppose that hypertensive persons have the highest sensitivity and the hypotensive persons have the lowest sensitivity of the arterial blood pressure to increase of geomagnetic activity. The results did not show significant changes in the heart rate. The percentage of the persons who reported subjective psycho-physiological complaints was also found to increase significantly with the geomagnetic activity increase and the highest sensitivity was revealed for the hypertensive females.

  2. Variations in ionospheric parameters during periods of minimum and maximum solar activity

    Science.gov (United States)

    Taran, V. I.

    1996-12-01

    Ionospheric investigations in Ukraine are being carried out with uniquely developed incoherent scatter radars. Data on the variations in the electron density and the electron and ion temperatures during periods of low (1994) and high (1989 - 1990) solar activity are presented. The F-layer peak height ranges from 450 at night to 240 km in the daytime; the electron density maximum varies approximately from 0741-3335/38/12A/025/img1 over a cycle of solar activity throughout the winter period. The electron temperature has a maximum afternoon value as the solar activity is high in summer. In the periods of magnetic disturbances, a drop in 0741-3335/38/12A/025/img2 is most frequently observed. In winter, the influence of the sunrise and sunset at the magnetic conjugate point is also observed. An increase in electron temperature, a drop in electron density, and the displacement of the heated region along the magnetic field lines are clearly seen in the ionosphere irradiated by high-power, HF radiation. Longitudinal effects in the ionospheric behaviour were observed in simultaneous measurements in Kharkiv and Millstone Hill (USA).

  3. Spatial variation of physicochemical and bacteriological parameters elucidation with GIS in Rangat Bay, Middle Andaman, India

    Science.gov (United States)

    Dheenan, P. S.; Jha, Dilip Kumar; Vinithkumar, N. V.; Ponmalar, A. Angelin; Venkateshwaran, P.; Kirubagaran, R.

    2014-01-01

    The purpose of this study was to determine the concentration, distribution of bacteria and physicochemical property of surface seawater in Rangat Bay, Middle Andaman, Andaman Islands (India). The bay experiences tidal variations. Perhaps physicochemical properties of seawater in Rangat Bay were found not to vary significantly. The concentration of faecal streptococci was high (2.2 × 103 CFU/100 mL) at creek and harbour area, whereas total coliforms were high (7.0 × 102 CFU/100 mL) at mangrove area. Similarly, total heterotrophic bacterial concentration was high (5.92 × 104 CFU/100 mL) in mangrove and harbour area. The Vibrio cholerae and Vibrio parahaemolyticus concentration was high (4.2 × 104 CFU/100 mL and 9 × 103 CFU/100 mL) at open sea. Cluster analysis showed grouping of stations in different tidal periods. The spatial maps clearly depicted the bacterial concentration pattern in the bay. The combined approach of multivariate analysis and spatial mapping techniques was proved to be useful in the current study.

  4. Electromechanical stress analysis of transversely isotropic solenoids

    Energy Technology Data Exchange (ETDEWEB)

    Gray, W.H.; Ballou, J.K.

    1977-03-01

    The mechanical behavior of superconducting magnets deviates from isotropy due to their construction techniques, which involve layering superconductor, insulation, and sometimes structural reinforcement within the windings. Previous mechanical analyses considered the windings of a magnet to behave isotropically. This paper describes an analytical solution for the deflection, stress, and strain of axisymmetric, electromechanically loaded, and rotationally transversely isotropic solenoids. The results indicate that for magnets with a large radial build compared to inner radius, transverse isotropy has a dramatic effect upon the mechanical response to load; for magnets with a small radial build compared to inner radius, transverse isotropy has a negligible effect.

  5. Nano electro-mechanical optoelectronic tunable VCSEL.

    Science.gov (United States)

    Huang, Michael C Y; Zhou, Ye; Chang-Hasnain, Connie J

    2007-02-05

    We report a novel electrostatic actuated nano-electromechanical optoelectronic (NEMO) tunable vertical-cavity surface-emitting laser (VCSEL) centered at 850 nm. By integrating a movable, single-layer (230 nm), high-index-contrast subwavelength grating (HCG) as the VCSEL top mirror, single mode emission (SMSR >40 dB) and continuous wavelength tuning (~2.5 nm) was obtained at room temperature under CW operation. The small footprint of HCG enables the scaling down of each of the cantilever dimensions by a factor of 10, leading to 1000 times reduction in mass, which potentially increases the mechanical resonant frequency and tuning speed.

  6. Circuit For Control Of Electromechanical Prosthetic Hand

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1995-01-01

    Proposed circuit for control of electromechanical prosthetic hand derives electrical control signals from shoulder movements. Updated, electronic version of prosthesis, that includes two hooklike fingers actuated via cables from shoulder harness. Circuit built around favored shoulder harness, provides more dexterous movement, without incurring complexity of computer-controlled "bionic" or hydraulically actuated devices. Additional harness and potentiometer connected to similar control circuit mounted on other shoulder. Used to control stepping motor rotating hand about prosthetic wrist to one of number of angles consistent with number of digital outputs. Finger-control signals developed by circuit connected to first shoulder harness transmitted to prosthetic hand via sliprings at prosthetic wrist joint.

  7. Seasonal changes of buffalo colostrum: physicochemical parameters, fatty acids and cholesterol variation.

    Science.gov (United States)

    Coroian, Aurelia; Erler, Silvio; Matea, Cristian T; Mireșan, Vioara; Răducu, Camelia; Bele, Constantin; Coroian, Cristian O

    2013-02-26

    Colostrum has many beneficial effects on newborns due to its main compounds (proteins, fats, lactose, essential fatty acids, amino acids) as well as protective antibodies that confer to the body. The buffaloes are the second important species for milk production in the world after cows. The importance of the species is also conferred by a longer longevity, high dry content of milk and a strong organic resistance when compared with cows. The purpose of this study was to investigate the changes of buffalo colostrum compounds such as fatty acids, cholesterol and physicochemical parameters during the first seven days postpartum and under the impact of the season, summer on pasture and winter on dry diet (hay based). Fat from colostrum differs depending on the postpartum day showing mean values of 11.31-7.56% (summer season) and 11.22-7.51% (winter season). These values gradually decreased starting with first day postpartum until day seven. Dry substance and protein presented a similar evolution to fat reaching the lowest values at the end of the colostral period. Lactose, ash and pH showed a gradually increase reaching the maximum on day seven postpartum. The highest titres of fatty acids from colostrum are: butyric acid (C4:0), myristic acid (C14:0), palmitic acid (C16:0), oleic acid (C18:1) and the lowest values showed up in myristoleic acid (C14:1), cis-10-pentadecanoic acid (C15:1), pentadecylic acid (C15:0) and margaric acid (C17:0) for both seasons. Higher concentrations have been recorded for the summer season in general. Cholesterol concentration decreased from 12.93 and 12.68 mg/100 mL (summer and winter season) to 9.02 and 7.88 mg/100 mL in the end of the colostral period. Physicochemical compounds of buffalo colostrum were influenced by season and postpartum day of milking. Excepting lactose all other parameters gradually decreased during colostral period. Fatty acids and cholesterol showed the same evolution, presenting higher values for the summer season

  8. Variation of thermal parameters in two different color morphs of a diurnal poison toad, Melanophryniscus rubriventris (Anura: Bufonidae).

    Science.gov (United States)

    Sanabria, Eduardo A; Vaira, Marcos; Quiroga, Lorena B; Akmentins, Mauricio S; Pereyra, Laura C

    2014-04-01

    We study the variation in thermal parameters in two contrasting populations Yungas Redbelly Toads (Melanophryniscus rubriventris) with different discrete color phenotypes comparing field body temperatures, critical thermal maximum and heating rates. We found significant differences in field body temperatures of the different morphs. Temperatures were higher in toads with a high extent of dorsal melanization. No variation was registered in operative temperatures between the study locations at the moment of capture and processing. Critical thermal maximum of toads was positively related with the extent of dorsal melanization. Furthermore, we founded significant differences in heating rates between morphs, where individuals with a high extent of dorsal melanization showed greater heating rates than toads with lower dorsal melanization. The color pattern-thermal parameter relationship observed may influence the activity patterns and body size of individuals. Body temperature is a modulator of physiological and behavioral functions in amphibians, influencing daily and seasonal activity, locomotor performance, digestion rate and growth rate. It is possible that some growth constraints may arise due to the relationship of color pattern-metabolism allowing different morphs to attain similar sizes at different locations instead of body-size clines. Copyright © 2014. Published by Elsevier Ltd.

  9. The Social Network of Tracer Variations and O(100) Uncertain Photochemical Parameters in the Community Atmosphere Model

    Science.gov (United States)

    Lucas, D. D.; Labute, M.; Chowdhary, K.; Debusschere, B.; Cameron-Smith, P. J.

    2014-12-01

    Simulating the atmospheric cycles of ozone, methane, and other radiatively important trace gases in global climate models is computationally demanding and requires the use of 100's of photochemical parameters with uncertain values. Quantitative analysis of the effects of these uncertainties on tracer distributions, radiative forcing, and other model responses is hindered by the "curse of dimensionality." We describe efforts to overcome this curse using ensemble simulations and advanced statistical methods. Uncertainties from 95 photochemical parameters in the trop-MOZART scheme were sampled using a Monte Carlo method and propagated through 10,000 simulations of the single column version of the Community Atmosphere Model (CAM). The variance of the ensemble was represented as a network with nodes and edges, and the topology and connections in the network were analyzed using lasso regression, Bayesian compressive sensing, and centrality measures from the field of social network theory. Despite the limited sample size for this high dimensional problem, our methods determined the key sources of variation and co-variation in the ensemble and identified important clusters in the network topology. Our results can be used to better understand the flow of photochemical uncertainty in simulations using CAM and other climate models. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and supported by the DOE Office of Science through the Scientific Discovery Through Advanced Computing (SciDAC).

  10. A novel oscillation control for MEMS vibratory gyroscopes using a modified electromechanical amplitude modulation technique

    Science.gov (United States)

    Ma, Wei; Lin, Yiyu; Liu, Siqi; Zheng, Xudong; Jin, Zhonghe

    2017-02-01

    This paper reports a novel oscillation control algorithm for MEMS vibratory gyroscopes using a modified electromechanical amplitude modulation (MEAM) technique, which enhances the robustness against the frequency variation of the driving mode, compared to the conventional EAM (CEAM) scheme. In this approach, the carrier voltage exerted on the proof mass is frequency-modulated by the drive resonant frequency. Accordingly, the pick-up signal from the interface circuit involves a constant-frequency component that contains the amplitude and phase information of the vibration displacement. In other words, this informational detection signal is independent of the mechanical resonant frequency, which varies due to different batches, imprecise micro-fabrication and changing environmental temperature. In this paper, the automatic gain control loop together with the phase-locked loop are simultaneously analyzed using the averaging method and Routh-Hurwitz criterion, deriving the stability condition and the parameter optimization rules of the transient response. Then, a simulation model based on the real system is set up to evaluate the control algorithm. Further, the proposed MEAM method is tested using a field-programmable-gate-array based digital platform on a capacitive vibratory gyroscope. By optimizing the control parameters, the transient response of the drive amplitude reveals a settling time of 45.2 ms without overshoot, according well with the theoretical prediction and simulation results. The first measurement results show that the amplitude variance of the drive displacement is 12 ppm in an hour while the phase standard deviation is as low as 0.0004°. The mode-split gyroscope operating under atmospheric pressure demonstrates an outstanding performance. By virtue of the proposed MEAM method, the bias instability and angle random walk are measured to be 0.9° h-1 (improved by 2.4 times compared to the CEAM method) and 0.068° (√h)-1 (improved by 1.4 times

  11. Analytic Approximations to Nonlinear Boundary Value Problems Modeling Beam-Type Nano-Electromechanical Systems

    Science.gov (United States)

    Zou, Li; Liang, Songxin; Li, Yawei; Jeffrey, David J.

    2017-03-01

    Nonlinear boundary value problems arise frequently in physical and mechanical sciences. An effective analytic approach with two parameters is first proposed for solving nonlinear boundary value problems. It is demonstrated that solutions given by the two-parameter method are more accurate than solutions given by the Adomian decomposition method (ADM). It is further demonstrated that solutions given by the ADM can also be recovered from the solutions given by the two-parameter method. The effectiveness of this method is demonstrated by solving some nonlinear boundary value problems modeling beam-type nano-electromechanical systems.

  12. Analytic approximations to nonlinear boundary value problems modeling beam-type nano-electromechanical systems

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Li [Dalian Univ. of Technology, Dalian City (China). State Key Lab. of Structural Analysis for Industrial Equipment; Liang, Songxin; Li, Yawei [Dalian Univ. of Technology, Dalian City (China). School of Mathematical Sciences; Jeffrey, David J. [Univ. of Western Ontario, London (Canada). Dept. of Applied Mathematics

    2017-06-01

    Nonlinear boundary value problems arise frequently in physical and mechanical sciences. An effective analytic approach with two parameters is first proposed for solving nonlinear boundary value problems. It is demonstrated that solutions given by the two-parameter method are more accurate than solutions given by the Adomian decomposition method (ADM). It is further demonstrated that solutions given by the ADM can also be recovered from the solutions given by the two-parameter method. The effectiveness of this method is demonstrated by solving some nonlinear boundary value problems modeling beam-type nano-electromechanical systems.

  13. Evaluation of hydration status by urine, body mass variation and plasma parameters during an official half-marathon.

    Science.gov (United States)

    Pereira, Emerson R; de Andrade, Marcelo T; Mendes, Thiago T; Ramos, Guilherme P; Maia-Lima, André; Melo, Eliney S; Carvalho, Moisés V; Wilke, Carolina F; Prado, Luciano S; Silami-Garcia, Emerson

    2017-11-01

    The aim of this study was to verify the agreement of urine, body mass variations and plasma parameters to determine the hydration status of 14 male runners (29±4 years and 54.3±5.5 mLO2/kg/min) in an official 21.1 km road race. The mean dry-bulb temperature and air relative humidity during the road race were 25.1±2.1 °C and 54.7±2.2%, respectively. The volume of water ingested by the runners was monitored using marked volumetric plastic bottles provided at the hydration stations located at 0, 2.5, 5.0, 7.5, 10.5, 14.0, 16.0 and 18.5 km from the starting line. Hydration status was assessed using urine specific gravity (USG), urine osmolality (UOSM) and plasma osmolality (POSM). Furthermore, body mass variation (∆BM) was assessed by comparing body mass (BM) immediately prior and after the race. Total sweat was estimated by ∆BM, added water volume ingested and deducted blood volume collected. The sweat rate was calculated through total sweat and total exercise time. The mean water intake was 0.82±0.40 L, and the mean sweat rate and total sweating were 1440.11±182.13 mL/h and 2.67±0.23 L. After the race, the BM reduced by 1.7±0.4 kg. The ∆BM was -2.41±0.47%, and the plasma volume variation was -9.79±4.6% between pre- and post-running measurements. Despite the POSM increased post-race compared to pre-race, the UOSM and USG did not change. No significant correlations were found between POSM variation with UOSM variation (r=-0.08; P=0.71), USG variation (r=-0.11; P=0.78) or ∆BM (r=0.09; P=0.77). In conclusion, this study shows that both ∆BM and ∆POSM indicated a hypohydration state after exercise even though the ∆BM did not correlate significantly with ∆POSM. These results demonstrate that ∆BM is a practical method and can be sufficiently sensitive to evaluate the hydration state, but it should be utilized with caution.

  14. Composition and structure variation for magnetron sputtered tantalum oxynitride thin films, as function of deposition parameters

    Energy Technology Data Exchange (ETDEWEB)

    Cristea, D.; Pătru, M.; Crisan, A.; Munteanu, D. [Department of Materials Science, Transilvania University, 500036 Brasov (Romania); Crăciun, D. [Laser Department, National Institute for Laser, Plasma, and Radiation Physics, Magurele (Romania); Barradas, N.P. [Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10 ao km 139,7, 2695-066 Bobadela LRS (Portugal); Alves, E. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10 ao km 139,7, 2695-066 Bobadela LRS (Portugal); Apreutesei, M. [Université de Lyon, Institut des Nanotechnologies de Lyon INL-UMR 5270, CNRS, Ecole Centrale de Lyon, Ecully F-69134 (France); MATEIS Laboratory-INSA de Lyon, Bât. B. Pascal, 7 Avenue Jean Capelle, 69621 Villeurbanne Cedex (France); Moura, C. [Center of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Cunha, L., E-mail: lcunha@fisica.uminho.pt [Center of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal)

    2015-12-15

    Highlights: • Structural evolution from β-Ta, to fcc-Ta(O,N), to amorphous Ta{sub 2}O{sub 5} with increasing P(N{sub 2} + O{sub 2}). • The substrate bias influences the N content, but does not influence the O content of the films. • The structural features of the films appear at lower P(N{sub 2} + O{sub 2}) when produced with grounded substrate. - Abstract: Tantalum oxynitride thin films were produced by magnetron sputtering. The films were deposited using a pure Ta target and a working atmosphere with a constant N{sub 2}/O{sub 2} ratio. The choice of this constant ratio limits the study concerning the influence of each reactive gas, but allows a deeper understanding of the aspects related to the affinity of Ta to the non-metallic elements and it is economically advantageous. This work begins by analysing the data obtained directly from the film deposition stage, followed by the analysis of the morphology, composition and structure. For a better understanding regarding the influence of the deposition parameters, the analyses are presented by using the following criterion: the films were divided into two sets, one of them produced with grounded substrate holder and the other with a polarization of −50 V. Each one of these sets was produced with different partial pressure of the reactive gases P(N{sub 2} + O{sub 2}). All the films exhibited a O/N ratio higher than the N/O ratio in the deposition chamber atmosphere. In the case of the films produced with grounded substrate holder, a strong increase of the O content is observed, associated to the strong decrease of the N content, when P(N{sub 2} + O{sub 2}) is higher than 0.13 Pa. The higher Ta affinity for O strongly influences the structural evolution of the films. Grazing incidence X-ray diffraction showed that the lower partial pressure films were crystalline, while X-ray reflectivity studies found out that the density of the films depended on the deposition conditions: the higher the gas pressure, the

  15. Dayside ionosphere of Titan: Impact on calculated plasma densities due to variations in the model parameters

    Science.gov (United States)

    Mukundan, Vrinda; Bhardwaj, Anil

    2018-01-01

    A one dimensional photochemical model for the dayside ionosphere of Titan has been developed for calculating the density profiles of ions and electrons under steady state photochemical equilibrium condition. We concentrated on the T40 flyby of Cassini orbiter and used the in-situ measurements from instruments onboard Cassini as input to the model. An energy deposition model is employed for calculating the attenuated photon flux and photoelectron flux at different altitudes in Titan's ionosphere. We used the Analytical Yield Spectrum approach for calculating the photoelectron fluxes. Volume production rates of major primary ions, like, N2+, N+ , CH4+, CH3+, etc due to photon and photoelectron impact are calculated and used as input to the model. The modeled profiles are compared with the Cassini Ion Neutral Mass Spectrometer (INMS) and Langmuir Probe (LP) measurements. The calculated electron density is higher than the observation by a factor of 2 to 3 around the peak. We studied the impact of different model parameters, viz. photoelectron flux, ion production rates, electron temperature, dissociative recombination rate coefficients, neutral densities of minor species, and solar flux on the calculated electron density to understand the possible reasons for this discrepancy. Recent studies have shown that there is an overestimation in the modeled photoelectron flux and N2+ ion production rates which may contribute towards this disagreement. But decreasing the photoelectron flux (by a factor of 3) and N2+ ion production rate (by a factor of 2) decreases the electron density only by 10 to 20%. Reduction in the measured electron temperature by a factor of 5 provides a good agreement between the modeled and observed electron density. The change in HCN and NH3 densities affects the calculated densities of the major ions (HCNH+ , C2H5+, and CH5+); however the overall impact on electron density is not appreciable ( < 20%). Even though increasing the dissociative

  16. PARETO OPTIMAL SOLUTION OF MULTIOBJECTIVE SYNTHESIS OF ROBUST CONTROLLERS OF MULTIMASS ELECTROMECHANICAL SYSTEMS BASED ON MULTISWARM STOCHASTIC MULTIAGENT OPTIMIZATION

    Directory of Open Access Journals (Sweden)

    T.B. Nikitina

    2017-04-01

    Full Text Available Purpose. Developed the method for solving the problem of multiobjective synthesis of robust control by multimass electromechanical systems based on the construction of the Pareto optimal solutions using multiswarm stochastic multi-agent optimization of particles swarm, which reduces the time of determining the parameters of robust controls multimass electromechanical systems and satisfy a variety of requirements that apply to the work of such systems in different modes. Methodology. Multiobjective synthesis of robust control of multimass electromechanical systems is reduced to the solution of solving the problem of multiobjective optimization. To correct the above problem solving multiobjective optimization in addition to the vector optimization criteria and constraints must also be aware of the binary preference relations of local solutions against each other. The basis for such a formal approach is to build areas of Pareto-optimal solutions. This approach can significantly narrow down the range of possible solutions of the problem of optimal initial multiobjective optimization and, consequently, reduce the complexity of the person making the decision on the selection of a single version of the optimal solution. Results. The results of the synthesis of multi-criteria electromechanical servo system and a comparison of dynamic characteristics, and it is shown that the use of synthesized robust controllers reduced the error guidance working mechanism and reduced the system sensitivity to changes in the control parameters of the object compared to the existing system with standard controls. Originality. For the first time, based on the construction of the Pareto optimal solutions using a multiswarm stochastic multi-agent optimization particle algorithms improved method for solving formulated multiobjective multiextremal nonlinear programming problem with constraints, to which the problem of multiobjective synthesis of robust controls by multimass

  17. Temporal variations in parameters reflecting terminal-electron-accepting processes in an aquifer contaminated with waste fuel and chlorinated solvents

    Science.gov (United States)

    McGuire, Jennifer T.; Smith, Erik W.; Long, David T.; Hyndman, David W.; Haack, Sheridan K.; Klug, Michael J.; Velbel, Michael A.

    2000-01-01

    A fundamental issue in aquifer biogeochemistry is the means by which solute transport, geochemical processes, and microbiological activity combine to produce spatial and temporal variations in redox zonation. In this paper, we describe the temporal variability of TEAP conditions in shallow groundwater contaminated with both waste fuel and chlorinated solvents. TEAP parameters (including methane, dissolved iron, and dissolved hydrogen) were measured to characterize the contaminant plume over a 3-year period. We observed that concentrations of TEAP parameters changed on different time scales and appear to be related, in part, to recharge events. Changes in all TEAP parameters were observed on short time scales (months), and over a longer 3-year period. The results indicate that (1) interpretations of TEAP conditions in aquifers contaminated with a variety of organic chemicals, such as those with petroleum hydrocarbons and chlorinated solvents, must consider additional hydrogen-consuming reactions (e.g., dehalogenation); (2) interpretations must consider the roles of both in situ (at the sampling point) biogeochemical and solute transport processes; and (3) determinations of microbial communities are often necessary to confirm the interpretations made from geochemical and hydrogeological measurements on these processes.

  18. Modelling of shear lag effect for piezo-elstodynamic structure for electro-mechanical imedance technique

    Science.gov (United States)

    Moharana, Sumedha; Bhalla, Suresh

    2015-03-01

    The impedance based structural health monitoring (SHM) techniques have utilized the electro-mechanical coupling property of piezoelectric materials (piezo-impedance transducers), due to their self-sensing nature (ability to act both as actuators and sensors), and its diminutive in shape and size, cost effectiveness and ease of installation. The adhesive bond acts as an elastic medium which facilitates the transfer of stresses and strains developed due to piezo displacement and also couples the impedance of PZT patch with that of the host structure. The sensitivity of the electro-mechanical impedance (EMI) technique can be enhanced by understanding shear mechanism phenomena of the adhesive layer. This paper reviews the existing shear lag models and discuss the recent advances in impedance based coupled piezo-structural model duly considering the shear lag effect with all responsible piezo-mechanical parameters.

  19. Evaluation of atrial electromechanical delay and diastolic functions in patients with hyperthyroidism.

    Science.gov (United States)

    Sokmen, Abdullah; Acar, Gurkan; Sokmen, Gulizar; Akcay, Ahmet; Akkoyun, Murat; Koroglu, Sedat; Nacar, Alper Bugra; Ozkaya, Mesut

    2013-11-01

    Hyperthyroidism is a well-known cause of atrial fibrillation (AF) which is associated with increased morbidity and mortality. Atrial electromechanical delay (EMD) is a significant predictor of AF. The aim of this study was to assess the atrial EMD and diastolic functions in subclinical and overt hyperthyroidism by using tissue Doppler imaging (TDI). The study population consisted of 3 groups: group I (30 healthy subjects), group II (38 patients with subclinical hyperthyroidism), and group III (25 patients with overt hyperthyroidism). Atrial electromechanical coupling was measured with TDI. Standard echocardiographic measurements and parameters of diastolic function were obtained by conventional echocardiography and TDI. Intra- and inter-atrial EMD were significantly prolonged in subclinical and overt hyperthyroidism compared with control group (P = 0.03 and P hyperthyroidism. TSH level and mitral Em /Am ratio were found as independent predictors of atrial EMD. © 2013, Wiley Periodicals, Inc.

  20. Effect of variation of geometric parameters on the flow within a synthetic models of lower human airways

    Science.gov (United States)

    Espinosa Moreno, Andres Santiago; Duque Daza, Carlos Alberto

    2017-11-01

    The effects of variation of two geometric parameters, such as bifurcation angle and carina rounding radius, during the respiratory inhalation process, are studied numerically using two synthetic models of lower human airways. Laminar flow simulations were performed for six angles and three rounding radius, for 500, 1000, 1500 and 2000 for Reynolds numbers. Numerical results showed the existence of a direct relationship between the deformation of the velocity profiles (effect produced by the bifurcation) and the vortical structures observed through the secondary flow patterns. It is observed that the location of the vortices (and their related saddle point) is associated with the displacement of the velocity peak. On the other hand, increasing the angle and the rounding radius seems to bring about a growth of the pressure drop, which in turn displaces the distribution and peaks of the maximum shear stresses of the carina, that is, of the bifurcation point. Some physiological effects associated with the phenomena produced by these geometric variations are also discussed.

  1. Effects of strong earthquakes in variations of electrical and meteorological parameters of the near-surface atmosphere in Kamchatka region

    Science.gov (United States)

    Smirnov, S. E.; Mikhailova, G. A.; Mikhailov, Yu. M.; Kapustina, O. V.

    2017-09-01

    The diurnal variations in electrical (quasistatic electric field and electrical conductivity) and meteorological (temperature, pressure, relative humidity of the atmosphere, and wind speed) parameters, measured simultaneously before strong earthquakes in Kamchatka region (November 15, 2006, M = 8.3; January 13, 2007, M = 8.1; January 30, 2016, M = 7.2), are studied for the first time in detail. It is found that a successively anomalous increase in temperature, despite the negative regular trend in these winter months, was observed in the period of six-seven days before the occurrences of earthquakes. An anomalous temperature increase led to the formation of "winter thunderstorm" conditions in the near-surface atmosphere of Kamchatka region, which was manifested in the appearance of an anomalous, type 2 electrical signal, the amplification of and intensive variations in electrical conductivity, heavy precipitation (snow showers), high relative humidity of air, storm winds, and pressure changes. With the weak flow of natural heat radiation in this season, the observed dynamics of electric and meteorological processes can likely be explained by the appearance of an additional heat source of seismic nature.

  2. Electromechanical field effect transistors based on multilayer phosphorene nanoribbons

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Z.T., E-mail: jiangzhaotan@hotmail.com; Lv, Z.T.; Zhang, X.D.

    2017-06-21

    Based on the tight-binding Hamiltonian approach, we demonstrate that the electromechanical field effect transistors (FETs) can be realized by using the multilayer phosphorene nanoribbons (PNRs). The synergistic combination of the electric field and the external strains can establish the on–off switching since the electric field can shift or split the energy band, and the mechanical strains can widen or narrow the band widths. This kind of multilayer PNR FETs, much solider than the monolayer PNR one and more easily biased by different electric fields, has more transport channels consequently leading to the higher on–off current ratio or the higher sensitivity to the electric fields. Meanwhile, the strain-induced band-flattening will be beneficial for improving the flexibility in designing the electromechanical FETs. In addition, such electromechanical FETs can act as strain-controlled FETs or mechanical detectors for detecting the strains, indicating their potential applications in nano- and micro-electromechanical fields. - Highlights: • Electromechanical transistors are designed with multilayer phosphorene nanoribbons. • Electromechanical synergistic effect can establish the on–off switching more flexibly. • Multilayer transistors, solider and more easily biased, has more transport channels. • Electromechanical transistors can act as strain-controlled transistors or mechanical detectors.

  3. Seasonal and sex-specific variations in haematological parameters in 4 to 5.5-month-old infants in Guinea-Bissau, West Africa

    DEFF Research Database (Denmark)

    Bæk, Ole; Jensen, Kristoffer Jarlov; Andersen, Andreas

    2017-01-01

    Objective: This study investigated seasonal and sex-specific variations in the haematological parameters and established reference ranges for these parameters in healthy 4 to 5.5-month-old infants in Guinea-Bissau. Methods: Within a randomised trial of early measles vaccination, over a period of ...

  4. DISTRIBUTION OF WOODY VEGETATION ON SODA WASTE DUMPS IN RELATION TO SPATIAL VARIATION IN SELECTED PARAMETERS OF THE MINERAL COVER

    Directory of Open Access Journals (Sweden)

    Ewelina Zając

    2016-11-01

    Full Text Available Development of woody plants in the course of succession on reclaimed soda waste dumps by use of mineral cover was analyzed. The spatial variation in the thickness and granulometric composition of the mineral cover was analysed by the Kriging method. The statistical measurements and geostatistical analysis were used to create maps showing areal variability for the parameters analysed. Analysis of the development of woody vegetation was based on field work and raster layers created on the basis of aerial photographs. No link was found between the parameters of the mineral cover and the distribution and development of spontaneous woody vegetation. The species composition in the study area is limited, and dominated by pioneer species, mainly the expansive black locust (Robinia pseudoacacia. Given that the soda waste disposal site is to be used as urban green spaces, the target ecosystem structure must be considered and a suitable course of action selected: further reclamation procedures improving substrate quality and enrichment of the species composition of the tree stand, or management involving sustaining the current state while controlling the course of natural succession of vegetation.

  5. Optimization of process parameter variations on leakage current in in silicon-oninsulator vertical double gate mosfet device

    Directory of Open Access Journals (Sweden)

    K.E. Kaharudin

    2015-12-01

    Full Text Available This paper presents a study of optimizing input process parameters on leakage current (IOFF in silicon-on-insulator (SOI Vertical Double-Gate,Metal Oxide Field-Effect-Transistor (MOSFET by using L36 Taguchi method. The performance of SOI Vertical DG-MOSFET device is evaluated in terms of its lowest leakage current (IOFF value. An orthogonal array, main effects, signal-to-noise ratio (SNR and analysis of variance (ANOVA are utilized in order to analyze the effect of input process parameter variation on leakage current (IOFF. Based on the results, the minimum leakage current ((IOFF of SOI Vertical DG-MOSFET is observed to be 0.009 nA/µm or 9 ρA/µm while keeping the drive current (ION value at 434 µA/µm. Both the drive current (ION and leakage current (IOFF values yield a higher ION/IOFF ratio (48.22 x 106 for low power consumption application. Meanwhile, polysilicon doping tilt angle and polysilicon doping energy are recognized as the most dominant factors with each of the contributing factor effects percentage of 59% and 25%.

  6. Intra- and postoperative variation in ocular response analyzer parameters in keratoconic eyes after corneal cross-linking.

    Science.gov (United States)

    Vinciguerra, Paolo; Albè, Elena; Mahmoud, Ashraf M; Trazza, Silvia; Hafezi, Farhad; Roberts, Cynthia J

    2010-09-01

    To analyze intra- and postoperative variation in Ocular Response Analyzer (ORA, Reichert Ophthalmic Instruments) parameters in 24 keratoconic eyes undergoing corneal cross-linking (CXL). In a prospective clinical study, corneal hysteresis (CH), corneal resistance factor (CRF), peak 1 and peak 2 amplitude, corneal-compensated and Goldmann-correlated intraocular pressure (IOP) were evaluated using the ORA. The thinnest cornea point was measured with the Pentacam (Oculus Inc). Corneal topography and endothelial cell count were performed. Measurements were recorded at baseline; intraoperatively after epithelium removal, riboflavin impregnation, and ultraviolet A irradiation; and postoperatively after corneal re-epithelialization and at 1, 6, and 12 months. A statistically significant reduction of the thinnest cornea point from 462±23.24 μm was observed at the end of the CXL procedure intraoperatively and at 1- and 6-month follow-up (Pcornea point to 624±31.72 μm was found after re-epithelialization (P.05). The results showed a significant change in ORA parameters and the thinnest cornea point during and after the CXL procedure and a high correlation between peak amplitudes and corneal asymmetry, providing insight to the bioelastic and biomechanical behavior of the cornea during and after CXL. Copyright 2010, SLACK Incorporated.

  7. Erythrocyte Membrane Failure by Electromechanical Stress

    Directory of Open Access Journals (Sweden)

    E Du

    2018-01-01

    Full Text Available We envision that electrodeformation of biological cells through dielectrophoresis as a new technique to elucidate the mechanistic details underlying membrane failure by electrical and mechanical stresses. Here we demonstrate the full control of cellular uniaxial deformation and tensile recovery in biological cells via amplitude-modified electric field at radio frequency by an interdigitated electrode array in microfluidics. Transient creep and cyclic experiments were performed on individually tracked human erythrocytes. Observations of the viscoelastic-to-viscoplastic deformation behavior and the localized plastic deformations in erythrocyte membranes suggest that electromechanical stress results in irreversible membrane failure. Examples of membrane failure can be separated into different groups according to the loading scenarios: mechanical stiffening, physical damage, morphological transformation from discocyte to echinocyte, and whole cell lysis. These results show that this technique can be potentially utilized to explore membrane failure in erythrocytes affected by other pathophysiological processes.

  8. Solitary electromechanical pulses in Lobster neurons

    CERN Document Server

    Gonzalez-Perez, Alfredo; Budvytyte, Rima; Villagran-Vargas, Edgar; Jackson, Andrew D; Heimburg, Thomas

    2015-01-01

    Investigations of nerve activity have focused predominantly on electrical phenomena. Nerves, however, are thermodynamic systems, and changes in temperature and in the dimensions of the nerve can also be observed during the action potential. Measurements of heat changes during the action potential suggest that the nerve pulse shares many characteristics with an adiabatic pulse. In the past, experiments by Iwasa & Tasaki demonstrated small changes in nerve thickness and length during the action potential. Such findings have led to the suggestion that the action potential may be related to electromechanical solitons traveling without dissipation. Here, we present ultrasensitive AFM recordings of mechanical changes on the order of 0.2 - 1.2 nm in the giant axons of the lobster. When stimulated at opposite ends of the same axon, colliding action potentials pass through one another and do not annihilate. These observations are consistent with a mechanical interpretation of the nervous impulse.

  9. Electromechanically active polymer transducers: research in Europe

    DEFF Research Database (Denmark)

    Carpi, Federico; Graz, Ingrid; Jager, Edwin

    2013-01-01

    in two major families: ionic EAPs (activated by an electrically induced transport of ions and/or solvent) and electronic EAPs (activated by electrostatic forces). These polymers show interesting properties, such as sizable active strains and/or stresses in response to electrical driving, high mechanical......Smart materials and structures based on electromechanically active polymers (EAPs) represent a fast growing and stimulating field of research and development. EAPs are materials capable of changing dimensions and/or shape in response to suitable electrical stimuli. They are commonly classified...... on ionic and electronic EAPs. The contents, which span highly heterogeneous and cross diverse disciplines, such as physics, chemistry, material science and engineering, embrace size scales from nano to macro, and cover different areas, such as new materials, devices and applications. This collection...

  10. Scalable BDDC Algorithms for Cardiac Electromechanical Coupling

    KAUST Repository

    Pavarino, L. F.

    2017-03-17

    The spread of electrical excitation in the cardiac muscle and the subsequent contraction-relaxation process is quantitatively described by the cardiac electromechanical coupling model. The electrical model consists of the Bidomain system, which is a degenerate parabolic system of two nonlinear partial differential equations (PDEs) of reaction-diffusion type, describing the evolution in space and time of the intra- and extracellular electric potentials. The PDEs are coupled through the reaction term with a stiff system of ordinary differential equations (ODEs), the membrane model, which describes the flow of the ionic currents through the cellular membrane and the dynamics of the associated gating variables. The mechanical model consists of the quasi-static finite elasticity system, modeling the cardiac tissue as a nearly-incompressible transversely isotropic hyperelastic material, and coupled with a system of ODEs accounting for the development of biochemically generated active force.

  11. Phosphatidylserine exposure on stored red blood cells as a parameter for donor-dependent variation in product quality.

    Science.gov (United States)

    Dinkla, Sip; Peppelman, Malou; Van Der Raadt, Jori; Atsma, Femke; Novotný, Vera M J; Van Kraaij, Marian G J; Joosten, Irma; Bosman, Giel J C G M

    2014-04-01

    Exposure of phosphatidylserine on the outside of red blood cells contributes to recognition and removal of old and damaged cells. The fraction of phosphatidylserine-exposing red blood cells varies between donors, and increases in red blood cell concentrates during storage. The susceptibility of red blood cells to stress-induced phosphatidylserine exposure increases with storage. Phosphatidylserine exposure may, therefore, constitute a link between donor variation and the quality of red blood cell concentrates. In order to examine the relationship between storage parameters and donor characteristics, the percentage of phosphatidylserine-exposing red blood cells was measured in red blood cell concentrates during storage and in fresh red blood cells from blood bank donors. The percentage of phosphatidylserine-exposing red blood cells was compared with red blood cell susceptibility to osmotic stress-induced phosphatidylserine exposure in vitro, with the regular red blood cell concentrate quality parameters, and with the donor characteristics age, body mass index, haemoglobin level, gender and blood group. Phosphatidylserine exposure varies between donors, both on red blood cells freshly isolated from the blood, and on red blood cells in red blood cell concentrates. Phosphatidylserine exposure increases with storage time, and is correlated with stress-induced phosphatidylserine exposure. Increased phosphatidylserine exposure during storage was found to be associated with haemolysis and vesicle concentration in red blood cell concentrates. The percentage of phosphatidylserine-exposing red blood cells showed a positive correlation with the plasma haemoglobin concentration of the donor. The fraction of phosphatidylserine-exposing red blood cells is a parameter of red blood cell integrity in red blood cell concentrates and may be an indicator of red blood cell survival after transfusion. Measurement of phosphatidylserine exposure may be useful in the selection of donors and

  12. Phosphatidylserine exposure on stored red blood cells as a parameter for donor-dependent variation in product quality

    Science.gov (United States)

    Dinkla, Sip; Peppelman, Malou; van der Raadt, Jori; Atsma, Femke; Novotný, Vĕra M.J.; van Kraaij, Marian G.J.; Joosten, Irma; Bosman, Giel J.C.G.M.

    2014-01-01

    Background Exposure of phosphatidylserine on the outside of red blood cells contributes to recognition and removal of old and damaged cells. The fraction of phosphatidylserine-exposing red blood cells varies between donors, and increases in red blood cell concentrates during storage. The susceptibility of red blood cells to stress-induced phosphatidylserine exposure increases with storage. Phosphatidylserine exposure may, therefore, constitute a link between donor variation and the quality of red blood cell concentrates. Materials and methods In order to examine the relationship between storage parameters and donor characteristics, the percentage of phosphatidylserine-exposing red blood cells was measured in red blood cell concentrates during storage and in fresh red blood cells from blood bank donors. The percentage of phosphatidylserine-exposing red blood cells was compared with red blood cell susceptibility to osmotic stress-induced phosphatidylserine exposure in vitro, with the regular red blood cell concentrate quality parameters, and with the donor characteristics age, body mass index, haemoglobin level, gender and blood group. Results Phosphatidylserine exposure varies between donors, both on red blood cells freshly isolated from the blood, and on red blood cells in red blood cell concentrates. Phosphatidylserine exposure increases with storage time, and is correlated with stress-induced phosphatidylserine exposure. Increased phosphatidylserine exposure during storage was found to be associated with haemolysis and vesicle concentration in red blood cell concentrates. The percentage of phosphatidylserine-exposing red blood cells showed a positive correlation with the plasma haemoglobin concentration of the donor. Discussion The fraction of phosphatidylserine-exposing red blood cells is a parameter of red blood cell integrity in red blood cell concentrates and may be an indicator of red blood cell survival after transfusion. Measurement of phosphatidylserine

  13. A Toolkit to Study Sensitivity of the Geant4 Predictions to the Variations of the Physics Model Parameters

    Energy Technology Data Exchange (ETDEWEB)

    Fields, Laura [Fermilab; Genser, Krzysztof [Fermilab; Hatcher, Robert [Fermilab; Kelsey, Michael [SLAC; Perdue, Gabriel [Fermilab; Wenzel, Hans [Fermilab; Wright, Dennis H. [SLAC; Yarba, Julia [Fermilab

    2017-08-21

    Geant4 is the leading detector simulation toolkit used in high energy physics to design detectors and to optimize calibration and reconstruction software. It employs a set of carefully validated physics models to simulate interactions of particles with matter across a wide range of interaction energies. These models, especially the hadronic ones, rely largely on directly measured cross-sections and phenomenological predictions with physically motivated parameters estimated by theoretical calculation or measurement. Because these models are tuned to cover a very wide range of possible simulation tasks, they may not always be optimized for a given process or a given material. This raises several critical questions, e.g. how sensitive Geant4 predictions are to the variations of the model parameters, or what uncertainties are associated with a particular tune of a Geant4 physics model, or a group of models, or how to consistently derive guidance for Geant4 model development and improvement from a wide range of available experimental data. We have designed and implemented a comprehensive, modular, user-friendly software toolkit to study and address such questions. It allows one to easily modify parameters of one or several Geant4 physics models involved in the simulation, and to perform collective analysis of multiple variants of the resulting physics observables of interest and comparison against a variety of corresponding experimental data. Based on modern event-processing infrastructure software, the toolkit offers a variety of attractive features, e.g. flexible run-time configurable workflow, comprehensive bookkeeping, easy to expand collection of analytical components. Design, implementation technology, and key functionalities of the toolkit are presented and illustrated with results obtained with Geant4 key hadronic models.

  14. Electromechanical properties of multi-walled carbon nano-tubes; Proprietes electromecaniques des nanotubes de carbone multiparois

    Energy Technology Data Exchange (ETDEWEB)

    Lefevre, R.

    2005-12-15

    In this PhD thesis, we tackled theoretically and experimentally the problem of designing nano-electromechanical systems (NEMS) based on multi-walled carbon nano-tubes (MWCNTs). Furthermore, we applied our know-how to perform components like switches. We developed a theoretical model to describe the deflection of a suspended MWCNT stressed by an attractive electrostatic force. Our model highlights a scaling law linking up the electrostatic deflection, geometrical, electrical and physical parameters of MWCNTs based NEMS. This result constitutes a practical designing tool because it predicts their electromechanical behaviour on a 'large' range of operational parameters. At the same time, we developed several processes to fabricate nano-structures incorporating a suspended MWCNT electrostatically actuated. Among these different structures, the simplest was used to develop a method for probing electromechanical properties of MWCNTs. Our method is based on atomic force microscopy measurements on a doubly clamped suspended MWCNT electrostatically deflected by a drive voltage. These measurements show clearly for different MWCNTs (different diameter and length) the existence of such scaling law in agreement with the continuum model prediction. From these results, we extracted the Young's modulus of MWCNTs. For diameters smaller than 30 nm it is constant and its average value equals 400 GPa. Above, we observed a strong decrease that could be explained by the entry in a non-linear regime of deformation. Finally, we show the realization of an electromechanical switch based on a suspended MWCNT which presents good switching behaviour. (author)

  15. Investigation into the electromechanical properties of dielectric elastomers subjected to pre-stressing.

    Science.gov (United States)

    Jiang, Liang; Betts, Anthony; Kennedy, David; Jerrams, Stephen

    2015-04-01

    Dielectric elastomers (DEs) are being exploited for biological applications such as artificial blood pumps, biomimetic grippers and biomimetic robots. Generally, polyacrylate and silicone rubber (SR) are the most widely used materials for fabricating DEs in terms of mixing with other polymers or compounding them with highly dielectric particles. Furthermore, pre-stretch offers an effective approach to increasing actuated strain and dielectric strength and eliminating 'pull-in' instability. In the work described here, a comparison in electromechanical properties was made between SR/10% barium titanate (BaTiO3) and commercial VHB 4910. Trends in these dielectric parameters are shown graphically for variation in pre-stretch ratio (λpre). It was found that permittivity of SR/10% BaTiO3 was independent of frequency, whereas permittivity was frequency-independent due to the polarization of polymer chains. The maximum deformation and the coupling efficiency for SR/10% BaTiO3 can be achieved at a pre-stretch ratio between 1.6 and 1.9. For VHB 4910, they can be obtained in the pre-stretch ratio range from 2.6 to 3.0. A maximum energy density of 0.05MJ/m(3) was achieved by SR/10% BaTiO3 (λpre=1.6) and VHB 4910 (λpre=3.4). The findings provide an insight into critical pre-stretch ratios required for a range of applications of DEs based on silicone and the commercially available polyacrylate VHB 4910. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Analysis method and principle of dual-mode electro-mechanical variable transmission program

    Science.gov (United States)

    Li, Hongcai; Yan, Qingdong; Xiang, Changle; Wang, Weida

    2012-05-01

    Automotive industry, as an important pillar of the national economy, has been rapidly developing in recent years. But proplems such as energy comsumption and environmental pollution are posed at the same time. Electro-mechanical variable transmission system is considered one of avilable workarounds. It is brought forward a kind of design methods of dual-mode electro-mechanical variable transmission system rotational speed characteristics and dual-mode drive diagrams. With the motor operating behavior of running in four quadrants and the speed characteristics of the simple internal and external meshing single planetary gear train, four kinds of dual-mode electro-mechanical transmission system scheme are designed. And the velocity, torque and power characteristics of one of the programs are analyzed. The magnitude of the electric split-flow power is an important factor which influences the system performance, so in the parameters matching design, it needs to reduce the power needs under the first mode of the motor. The motor, output rotational speed range and the position of the mode switching point have relationships with the characteristics design of the planetary gear set. The analysis method is to provide a reference for hybrid vehicles' design. As the involved rotational speed and torque relationships are the natural contact of every part of transmission system, a theory basis of system program and performance analysis is provided.

  17. Seasonal variations of carbonate system parameters and nutrients at the shellfish-farming bays along the south coast of Korea

    Science.gov (United States)

    Shim, JeongHee; Shim, Jeong-Min; Lee, Yong-Hwa

    2017-04-01

    About 80 90% of the annual mass production of shellfish in Korea are cultured at the inner bays including Jinhae, Tongyeong and Geoje regions, along the south coast of Korea. To understand coastal carbon and nutrients cycles and those effects/feedbacks on shellfish farming, carbonate (DIC, TA and pH) and environmental parameters were observed at Jinhae, Tongyeong and Geoje Bays 4 times (in Feb., Aug. 2014, Apr. and Oct. 2015 and are considered representative of winter, summer, spring and fall respectively). Surface temperature in the bays showed clear seasonal variation with about 6 12°C and 24 29°C in Feb. and Aug. 2014, respectively and 14 18°C and 22 26°C in Apr. and in Oct. 2015, respectively. Surface pHNBS also ranged with about 8.20 8.53 and 7.28 8.95 in Feb. and Aug. 2014, and 8.04 8.40 and 7.91 8.32 in Apr. and in Oct. 2015. High pH with low salinity in summer resulted from input of land discharge in rainy seasons, however high pH at small bays in Apr. and Oct. 2015 resulted from massive primary production by phytoplankton bloom, supported by high chlorophyll a concentrations. Seasonal variations of DIC and phosphate in the surface and bottom waters correlated largely with salinity, higher in winter and lower in summer. Specifically in shellfish (specially, oyster and mussel) growing season, aragonite saturation state (Ωarag) in bottom water ranged about 0.2 2.9 (mean 2.1) and 2.2 5.0 (mean 3.2) in Feb. 2014 and Oct. 2015, respectively, suggesting low pH environments arose seasonally in coastal area due to some mechanisms. These results suggest that seasonal ocean acidification state might seriously affect shell growth, mass production and thus shellfish industry along the south coast of Korea.

  18. Arterial pressure variations as parameters of brain perfusion in response to central blood volume depletion and repletion

    Science.gov (United States)

    Bronzwaer, Anne-Sophie G. T.; Stok, Wim J.; Westerhof, Berend E.; van Lieshout, Johannes J.

    2014-01-01

    Rationale: A critical reduction in central blood volume (CBV) is often characterized by hemodynamic instability. Restoration of a volume deficit may be established by goal-directed fluid therapy guided by respiration-related variation in systolic- and pulse pressure (SPV and PPV). Stroke volume index (SVI) serves as a surrogate end-point of a fluid challenge but tissue perfusion itself has not been addressed. Objective: To delineate the relationship between arterial pressure variations, SVI and regional brain perfusion during CBV depletion and repletion in spontaneously breathing volunteers. Methods: This study quantified in 14 healthy subjects (11 male) the effects of CBV depletion [by 30 and 70 degrees passive head-up tilt (HUT)] and a fluid challenge (by tilt back) on CBV (thoracic admittance), mean middle cerebral artery (MCA) blood flow velocity (Vmean), SVI, cardiac index (CI), PPV, and SPV. Results: PPV (103 ± 89%, p pressure. The reduction in MCAVmean correlated to the fall in SVI (R2 = 0.52, p < 0.0001) and inversely to PPV and SPV [R2 = 0.46 (p < 0.0001) and R2 = 0.45 (p < 0.0001), respectively]. PPV and SPV predicted a ≥15% reduction in MCAVmean and SVI with comparable sensitivity (67/67% vs. 63/68%, respectively) and specificity (89/94 vs. 89/94%, respectively). A rapid fluid challenge by tilt-back restored all parameters to baseline values within 1 min. Conclusion: In spontaneously breathing subjects, a reduction in MCAVmean was related to an increase in PPV and SPV during graded CBV depletion and repletion. Specifically, PPV and SPV predicted changes in both SVI and MCAVmean with comparable sensitivity and specificity, however the predictive value is limited in spontaneously breathing subjects. PMID:24795652

  19. Electromechanical behavior of polyaniline/poly (vinyl alcohol) blend films under static, dynamic and time-dependent strains

    Science.gov (United States)

    Akhilesan, S.; Lakshmana Rao, C.; Varughese, S.

    2014-07-01

    We report on the experimentally observed electrical conductivity enhancement in polyaniline/poly (vinyl alcohol) blend films under uniaxial tensile loading. Polyaniline (PANI) is an intrinsically conducting polymer, which does not form stretchable free-standing films easily and hence its electromechanical characterization is a challenge. Blending of PANI with other insulating polymers is a good choice to overcome the processability problem. We report the electromechanical response of solution blended and HCl doped PANI/PVA blends subjected to uniaxial, static, dynamic and time-dependent tensile loading. The demonstrated viscoelastic and morphological contributions of the component polymers to the electrical conductivity behavior in these blends could lead to interesting applications in strain sensors and flexible electronics. The reversibility of the electromechanical response under dynamic strain is found to increase in blends with higher PANI content. Time-dependent conductivity studies during mechanical stress relaxation reveal that variations in the micro-domain ordering and the relative relaxation rate of the individual polymer phases can give rise to interesting electrical conductivity changes in PANI blends. From morphological and electrical conductivity studies, we show that PANI undergoes primary and secondary agglomeration behavior in these blends that contributes to the changes in conductivity behavior during the deformation. A 3D variable range hopping (VRH) process, which uses a deformable core and shell concept based on blend morphology analysis, is used to explain the experimentally observed electromechanical behavior.

  20. Prognostic Health-Management System Development for Electromechanical Actuators

    Data.gov (United States)

    National Aeronautics and Space Administration — Electro-mechanical actuators (EMAs) have been gaining increased acceptance as safety-critical actuation devices in the next generation of aircraft and spacecraft....

  1. NASA Electrical, Electronic and Electromechanical (EEE) Parts Assurance, An Overview

    Science.gov (United States)

    Label, Kenneth A.; Sampson, Michael J.

    2017-01-01

    This presentation will cover NASA Electrical, Electronic and Electromechanical (EEE) Parts Assurance Structure, NASA Electronic Parts and Packaging (NEPP) Program, NASA Electronic Parts Assurance Group (NEPAG), examples of assurance challenges, and future challenges.

  2. Coupled electromechanical model of an imperfect piezoelectric vibrating cylinder gyroscope

    CSIR Research Space (South Africa)

    Loveday, PW

    1996-01-01

    Full Text Available Coupled electromechanical equations of motion, describing the dynamics of a vibrating cylinder gyroscope, are derived using Hamilton's principle and the Rayleigh-Ritz method. The vibrating cylinder gyroscope comprises a thin walled steel cylinder...

  3. Digital system accurately controls velocity of electromechanical drive

    Science.gov (United States)

    Nichols, G. B.

    1965-01-01

    Digital circuit accurately regulates electromechanical drive mechanism velocity. The gain and phase characteristics of digital circuits are relatively unimportant. Control accuracy depends only on the stability of the input signal frequency.

  4. Mathematical modeling of electromechanical processes in a brushless DC motor

    Directory of Open Access Journals (Sweden)

    V.I. Tkachuk

    2014-03-01

    Full Text Available On the basis of initial assumptions, a mathematical model that describes electromechanical processes in a brushless DC electric motor with a salient-pole stator and permanent-magnet excitation is created.

  5. Mathematical modeling of electromechanical processes in a brushless DC motor

    OpenAIRE

    V.I. Tkachuk; V.I. Zhuk

    2014-01-01

    On the basis of initial assumptions, a mathematical model that describes electromechanical processes in a brushless DC electric motor with a salient-pole stator and permanent-magnet excitation is created.

  6. Seasonal variation in meteorological parameters and office, ambulatory and home blood pressure: predicting factors and clinical implications.

    Science.gov (United States)

    Stergiou, George S; Myrsilidi, Aikaterini; Kollias, Anastasios; Destounis, Antonios; Roussias, Leonidas; Kalogeropoulos, Petros

    2015-12-01

    This study investigated the relationship between seasonal variations in blood pressure (BP) and the corresponding changes in meteorological parameters and weather-induced patients' discomfort. Hypertensives on stable treatment were assessed in winter-1, summer and winter-2 with clinic (CBP), home (HBP) and 24-hour ambulatory BP (ABP). Discomfort indices derived from temperature, humidity and atmospheric pressure that reflected subjects' discomfort were evaluated. Symptomatic orthostatic hypotension was assessed with a questionnaire. Sixty subjects (mean age 65.1±8.8 [s.d.], 39 men) were analyzed. CBP, HBP and daytime ABP were lower in summer than in winter (P<0.01). Nighttime ABP was unchanged, which resulted in a 55% higher proportion of non-dippers (P<0.001). All the discomfort indices that reflected weather-induced subjects' discomfort were higher in summer (P<0.05) and systolic daytime ABP was <110 mm Hg in 15 subjects (25%). Seasonal changes in temperature and the discomfort indices were correlated with BP changes (P<0.05). Multivariate analyses revealed that winter BP levels, seasonal differences in temperature, female gender and the use of diuretics predicted the summer BP decline. In conclusion, all aspects of the BP profile, except nighttime ABP, are reduced in summer, resulting in an increased prevalence of non-dippers in summer with unknown consequences. Seasonal BP changes are influenced by changes in meteorological parameters, anthropometric and treatment characteristics. Trials are urgently needed to evaluate the clinical relevance of excessive BP decline in summer and management guidelines for practicing physicians should be developed.

  7. In-vitro experiments to characterize ventricular electromechanics

    Directory of Open Access Journals (Sweden)

    Arnold Robert

    2016-09-01

    Full Text Available Computer simulation turns out to be beneficial when clinical data lack spatio-temporal resolution or parameters cannot be measured at all. To derive trustworthy results, these in-silico models have to thoroughly parameterized and validated. In this work we present data from a simplified in-vitro setup for characterizing ventricular electromechanics. Right ventricular papillary muscles from New Zealand rabbits were isolated and stretched from slack length to lmax, i.e. the muscle length at maximum active force development. Active stress development showed an almost linear increase for moderate strain (90–100% of lmax and a significant decrease for larger strain (100–105% of lmax. Passive strain development showed a nonlinear increase. Conduction velocity CV showed an increase of ≈10% between low and moderate strain and no significant decrease beyond. Fitting active active stress-strain relationship using a 5th-order polynomial yielded adequate results for moderate and high strain values, whereas fitting using a logistic function yielded more reasonable results for low strain values. Passive stress-strain relationship was satisfactorily fitted using an exponential function.

  8. Improvement of diode parameters in Al/n-Si Schottky diodes with Coronene interlayer using variation of the illumination intensity

    Science.gov (United States)

    Pakma, Osman; Çavdar, Şükrü; Koralay, Haluk; Tuğluoğlu, Nihat; Faruk Yüksel, Ömer

    2017-12-01

    In present work, Coronene thin films on Si wafer have been deposited by the spin coating method. It has been ultimately produced Al/Coronene/n-Si/In Schottky diode. Current-voltage (I-V) measurements have been used to determine the effect of illumination intensity in the Schottky diodes. The barrier height (ΦB) values increased as ideality factor (n) values decreased with a increase in illumination intensity. The ΦB values have been found to be 0.697 and 0.755 eV at dark and 100 mW/cm2, respectively. The n values have been found to be 2.81 and 2.07 at dark and 100 mW/cm2, respectively. Additionally, the series resistance (Rs) values from modified Norde method and interface state density (Nss) values using current-voltage measurements have been determined. The values of Rs have been found to be 1924 and 5094 Ω at dark and 100 mW/cm2, respectively. The values of Nss have been found to be 4.76 × 1012 and 3.15 × 1012 eV-1 cm-2 at dark and 100 mW/cm2, respectively. The diode parameters are improved by applying the variation of illumination intensity to the formed Schottky diodes.

  9. Assessment of wall elasticity variations on intraluminal haemodynamics in descending aortic dissections using a lumped-parameter model.

    Science.gov (United States)

    Rudenick, Paula A; Bijnens, Bart H; Segers, Patrick; García-Dorado, David; Evangelista, Arturo

    2015-01-01

    Descending aortic dissection (DAD) is associated with high morbidity and mortality rates. Aortic wall stiffness is a variable often altered in DAD patients and potentially involved in long-term outcome. However, its relevance is still mostly unknown. To gain more detailed knowledge of how wall elasticity (compliance) might influence intraluminal haemodynamics in DAD, a lumped-parameter model was developed based on experimental data from a pulsatile hydraulic circuit and validated for 8 clinical scenarios. Next, the variations of intraluminal pressures and flows were assessed as a function of wall elasticity. In comparison with the most rigid-wall case, an increase in elasticity to physiological values was associated with a decrease in systolic and increase in diastolic pressures of up to 33% and 63% respectively, with a subsequent decrease in the pressure wave amplitude of up to 86%. Moreover, it was related to an increase in multidirectional intraluminal flows and transition of behaviour as 2 parallel vessels towards a vessel with a side-chamber. The model supports the extremely important role of wall elasticity as determinant of intraluminal pressures and flow patterns for DAD, and thus, the relevance of considering it during clinical assessment and computational modelling of the disease.

  10. Does diurnal variation affect the first trimester fetal aneuploidy screening test biochemical parameters of fetuses with normal nuchal translucency?

    Science.gov (United States)

    Karsli, Mehmet Fatih; Cakmak, Bulent; Seckin, Kerem Doga; Akkas Yilmaz, Elif; Akgul, Gurcan; Togrul, Cihan; Kucukozkan, Tuncay

    2016-01-01

    The purpose of this study was to investigate the effect of diurnal variation on biochemical results of first trimester aneuploidy screening test. A total of 2725 singleton pregnant female, who had normal fetal nuchal translucency (NT) thickness, were included in the study during this period. Individuals were divided into two groups according to the sampling time (morning group: 09:00-11:00 am and afternoon group: 02:00-04:00 pm). Hormonal parameters (free-beta human chorionic gonadotropin [free β-hCG] and pregnancy-associated plasma protein-A [PAPP-A] multiples of median [MoM] levels) of first trimester (11(+0)-13(+6) weeks) combined aneuploidy screening test were compared between morning and afternoon groups. PAPP-A MoM levels were significantly lower in the afternoon group when compared to the morning group (p = 0.001), whereas free β-hCG MoM levels were similar in the both groups (p = 0.392). Rate of high risk for Down syndrome (Combine risk >1/300) and amniocentesis ratio were found higher in the afternoon group than morning group, but there were no difference between groups for the number of fetuses with Down syndrome. Receiving the venous blood sample for first trimester aneuploidy screening test in the afternoon causes low PAPP-A MoM levels.

  11. Optimization of Auger System in Shallow Electromechanical Auger Drills

    Science.gov (United States)

    Hong, Jialin; Talalay, Pavel

    2017-04-01

    In recent decades, electromechanical auger drilling has become a very popular method of ice core sampling, and the drilling sites are spread all over the world, covering the whole glacial distribution from polar to high-mountain regions. However, auger systems were usually determined by experience, and the main parameters (helix angle of the fights and rotational speed) are varied in a wide range from drill to drill. The external parameters which have a large influence on the efficiency of the cuttings transportation are friction coefficients between ice inner/outer barrels and the size distribution of ice cuttings. Totally 424 linear friction experiments with common and promising slider materials for auger drills were carried out at the wide range of temperatures observed in glaciers from -60 to 0 C. The coefficient of friction increases with decreasing of temperature but this dependence is not monotonous. To determine the patterns of ice cuttings, sixteen ice cuttings were sampled in the course of drilling in natural lake ice. The size distribution of the cuttings has an asymmetrical shape. Approximately half of the ice cuttings by weight are classified as small sized (sieving samples, the ice cuttings have prolate form with a ratio between the major and minor axis 1.55 in average. In order to choose the optimal auger parameters, the discrete element method is used to analyze the performance of cuttings transportation for different rotation speeds in the range 50-200 rpm and auger angles in the range 25-45°. Validation of optimal auger system were undertaken by field testes at high elevation glacier (5600m) in Xinjiang, China.

  12. Precision and within- and between-day variation of bioimpedance parameters in children aged 2-14 years

    DEFF Research Database (Denmark)

    Andersen, Trine B; Jødal, Lars; Arveschoug, Anne

    2011-01-01

    BACKGROUND & AIMS: Bioimpedance spectroscopy (BIS) offers the possibility to perform rapid estimates of fluid distribution and body composition. Few studies, however, have addressed the precision and biological variation in a pediatric population. Our objectives were to evaluate precision, variat...

  13. Electromechanical wave imaging and electromechanical wave velocity estimation in a large animal model of myocardial infarction

    Science.gov (United States)

    Costet, Alexandre; Melki, Lea; Sayseng, Vincent; Hamid, Nadira; Nakanishi, Koki; Wan, Elaine; Hahn, Rebecca; Homma, Shunichi; Konofagou, Elisa

    2017-12-01

    Echocardiography is often used in the clinic for detection and characterization of myocardial infarction. Electromechanical wave imaging (EWI) is a non-invasive ultrasound-based imaging technique based on time-domain incremental motion and strain estimation that can evaluate changes in contractility in the heart. In this study, electromechanical activation is assessed in infarcted heart to determine whether EWI is capable of detecting and monitoring infarct formation. Additionally, methods for estimating electromechanical wave (EW) velocity are presented, and changes in the EW propagation velocity after infarct formation are studied. Five (n  =  5) adult mongrels were used in this study. Successful infarct formation was achieved in three animals by ligation of the left anterior descending (LAD) coronary artery. Dogs were survived for a few days after LAD ligation and monitored daily with EWI. At the end of the survival period, dogs were sacrificed and TTC (tetrazolium chloride) staining confirmed the formation and location of the infarct. In all three dogs, as soon as day 1 EWI was capable of detecting late-activated and non-activated regions, which grew over the next few days. On final day images, the extent of these regions corresponded to the location of infarct as confirmed by staining. EW velocities in border zones of infarct were significantly lower post-infarct formation when compared to baseline, whereas velocities in healthy tissues were not. These results indicate that EWI and EW velocity might help with the detection of infarcts and their border zones, which may be useful for characterizing arrhythmogenic substrate.

  14. Experimental investigation on the effect of intake air temperature and air-fuel ratio on cycle-to-cycle variations of HCCI combustion and performance parameters

    Energy Technology Data Exchange (ETDEWEB)

    Maurya, Rakesh Kumar; Agarwal, Avinash Kumar [Engine Research Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016 (India)

    2011-04-15

    Combustion in HCCI engines is a controlled auto ignition of well-mixed fuel, air and residual gas. Since onset of HCCI combustion depends on the auto ignition of fuel/air mixture, there is no direct control on the start of combustion process. Therefore, HCCI combustion becomes unstable rather easily, especially at lower and higher engine loads. In this study, cycle-to-cycle variations of a HCCI combustion engine fuelled with ethanol were investigated on a modified two-cylinder engine. Port injection technique is used for preparing homogeneous charge for HCCI combustion. The experiments were conducted at varying intake air temperatures and air-fuel ratios at constant engine speed of 1500 rpm and P-{theta} diagram of 100 consecutive combustion cycles for each test conditions at steady state operation were recorded. Consequently, cycle-to-cycle variations of the main combustion parameters and performance parameters were analyzed. To evaluate the cycle-to-cycle variations of HCCI combustion parameters, coefficient of variation (COV) of every parameter were calculated for every engine operating condition. The critical optimum parameters that can be used to define HCCI operating ranges are 'maximum rate of pressure rise' and 'COV of indicated mean effective pressure (IMEP)'. (author)

  15. Superconducting circuitry for quantum electromechanical systems

    Science.gov (United States)

    LaHaye, Matthew D.; Rouxinol, Francisco; Hao, Yu; Shim, Seung-Bo; Irish, Elinor K.

    2015-05-01

    Superconducting systems have a long history of use in experiments that push the frontiers of mechanical sensing. This includes both applied and fundamental research, which at present day ranges from quantum computing research and e orts to explore Planck-scale physics to fundamental studies on the nature of motion and the quantum limits on our ability to measure it. In this paper, we first provide a short history of the role of superconducting circuitry and devices in mechanical sensing, focusing primarily on efforts in the last decade to push the study of quantum mechanics to include motion on the scale of human-made structures. This background sets the stage for the remainder of the paper, which focuses on the development of quantum electromechanical systems (QEMS) that incorporate superconducting quantum bits (qubits), superconducting transmission line resonators and flexural nanomechanical elements. In addition to providing the motivation and relevant background on the physical behavior of these systems, we discuss our recent efforts to develop a particular type of QEMS that is based upon the Cooper-pair box (CPB) and superconducting coplanar waveguide (CPW) cavities, a system which has the potential to serve as a testbed for studying the quantum properties of motion in engineered systems.

  16. A COMPARATIVE ANALYSIS OF CONSTRUCTIVE SCHEMES OF LINEAR IMPACTOR ELECTROMECHANICAL CONVERTERS COMBINED TYPE

    Directory of Open Access Journals (Sweden)

    V.F. Bolyukh

    2015-08-01

    Full Text Available The concept of linear impactor electromechanical converter combined type with a single inductor excited by capacitive energy storage aperiodic pulse is proposed. The concept combines induction and electromagnetic converters. For the synthesis of the converter parameters the Monte Carlo method is used. As the objective function is selected the maximum value of the total pulse the electrodynamic and electromagnetic force acting on the combined anchor. The features and characteristics of electro-magnetic field converters are identified. Considered several of selection policies and by means of integral index identified the most and least efficient design of the converter circuit.

  17. Electromechanical coupling factor of capacitive micromachined ultrasonic transducers

    Science.gov (United States)

    Caronti, Alessandro; Carotenuto, Riccardo; Pappalardo, Massimo

    2003-01-01

    Recently, a linear, analytical distributed model for capacitive micromachined ultrasonic transducers (CMUTs) was presented, and an electromechanical equivalent circuit based on the theory reported was used to describe the behavior of the transducer [IEEE Trans. Ultrason. Ferroelectr. Freq. Control 49, 159-168 (2002)]. The distributed model is applied here to calculate the dynamic coupling factor kw of a lossless CMUT, based on a definition that involves the energies stored in a dynamic vibration cycle, and the results are compared with those obtained with a lumped model. A strong discrepancy is found between the two models as the bias voltage increases. The lumped model predicts an increasing dynamic k factor up to unity, whereas the distributed model predicts a more realistic saturation of this parameter to values substantially lower. It is demonstrated that the maximum value of kw, corresponding to an operating point close to the diaphragm collapse, is 0.4 for a CMUT single cell with a circular membrane diaphragm and no parasitic capacitance (0.36 for a cell with a circular plate diaphragm). This means that the dynamic coupling factor of a CMUT is comparable to that of a piezoceramic plate oscillating in the thickness mode. Parasitic capacitance decreases the value of kw, because it does not contribute to the energy conversion. The effective coupling factor keff is also investigated, showing that this parameter coincides with kw within the lumped model approximation, but a quite different result is obtained if a computation is made with the more accurate distributed model. As a consequence, keff, which can be measured from the transducer electrical impedance, does not give a reliable value of the actual dynamic coupling factor.

  18. Electromechanically active polymer transducers: research in Europe

    Science.gov (United States)

    Carpi, Federico; Graz, Ingrid; Jager, Edwin; Ladegaard Skov, Anne; Vidal, Frédéric

    2013-10-01

    Smart materials and structures based on electromechanically active polymers (EAPs) represent a fast growing and stimulating field of research and development. EAPs are materials capable of changing dimensions and/or shape in response to suitable electrical stimuli. They are commonly classified in two major families: ionic EAPs (activated by an electrically induced transport of ions and/or solvent) and electronic EAPs (activated by electrostatic forces). These polymers show interesting properties, such as sizable active strains and/or stresses in response to electrical driving, high mechanical flexibility, low density, structural simplicity, ease of processing and scalability, no acoustic noise and, in most cases, low costs. Since many of these characteristics can also describe natural muscle tissues from an engineering standpoint, it is not surprising that EAP transducers are sometimes also referred to as 'muscle-like smart materials' or 'artificial muscles'. They are used not only to generate motion, but also to sense or harvest energy from it. In particular, EAP electromechanical transducers are studied for applications that can benefit from their 'biomimetic' characteristics, with possible usages from the micro- to the macro-scale, spanning several disciplines, such as mechatronics, robotics, automation, biotechnology and biomedical engineering, haptics, fluidics, optics and acoustics. Currently, the EAP field is just undergoing its initial transition from academic research into commercialization, with companies starting to invest in this technology and the first products appearing on the market. This focus issue is intentionally aimed at gathering contributions from the most influential European groups working in the EAP field. In fact, today Europe hosts the broadest EAP community worldwide. The rapid expansion of the EAP field in Europe, where it historically has strong roots, has stimulated the creation of the 'European Scientific Network for Artificial

  19. Personalization of a cardiac electromechanical model using reduced order unscented Kalman filtering from regional volumes.

    Science.gov (United States)

    Marchesseau, S; Delingette, H; Sermesant, M; Cabrera-Lozoya, R; Tobon-Gomez, C; Moireau, P; Figueras i Ventura, R M; Lekadir, K; Hernandez, A; Garreau, M; Donal, E; Leclercq, C; Duckett, S G; Rhode, K; Rinaldi, C A; Frangi, A F; Razavi, R; Chapelle, D; Ayache, N

    2013-10-01

    Patient-specific cardiac modeling can help in understanding pathophysiology and therapy planning. However it requires to combine functional and anatomical data in order to build accurate models and to personalize the model geometry, kinematics, electrophysiology and mechanics. Personalizing the electromechanical coupling from medical images is a challenging task. We use the Bestel-Clément-Sorine (BCS) electromechanical model of the heart, which provides reasonable accuracy with a reasonable number of parameters (14 for each ventricle) compared to the available clinical data at the organ level. We propose a personalization strategy from cine MRI data in two steps. We first estimate global parameters with an automatic calibration algorithm based on the Unscented Transform which allows to initialize the parameters while matching the volume and pressure curves. In a second step we locally personalize the contractilities of all AHA (American Heart Association) zones of the left ventricle using the reduced order unscented Kalman filtering on Regional Volumes. This personalization strategy was validated synthetically and tested successfully on eight healthy and three pathological cases. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Cardiac Electromechanical Models: From Cell to Organ

    Directory of Open Access Journals (Sweden)

    Natalia A Trayanova

    2011-08-01

    Full Text Available The heart is a multiphysics and multiscale system that has driven the development of the most sophisticated mathematical models at the frontiers of computation physiology and medicine. This review focuses on electromechanical (EM models of the heart from the molecular level of myofilaments to anatomical models of the organ. Because of the coupling in terms of function and emergent behaviors at each level of biological hierarchy, separation of behaviors at a given scale is difficult. Here, a separation is drawn at the cell level so that the first half addresses subcellular/single cell models and the second half addresses organ models. At the subcelluar level, myofilament models represent actin-myosin interaction and Ca-based activation. Myofilament models and their refinements represent an overview of the development in the field. The discussion of specific models emphasizes the roles of cooperative mechanisms and sarcomere length dependence of contraction force, considered the cellular basis of the Frank-Starling law. A model of electrophysiology and Ca handling can be coupled to a myofilament model to produce an EM cell model, and representative examples are summarized to provide an overview of the progression of field. The second half of the review covers organ-level models that require solution of the electrical component as a reaction-diffusion system and the mechanical component, in which active tension generated by the myocytes produces deformation of the organ as described by the equations of continuum mechanics. As outlined in the review, different organ-level models have chosen to use different ionic and myofilament models depending on the specific application; this choice has been largely dictated by compromises between model complexity and computational tractability. The review also addresses application areas of EM models such as cardiac resynchronization therapy and the role of mechano-electric coupling in arrhythmias and

  1. Tunable actuation of dielectric elastomer by electromechanical loading rates

    Science.gov (United States)

    Li, Guorui; Zhang, Mingqi; Chen, Xiangping; Yang, Xuxu; Wong, Tuck-Whye; Li, Tiefeng; Huang, Zhilong

    2017-10-01

    Dielectric elastomer (DE) membranes are able to self-deform with the application of an electric field through the thickness direction. In comparison to conventional rigid counterparts, soft actuators using DE provide a variety of advantages such as high compliance, low noise, and light weight. As one of the challenges in the development of DE actuating devices, tuning the electromechanical actuating behavior is crucial in order to achieve demanded loading paths and to avoid electromechanical failures. In this paper, our experimental results show that the electromechanical loading conditions affect the actuating behaviors of the DE. The electrical actuating force can be tuned by 29.4% with the control of the electrical charging rate. In addition, controllable actuations have been investigated by the mechanical model in manipulating the electromechanical loading rate. The calculated results agree well with the experimental data. Lastly, it is believed that the mechanisms of controlling the electromechanical loading rate may serve as a guide for the design of DE devices and high performance soft robots in the near future.

  2. A variational constitutive framework for the nonlinear viscoelastic response of a dielectric elastomer

    KAUST Repository

    Khan, Kamran

    2012-11-10

    We formulate a variational constitutive framework that accounts for nonlinear viscous behavior of electrically sensitive polymers, specifically Dielectric Elastomers (DEs), under large deformation. DEs are highly viscoelastic and their actuation response is greatly affected in dynamic applications. We used the generalized Maxwell model to represent the viscoelastic response of DE allowing the material to relax with multiple mechanisms. The constitutive updates at each load increment are obtained by minimizing an objective function formulated using the free energy and electrostatic energy of the elastomer, in addition to the viscous dissipation potential of the dashpots in each Maxwell branch. The model is then used to predict the electromechanical instability (EMI) of DE. The electro-elastic response of the DE is verified with available analytical solutions in the literature and then the material parameters are calibrated using experimental data. The model is integrated with finite element software to perform a variety of simulations on different types of electrically driven actuators under various electromechanical loadings. The electromechanical response of the DE and the critical conditions at which EMI occurs were found to be greatly affected by the viscoelasticity. Our model predicts that under a dead load EMI can be avoided if the DE operates at a high voltage rate. Subjected to constant, ramp and cyclic voltage, our model qualitatively predicts responses similar to the ones obtained from the analytical solutions and experimental data available in the literature. © 2012 Springer-Verlag Berlin Heidelberg.

  3. High electromechanical performance of electroelastomers based on interpenetrating polymer networks

    Science.gov (United States)

    Ha, Soon Mok; Park, Il Seok; Wissler, Michael; Pelrine, Ron; Stanford, Scott; Kim, Kwang J.; Kovacs, Gabor; Pei, Qibing

    2008-03-01

    The electromechanical performance of interpenetrating polymer networks (IPN) in which one elastomer network is under high tension balanced by compression of the second network, were investigated. Uniaxial stress relaxation analysis confirmed significant decrease in viscoelasticity in comparison with 3M VHB films, the primary component network in the IPN films. In dynamic mechanical analysis, the IPN composite showed a higher mechanical efficiency, suggesting delayed relaxation of the acrylic chains in the presence of IPN formation. This improvement was found to be dependant on the contents of poly(TMPTMA). Actuation performance without mechanical prestrain showed that these IPN electroelastomers had demonstrated high elastic strain energy density (3.5 MJ/m 3) and a high electromechanical coupling factor (93.7%). These enhanced electromechanical performances indicate that IPN electroelastomer should be suitable for diverse applications.

  4. Design and development of multi-lane smart electromechanical actuators

    CERN Document Server

    Annaz, Fawaz Yahya

    2014-01-01

    Design and Development of Multi-Lane Smart Electromechanical Actuators presents the design of electromechanical actuators in two types of architectures, namely, Torque Summed Architecture (TSA) and Velocity Summed Architecture, (VSA). It examines them in: * Hardware redundancy, where the architecture is made up of 3 or 4 lanes. * Digital Math Model redundancy, where a more compact two lanes architectures will be presented. The book starts with the very basic concepts and introduces the design process logically so that an understanding of the smart multi-lane systems that drive an aileron

  5. Suppression of electromechanical instability in fiber-reinforced dielectric elastomers

    Directory of Open Access Journals (Sweden)

    Rui Xiao

    2016-03-01

    Full Text Available The electromechanical instability of dielectric elastomers has been a major challenge for the application of this class of active materials. In this work, we demonstrate that dielectric elastomers filled with soft fiber can suppress the electromechanical instability and achieve large deformation. Specifically, we developed a constitutive model to describe the dielectric and mechanical behaviors of fiber-reinforced elastomers. The model was applied to study the influence of stiffness, nonlinearity properties and the distribution of fiber on the instability of dielectric membrane under an electric field. The results show that there exists an optimal fiber distribution condition to achieve the maximum deformation before failure.

  6. Electromechanical actuation for thrust vector control applications

    Science.gov (United States)

    Roth, Mary Ellen

    At present, actuation systems for the Thrust Vector Control (TVC) for launch vehicles are hydraulic systems. The Advanced Launch System (ALS), a joint initiative between NASA and the Air Force, is a launch vehicle that is designed to be cost effective, highly reliable and operationally efficient with a goal of reducing the cost per pound to orbit. As part of this initiative, an electromechanical actuation system is being developed as an attractive alternative to the hydraulic systems used today. NASA-Lewis is developing and demonstrating an Induction Motor Controller Actuation System with a 40 hp peak rating. The controller will integrate 20 kHz resonant link Power Management and Distribution (PMAD) technology and Pulse Population Modulation (PPM) techniques to implement Field Oriented Vector Control (FOVC) of a new advanced induction motor. Through PPM, multiphase variable frequency, variable voltage waveforms can be synthesized from the 20 kHz source. FOVC shows that varying both the voltage and frequency and their ratio (V/F), permits independent control of both torque and speed while operating at maximum efficiency at any point on the torque-speed curve. The driver and the FOVC will be microprocessor controlled. For increased system reliability, a Built-in Test (BITE) capability will be included. This involves introducing testability into the design of a system such that testing is calibrated and exercised during the design, manufacturing, maintenance and prelaunch activities. An actuator will be integrated with the motor controller for performance testing of the EMA TVC system. The design and fabrication of the motor controller is being done by General Dynamics Space Systems Division. The University of Wisconsin-Madison will assist in the design of the advanced induction motor and in the implementation of the FOVC theory. A 75 hp electronically controlled dynamometer will be used to test the motor controller in all four quadrants of operation using flight type

  7. 49 CFR 236.340 - Electromechanical interlocking machine; locking between electrical and mechanical levers.

    Science.gov (United States)

    2010-10-01

    ... Electromechanical interlocking machine; locking between electrical and mechanical levers. In electro-mechanical interlocking machine, locking between electric and mechanical levers shall be maintained so that mechanical... 49 Transportation 4 2010-10-01 2010-10-01 false Electromechanical interlocking machine; locking...

  8. Single-heartbeat electromechanical wave imaging with optimal strain estimation using temporally unequispaced acquisition sequences.

    Science.gov (United States)

    Provost, Jean; Thiébaut, Stéphane; Luo, Jianwen; Konofagou, Elisa E

    2012-02-21

    Electromechanical Wave Imaging (EWI) is a non-invasive, ultrasound-based imaging method capable of mapping the electromechanical wave (EW) in vivo, i.e. the transient deformations occurring in response to the electrical activation of the heart. Optimal imaging frame rates, in terms of the elastographic signal-to-noise ratio, to capture the EW cannot be achieved due to the limitations of conventional imaging sequences, in which the frame rate is low and tied to the imaging parameters. To achieve higher frame rates, EWI is typically performed by combining sectors acquired during separate heartbeats, which are then combined into a single view. However, the frame rates achieved remain potentially sub-optimal and this approach precludes the study of non-periodic arrhythmias. This paper describes a temporally unequispaced acquisition sequence (TUAS) for which a wide range of frame rates are achievable independently of the imaging parameters, while maintaining a full view of the heart at high beam density. TUAS is first used to determine the optimal frame rate for EWI in a paced canine heart in vivo and then to image during ventricular fibrillation. These results indicate how EWI can be optimally performed within a single heartbeat, during free breathing and in real time, for both periodic and non-periodic cardiac events.

  9. Period variations in pulsating X-ray sources. I. Accretion flow parameters and neutron star structure from timing observations

    Energy Technology Data Exchange (ETDEWEB)

    Lamb, F.K.; Pines, D.; Shaham, J.

    1978-09-15

    We show that valuable information about both accretion flows and neutron star structure can be obtained from X-ray timing observations of period variations in pulsating sources. Such variations can result from variations in the accretion flow, or from internal torque variations, associated with oscillations of the fluid core or the unpinning of vortices in the inner crust. We develop a statistical description of torque variations in terms of noise processes, indicate how the applicability of such a description may be tested observationally, and show how it may be used to determine from observation both the properties of accretion flows and the internal structure of neutron stars, including the relative inertial moments of the crust and superfluid neutron core, the crust-core coupling time, and the frequencies of any low-frequency internal collective modes. Particular attention is paid to the physical origin of spin-down episodes; it is shown that usyc episodes may result either from external torque reversals or from internal torque variations.With the aid of the statistical description, the response of the star to torque fluctuations is calculated for three stellar models: (i) a completely rigid star; (ii) a two-component star; and (iii) a two-component star with a finite-frequency internal mode, such as the Tkachenko mode of a rotating neutron superfluid. Our calculations show that fluctuating torques could account for the period the period variations and spin-down episodes observed in Her X-1 and Cen X-3, including the large spin-down event observed in the latter source during 1972 September-October. The torque noise strengths inferred from current timing observations using the simple two-component models are shown to be consistent with those to be expected from fluctuations in accretion flows onto magnetic neutron stars.

  10. Electromechanical and robot-assisted arm training for improving arm function and activities of daily living after stroke.

    Science.gov (United States)

    Mehrholz, Jan; Platz, Thomas; Kugler, Joachim; Pohl, Marcus

    2008-10-08

    did not increase the risk of patients to drop out (RD) (fixed-effect model) = 0.01; 95% CI -0.05 to 0.06; P = 0.77; I(2 )= 0.0%) and adverse events were rare. Patients who receive electromechanical and robot-assisted arm training after stroke are not more likely to improve their activities of daily living, but arm motor function and strength of the paretic arm may improve. However, the results must be interpreted with caution because there were variations between the trials in the duration, amount of training and type of treatment, and in the patient characteristics.

  11. Predictability study of Kuroshio path variation:Effects of initial error and model parameter errors on the prediction

    Science.gov (United States)

    Wang, Q.; Mu, M.; Dijkstra, H. A.

    2012-04-01

    Conditional nonlinear optimal parameter perturbation (CNOP-P) method is used to investigate the effects of errors in model parameters on the prediction of the transition to the Kuroshio large meander (KLM) state in a barotropic shallow-water model. Because of their relatively large uncertainties, three model parameters were considered: the interfacial friction coefficient, the wind-stress amplitude, and the lateral friction coefficient. We determined the CNOP-Ps optimized for each of these three parameters independently, and we optimized all three parameters simultaneously using the Spectral Projected Gradient 2 (SPG2) algorithm. Similarly, the impacts caused by errors in initial conditions were examined using the conditional nonlinear optimal initial perturbation (CNOP-I) method. Both the CNOP-I and CNOP-Ps can result in significant prediction errors of the KLM over a lead time of 240 days. But the prediction error caused by CNOP-I is greater than that caused by CNOP-P. The results of this study indicate not only that initial errors have greater effects on the prediction of the KLM than errors in model parameters but also that the latter cannot be ignored. Hence, to enhance the forecast skill of the KLM in this model, the initial conditions should first be improved, the model parameters should use the best possible estimates.

  12. FEM Analysis of a New Electromechanical Converter with Rolling Rotor and Axial Air-Gap

    Directory of Open Access Journals (Sweden)

    UNGUREANU, C.

    2015-11-01

    Full Text Available The paper presents the modeling of a new type of electromechanical converter with rolling rotor (ECRR in order to obtain an optimisation at functional level. The ECRR prototype comprises a stator composed of twelve magnetic poles and a disk-shaped rolling rotor made of ferromagnetic material, without windings. Each magnetic pole is made of an E-shaped magnetic system and a winding placed on its central column. The electromechanical converter with rolling rotor is analyzed through a magnetic field study with Flux2D software in magnetostatic application. The field study examines the influence of the rotor thickness, axial air-gap size and current density on the magnetic attraction force that changes the position of the disk-shaped rolling rotor. Also, it is analyzed the variation of the magnetic attraction force for different inclination angles of the rolling rotor. The main advantage of the ECRR is represented by a low rotational speed without using mechanical gearboxes. The ECRR prototype can be used in photovoltaic panels tracking systems.

  13. Distributed electromechanical actuation system design for a morphing trailing edge wing

    Science.gov (United States)

    Dimino, I.; Diodati, G.; Concilio, A.; Volovick, A.; Zivan, L.

    2016-04-01

    Next-generation flight control actuation technology will be based on "more electric" concepts to ensure benefits in terms of efficiency, weight and maintenance. This paper is concerned with the design of an un-shafted distributed servo-electromechanical actuation system, suited for morphing trailing edge wings of large commercial aircraft. It aims at producing small wing camber variations in the range between -5° and +5° in cruise, to enable aerodynamic efficiency improvements. The deployment kinematics is based on multiple "direct-drive" actuation, each made of light-weight compact lever mechanisms, rigidly connected to compliant ribs and sustained by load-bearing motors. Navier-Stokes computations are performed to estimate the pressure distribution over the interested wing region and the resulting hinge moments. These transfer to the primary structure via the driving mechanism. An electro-mechanical Matlab/Simulink model of the distributed actuation architecture is developed and used as a design tool, to preliminary evaluate the complete system performance. Implementing a multi-shaft strategy, each actuator is sized for the torque acting on the respective adaptive rib, following the effect of both the aerodynamic pressure and the morphing skin stiffness. Elastic trailing edge rotations and power needs are evaluated in operative conditions. Focus is finally given to the key challenges of the proposed concept: targeting quantifiable performance improvements while being compliant to the demanding requirements in terms of reliability and safety.

  14. Temperature dependence of electromechanical properties of PLZT x ...

    Indian Academy of Sciences (India)

    Administrator

    the temperature dependence of electromechanical proper- ties of PLZT. It has been observed that the compositions of PLZT ceramics with Zr/Ti 57/43 show enhanced piezoelectric response at room temperature and can be used in low power transducer devices (Shukla et al 2004). Keeping the device application in view, ...

  15. Failure mechanisms and electromechanical coupling in semiconducting nanowires

    Directory of Open Access Journals (Sweden)

    Peng B.

    2010-06-01

    Full Text Available One dimensional nanostructures, like nanowires and nanotubes, are increasingly being researched for the development of next generation devices like logic gates, transistors, and solar cells. In particular, semiconducting nanowires with a nonsymmetric wurtzitic crystal structure, such as zinc oxide (ZnO and gallium nitride (GaN, have drawn immense research interests due to their electromechanical coupling. The designing of the future nanowire-based devices requires component-level characterization of individual nanowires. In this paper, we present a unique experimental set-up to characterize the mechanical and electromechanical behaviour of individual nanowires. Using this set-up and complementary atomistic simulations, mechanical properties of ZnO nanowires and electromechanical properties of GaN nanowires were investigated. In ZnO nanowires, elastic modulus was found to depend on nanowire diameter decreasing from 190 GPa to 140 GPa as the wire diameter increased from 5 nm to 80 nm. Inconsistent failure mechanisms were observed in ZnO nanowires. Experiments revealed a brittle fracture, whereas simulations using a pairwise potential predicted a phase transformation prior to failure. This inconsistency is addressed in detail from an experimental as well as computational perspective. Lastly, in addition to mechanical properties, preliminary results on the electromechanical properties of gallium nitride nanowires are also reported. Initial investigations reveal that the piezoresistive and piezoelectric behaviour of nanowires is different from bulk gallium nitride.

  16. a comparison of performances of electronic and electromechanical

    African Journals Online (AJOL)

    NIJOTECH

    ABSTRACT. The Ferraris (electromechanical) energy meter has had predominance in the metering of energy consumption using the alternating current supply system. Electronic energy meters are gaining popularity because of the possibility of remote reading and controllable non uniform rate of billing. In this work, an.

  17. A system look at electromechanical actuation for primary flight control

    NARCIS (Netherlands)

    Lomonova, E.A.

    1997-01-01

    An overview is presented of the emergence of the ALL Electric flight control system (FCS) or power-by-wire (PBW) concept. The concept of fly-by-power refers to the actuator using electrical rather than hydraulic power. The development of the primary flight control Electromechanical Actuators (EMAs)

  18. Space vehicle electromechanical system and helical antenna winding fixture

    Energy Technology Data Exchange (ETDEWEB)

    Judd, Stephen; Dallmann, Nicholas; Guenther, David; Enemark, Donald; Seitz, Daniel; Martinez, John; Storms, Steven

    2017-12-26

    A space vehicle electromechanical system may employ an architecture that enables convenient and practical testing, reset, and retesting of solar panel and antenna deployment on the ground. A helical antenna winding fixture may facilitate winding and binding of the helical antenna.

  19. A Comparison of Performances of Electronic and Electromechanical ...

    African Journals Online (AJOL)

    The Ferraris (electromechanical) energy meter has had predominance in the metering of energy consumption using the alternating current supply system. Electronic energy meters are gaining popularity because of the possibility of remote reading and controllable non uniform rate of billing. In this work, an electronic energy ...

  20. Variation of Ultrasonic Parameters With Microstructure and Material Properties of Trabecular Bone: A 3D Model Simulation

    National Research Council Canada - National Science Library

    Haïat, Guillaume; Padilla, Frédéric; Peyrin, Françoise; Laugier, Pascal

    2007-01-01

    .... We studied the sensitivity of quantitative ultrasound (QUS) to bone volume fraction by examining QUS parameters at different stages of trabecular thinning or thickening using an iterative dedicated algorithm...

  1. Kinetic parameters and structural variations in Cu-Al-Mn and Cu-Al-Mn-Mg shape memory alloys

    Science.gov (United States)

    Canbay, Canan Aksu

    2017-02-01

    In this work polycrystalline Cu-Al-Mn and Cu-Al-Mn-Mg SMAs were fabricated by arc melting. The thermal analysis was made to determine the characteristic transformation temperatures of the samples and kinetic parameters. Also the effect of Mg on transformation temperatures and kinetic parameters detected. The structural analysis was made to designate the diffraction planes of martensite phase at room temperature and this was supported by optical measurement observations.

  2. Genetic Variation in One-Carbon Metabolism and Changes in Metabolic Parameters in First-Episode Schizophrenia Patients

    OpenAIRE

    Misiak, B?a?ej; ?aczma?ski, ?ukasz; S?oka, Natalia Kinga; Szmida, El?bieta; ?l?zak, Ryszard; Piotrowski, Patryk; Kiejna, Andrzej; Frydecka, Dorota

    2016-01-01

    Abstract Background: In this study, we aimed to investigate the effects of polymorphisms in genes encoding 1-carbon metabolism enzymes on differential development of metabolic parameters during 12 weeks of treatment with second-generation antipsychotics in first-episode schizophrenia patients. Methods: The following polymorphisms in 1-carbon metabolism genes were genotyped: MTHFR (C677T and A1298C), MTHFD1 (G1958A), MTRR (A66G), and BHMT (G742A). A broad panel of metabolic parameters includin...

  3. Statistical variations of source parameters in inter- and intraplate earthquakes in Chile and their correlations with the slab properties.

    Science.gov (United States)

    Derode, B.

    2015-12-01

    Understanding the rupture processes of intermediate-depth earthquakes in active subduction zones and their dependence to inherited geophysical parameters, such as the maturity and orientation of pre-existing faults, is still of prime interest. Unfortunately, quantitative values describing the nucleation and propagation processes at depths are rare, and the earthquake source parameters determined from global databases or far-field measurements are often very heterogeneous, especially for the smallest and deepest earthquakes. In order to leveling this problem and discriminate specific characteristics of the intermediate-depth earthquakes in Chile (IDEQ-Chile), we conducted high precision measurements using local and regional waveforms data obtained from broadband and strong-motions stations of IPOC network in northern Chile. A strict and rigorous methodology was used to reduce the scattering of the source parameter estimation usually observed. With this high-quality database, we examined the source characteristics of a few hundreds of intra-slab intermediate depth-earthquakes, with depth varying from 40 km to 300 km. For the effective comparison of the source parameters, we studied with the same approach a hundred of interplate earthquakes located along the same latitude-dependent zone of the subducted slab. Based on static and cinematic considerations, we compared these source parameters with macroscopic geophysical parameters such as the stress regime, the coupling degree or the style of faulting, in order to show the possible correlations between them. Interestingly, we observed three major depth-dependent zones corresponding to three different sets of static and dynamic source parameters. We show that there are some evident differences between these distinct Chilean zones, although the apparent quasi-constant velocity and age of the subducted Nazca plate along Chile. We discuss how some of the various proposed sources mechanisms, explaining the earthquakes

  4. To the Problem of Electromechanical Interaction in Elevators with Controlled Electric Drive and Fuzzy Speed Controller

    Directory of Open Access Journals (Sweden)

    A. S. Koval

    2010-01-01

    Full Text Available The paper considers problems concerning electromechanical interaction in elevators with an adjustable asynchronous electric drive equipped with the vector control systems under direct torque control and direct torque control with pulse-width modulator. A mathematical description of electromechanical elevator system with due account of nonlinearity of the worm gear is given in the paper. The paper presents a simplified circuit design of a control system with a fuzzy speed controller. It has been established that the factor of electromechanical interaction in electromechanical system with the adjustable asynchronous electric drive and an fuzzy speed controller is within the range which corresponds to existence of the essential electromechanical interaction.

  5. Evaluation of significant sources influencing the variation of physico-chemical parameters in Port Blair Bay, South Andaman, India by using multivariate statistics.

    Science.gov (United States)

    Sahu, Biraja Kumar; Begum, Mehmuna; Khadanga, M K; Jha, Dilip Kr; Vinithkumar, N V; Kirubagaran, R

    2013-01-15

    Port Blair is the capital city of Andaman & Nicobar Islands, the union territory of India. More than 50% of the population of these islands lives around Port Blair Bay. Therefore the anthropogenic effects in the bay water were studied for monitoring purpose from seven stations. Physico-chemical parameters of seawater were analyzed in samples collected once in every 3 months for 2 years from seven sampling stations located in Port Blair Bay, South Andaman Island to evaluate the spatial and tidal variation. Cluster analysis and factor analysis were applied to the experimental data in an attempt to understand the sources of variation of physico-chemical parameters. In cluster analysis, the stations Junglighat Bay and Phoenix Bay having high anthropogenic influence formed a separate group. The factors obtained from factor analysis indicated that the parameters responsible for physico-chemical variations are mainly related to land run-off, sewage outfall and tidal flow. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  6. Early ontogeny shows the same interspecific variation as natural history parameters in the crested newt (Triturus cristatus superspecies) (Caudata, Salamandridae)

    NARCIS (Netherlands)

    Cvijanović, M.; Ivanović, A.; Kolarov, N.T.; Džukić, G.; Kalezić, M.L.

    2009-01-01

    When the phenotypic divergence within a monophyletic group is characterised by parallel variation of different phenotypic traits, it is very likely that the environment through constraints and/or selection has affected the developmental pathways simultaneously. Such patterns of phenotypic divergence

  7. GENOTYPIC VARIATION IN CHLOROPHYLL FLUORESCENCE PARAMETERS, PHOTOSYNTHESIS AND GROWTH OF TOMATO GROWN AT LOW-TEMPERATURE AND LOW IRRADIANCE

    NARCIS (Netherlands)

    JANSSEN, LHJ; VANOEVEREN, JC; VANHASSELT, PR; KUIPER, PJC

    1995-01-01

    The genetic variation in low temperature sensitivity of eight tomato genotypes grown at suboptimal temperature (19 degrees C) and at low irradiance (140 mu mol m(-2) s(-1)) was assessed at the plant, chloroplast and thylakoid membrane levels. Temperature effects on the thylakoid membrane were

  8. Effects of variation in coagulation and photochemistry parameters on the particle size distributions in the Venus clouds

    Science.gov (United States)

    McGouldrick, Kevin

    2017-12-01

    This paper explores the effects that variation in the coalescence efficiency of the Venus cloud particles can have on the structure of the Venus cloud. It is motivated by the acknowledgment of uncertainties in the measured parameters—and the assumptions made to account for them—that define our present knowledge of the particle characteristics. Specifically, we explore the consequence of allowing the coalescence efficiency of supercooled sulfuric acid in the upper clouds to tend to zero. This produces a cloud that occasionally exhibits an enhancement of small particles at altitude (similar to the upper hazes observed by Pioneer Venus and subsequently shown to be somewhat transient). This simulated cloud occasionally exhibits a rapid growth of particle size near cloud base, exhibiting characteristics similar to those seen in the controversial Mode 3 particles. These results demonstrate that a subset of the variations observed as near-infrared opacity variations in the lower and middle clouds of Venus can be explained by microphysical, in addition to dynamical, variations. Furthermore, the existence of a population of particles exhibiting less efficient coalescence efficiencies would support the likelihood of conditions suitable for charge exchange, hence lightning, in the Venus clouds. We recommend future laboratory studies on the coalescence properties of sulfuric acid under the range of conditions experienced in the Venus clouds. We also recommend future in situ measurements to better characterize the properties of the cloud particles themselves, especially composition and particle habits (shapes).[Figure not available: see fulltext.

  9. Underestimation of Effect of Thyroid Function Parameters on Morbidity and Mortality due to Intra-Individual Variation.

    NARCIS (Netherlands)

    Ven, A.C. van de; Netea-Maier, R.T.; Medici, M.; Sweep, F.C.; Ross, H.A.; Hofman, A.; Graaf, J. de; Kiemeney, L.A.L.M.; Hermus, A.R.M.M.; Peeters, R.P.; Visser, T.J.; Heijer, M. den

    2011-01-01

    Introduction: Thyroid dysfunction is associated with several diseases and mortality. Due to the within-individual variation of TSH and free T(4) (FT(4)) levels, the association between thyroid function and disease or mortality rates might be underestimated in studies based on one single measurement

  10. Underestimation of effect of thyroid function parameters on morbidity and mortality due to intra-individual variation

    NARCIS (Netherlands)

    A.C. van de Ven (Annenienke); R.T. Netea-Maier (Romana ); M. Medici (Marco); F.C. Sweep (Fred); H.A. Ross (Alec); A. Hofman (Albert); J. de Graaf (Jacqueline); L.A.L.M. Kiemeney (Bart); A.R.M.M. Hermus (Ad); R.P. Peeters (Robin); T.J. Visser (Theo); M. den Heijer (Martin)

    2011-01-01

    textabstractIntroduction: Thyroid dysfunction is associated with several diseases and mortality. Due to the within-individual variation of TSH and free T 4 (FT 4) levels, the association between thyroid function and disease or mortality rates might be underestimated in studies based on one single

  11. The Sensitivity Analysis of Parameters of Urban Runoff Models due to Variations of Basin Characteristics (II) : Model Calibration and Application

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Kyu Woo [Dongeui University, Pusan (Korea); Heo, Jun Haeng [Yonsei University, Seoul (Korea)

    1998-06-30

    In this study, ILLUDAS and SWMM were applied for Dongsucheon basin, Inchon and Test basin, Chongju. The main parameters(II, IA, IS, SI, SR, SS) which are included in those of each model depending on runoff results were determined, and sensitivity ratios were estimated in order to evaluate and compare the characteristics of each model. Total runoff ratio for almost parameters turned out to have a linear relation to the rainfall durations and the scale of basin area but have nothing to do with rainfall distributions. Sensitivity ratios turned out to have a linear relation for the infiltration and soil parameters of ILLUDAS as well as all parameters of SWMM. Runoff sensitivity ratios for almost parameters were smaller than 1.0 because the impacts of total runoff were bigger than those of peak runoff. And runoff sensitivity ratio was equal to 1.0 for the roughness coefficient of SWMM. Total runoff ratio, peak runoff ratio and runoff sensitivity ratio for the selected parameters of those models were presented as the tables and figures according to the scale of basin area, rainfall durations such as 60, 120, and 180 minutes and Huff's fourth quartiles rainfall distributions. (author). 16 refs., 8 tabs., 20 figs.

  12. Combining wood anatomy and stable isotope variations in a 600-year multi-parameter climate reconstruction from Corsican black pine

    Science.gov (United States)

    Szymczak, Sonja; Hetzer, Timo; Bräuning, Achim; Joachimski, Michael M.; Leuschner, Hanns-Hubert; Kuhlemann, Joachim

    2014-10-01

    We present a new multi-parameter dataset from Corsican black pine growing on the island of Corsica in the Western Mediterranean basin covering the period AD 1410-2008. Wood parameters measured include tree-ring width, latewood width, earlywood width, cell lumen area, cell width, cell wall thickness, modelled wood density, as well as stable carbon and oxygen isotopes. We evaluated the relationships between different parameters and determined the value of the dataset for climate reconstructions. Correlation analyses revealed that carbon isotope ratios are influenced by cell parameters determining cell size, whereas oxygen isotope ratios are influenced by cell parameters determining the amount of transportable water in the xylem. A summer (June to August) precipitation reconstruction dating back to AD 1185 was established based on tree-ring width. No long-term trends or pronounced periods with extreme high/low precipitation are recorded in our reconstruction, indicating relatively stable moisture conditions over the entire time period. By comparing the precipitation reconstruction with a summer temperature reconstruction derived from the carbon isotope chronologies, we identified summers with extreme climate conditions, i.e. warm-dry, warm-wet, cold-dry and cold-wet. Extreme climate conditions during summer months were found to influence cell parameter characteristics. Cold-wet summers promote the production of broad latewood composed of wide and thin-walled tracheids, while warm-wet summers promote the production of latewood with small thick-walled cells. The presented dataset emphasizes the potential of multi-parameter wood analysis from one tree species over long time scales.

  13. Models of field-aligned currents needful to simulate the substorm variations of the electric field and other parameters observed by EISCAT

    Directory of Open Access Journals (Sweden)

    M. A. Volkov

    1996-12-01

    Full Text Available We have used the global numerical model of the coupled ionosphere-thermosphere-protonosphere system to simulate the electric-field, ion- and electron-temperature and -concentration variations observed by EISCAT during the substorm event of 25 March 1987. In our previous studies we adopted the model input data for field-aligned currents and precipitating electron fluxes to obtain an agreement between observed and modelled ionospheric variations. Now, we have calculated the field-aligned currents needful to simulate the substrom variations of the electric field and other parameters observed by EISCAT. The calculations of the field-aligned currents have been performed by means of numerical integration of the time-dependent continuity equation for the cold magnetospheric electrons. This equation was added to the system of the modelling equations including the equation for the electric-field potential to be solved jointly. In this case the inputs of the model are the spatial and time variations of the electric-field potential at the polar-cap boundaries and those of the cold magnetospheric electron concentration which have been adopted to obtain the agreement between the observed and modelled ionospheric variations for the substorm event of 25 March 1987. By this means it has been found that during the active phase of the substorm the current wedge is formed. It is connected with the region of the decreased cold magnetospheric electron content travelling westwards with a velocity of about 1 km s–1 at ionospheric levels.

  14. Study on the effect of hydrogen addition on the variation of plasma parameters of argon-oxygen magnetron glow discharge for synthesis of TiO2 films

    Directory of Open Access Journals (Sweden)

    Partha Saikia

    2016-04-01

    Full Text Available We report the effect of hydrogen addition on plasma parameters of argon-oxygen magnetron glow discharge plasma in the synthesis of H-doped TiO2 films. The parameters of the hydrogen-added Ar/O2 plasma influence the properties and the structural phases of the deposited TiO2 film. Therefore, the variation of plasma parameters such as electron temperature (Te, electron density (ne, ion density (ni, degree of ionization of Ar and degree of dissociation of H2 as a function of hydrogen content in the discharge is studied. Langmuir probe and Optical emission spectroscopy are used to characterize the plasma. On the basis of the different reactions in the gas phase of the magnetron discharge, the variation of plasma parameters and sputtering rate are explained. It is observed that the electron and heavy ion density decline with gradual addition of hydrogen in the discharge. Hydrogen addition significantly changes the degree of ionization of Ar which influences the structural phases of the TiO2 film.

  15. Variation of Supergranule Parameters with Solar Cycles: Results from Century-long Kodaikanal Digitized Ca ii K Data

    Energy Technology Data Exchange (ETDEWEB)

    Chatterjee, Subhamoy; Mandal, Sudip; Banerjee, Dipankar, E-mail: dipu@iiap.res.in [Indian Institute of Astrophysics, Koramangala, Bangalore 560034 (India)

    2017-06-01

    The Ca ii K spectroheliograms spanning over a century (1907–2007) from Kodaikanal Solar Observatory, India, have recently been digitized and calibrated. Applying a fully automated algorithm (which includes contrast enhancement and the “Watershed method”) to these data, we have identified the supergranules and calculated the associated parameters, such as scale, circularity, and fractal dimension. We have segregated the quiet and active regions and obtained the supergranule parameters separately for these two domains. In this way, we have isolated the effect of large-scale and small-scale magnetic fields on these structures and find a significantly different behavior of the supergranule parameters over solar cycles. These differences indicate intrinsic changes in the physical mechanism behind the generation and evolution of supergranules in the presence of small-scale and large-scale magnetic fields. This also highlights the need for further studies using solar dynamo theory along with magneto-convection models.

  16. Phosphatidylserine exposure on stored red blood cells as a parameter for donor-dependent variation in product quality

    OpenAIRE

    Dinkla, Sip; Peppelman, Malou; van der Raadt, Jori; Atsma, Femke; Novotný, Vĕra M.J.; van Kraaij, Marian G.J.; Joosten, Irma; Bosman, Giel J.C.G.M.

    2014-01-01

    BACKGROUND: Exposure of phosphatidylserine on the outside of red blood cells contributes to recognition and removal of old and damaged cells. The fraction of phosphatidylserine-exposing red blood cells varies between donors, and increases in red blood cell concentrates during storage. The susceptibility of red blood cells to stress-induced phosphatidylserine exposure increases with storage. Phosphatidylserine exposure may, therefore, constitute a link between donor variation and the quality o...

  17. Lattice variation and thermal parameters of NixMg1–xSO4⋅7H2O ...

    Indian Academy of Sciences (India)

    Unknown

    unit cell parameters for magnesium sulphate heptahydrate,. MgSO4⋅7H2O .... a given type of atom. This disorder enhances the Debye–. Waller factor and also the amplitude of vibration. Hence the observed Debye–Waller factor for mixed crystal is written as ... measured and m the mean atomic mass of crystal. The function ...

  18. Elucidation of seasonal variations of physicochemical and biological parameters with statistical analysis methods in Puducherry coastal waters.

    Science.gov (United States)

    Bharathi, M D; Sivaji Patra; Sundaramoorthy, S; Madeswaran, P; Sundaramanickam, A

    2017-09-15

    The present investigation aimed to study the effect of monsoonal and anthropogenic influences on the water quality parameters of Puducherry coastal waters. Surface water sampling was performed at three fixed stations in four distinct seasons during 2011. Physical water quality parameters such as salinity and TSM showed strong seasonal and spatial variability. Evaporation and monsoonal runoff seem to be the major controlling forces for these parameters in the coastal waters. Seasonal distribution of the parameters showed a random pattern for nitrate and a well-defined pattern for silicate. Chl-a was minimum during monsoon when high TSM was encountered in the system. Moreover, factors that regulated the phytoplankton biomass varied with seasons. Moreover, TSM was strongly correlated with silicate. The relationship between Chl-a and nutrients were more consistent throughout the year, and much weaker correlations were noticed between Chl-a and TSM. Cluster analysis depicted the existence of a marked seasonal heterogeneity. Copyright © 2017. Published by Elsevier Ltd.

  19. Increase in winter haze over eastern China in recent decades: Roles of variations in meteorological parameters and anthropogenic emissions: INCREASE IN WINTER HAZE IN EASTERN CHINA

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yang [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Liao, Hong [School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing China; Joint International Research Laboratory of Climate and Environment Change, Nanjing University of Information Science and Technology, Nanjing China; Lou, Sijia [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA

    2016-11-05

    The increase in winter haze over eastern China in recent decades due to variations in meteorological parameters and anthropogenic emissions was quantified using observed atmospheric visibility from the National Climatic Data Center Global Summary of Day database for 1980–2014 and simulated PM2.5 concentrations for 1985–2005 from the Goddard Earth Observing System (GEOS) chemical transport model (GEOS-Chem). Observed winter haze days averaged over eastern China (105–122.5°E, 20–45°N) increased from 21 d in 1980 to 42 d in 2014, and from 22 to 30 d between 1985 and 2005. The GEOS-Chem model captured the increasing trend of winter PM2.5 concentrations for 1985–2005, with concentrations averaged over eastern China increasing from 16.1 μg m-3 in 1985 to 38.4 μg m-3 in 2005. Considering variations in both anthropogenic emissions and meteorological parameters, the model simulated an increase in winter surface-layer PM2.5 concentrations of 10.5 (±6.2) μg m-3 decade-1 over eastern China. The increasing trend was only 1.8 (±1.5) μg m-3 decade-1 when variations in meteorological parameters alone were considered. Among the meteorological parameters, the weakening of winds by -0.09 m s-1 decade-1 over 1985–2005 was found to be the dominant factor leading to the decadal increase in winter aerosol concentrations and haze days over eastern China during recent decades.

  20. Can the monitoring of animal welfare parameters predict pork meat quality variation through the supply chain (from farm to slaughter)?

    Science.gov (United States)

    Rocha, L M; Velarde, A; Dalmau, A; Saucier, L; Faucitano, L

    2016-01-01

    The objective of this study was to assess the relationship between the animal welfare conditions evaluated through the supply chain and pork quality variation. A total of 4,680 pigs from 12 farms-5 animal welfare improved raising system (AWIRS) and 7 conventional raising system (CON) farms-were assessed from farm to slaughter through a comprehensive audit protocol merging the European Welfare Quality, the Canadian Animal Care Assessment, and American Meat Institute audit guide criteria. At the abattoir, a subsample of 1,440 pigs (120 pigs/farm) was randomly chosen out of 24 loads (2 farms per wk) transported by 2 drivers (driver A and driver B) for the assessment of stunning effectiveness, carcass bruises, blood lactate levels, and meat quality traits. Meat quality was assessed in the longissimus lumborum (LL) muscle 24 h postmortem by measuring ultimate pH (pHu), color (L*, a*, and b*), and drip loss. Data were analyzed by the MIXED, GLIMMIX, and NAPAR1WAY procedures of SAS. Spearman correlations were calculated to determine the relationship between audit scores and meat quality traits. Better animal welfare conditions, as showed by greater final scores for good housing (GHo; = 0.001) and good health ( = 0.006) principles, were recorded at AWIRS farms. Pigs from AWIRS farms handled by driver B displayed a greater percentage of turning back ( = 0.01) and slips ( animal welfare audit protocols are important sources of variation in the behavioral response of pigs to preslaughter handling and may affect pork quality variation. However, the different live weight between CON and AWIRS pigs may have biased the meat quality results in this study.

  1. Temporal and vertical variations in phythoplankton community structure and its relation to some morphometric parameters of four Colombian reservoirs Temporal and vertical variations in phythoplankton community structure and its relation to some morphometric parameters of four Colombian reservoirs

    Directory of Open Access Journals (Sweden)

    Ramírez R. John J.

    2000-07-01

    Full Text Available Phytoplankton samples were taken at three depths within the photie zone of eaeh of four reservoirs, Punehiná, Las Playas, El Peñol and San Lorenzo loeated in Antioquia department, Colombia. A total of 77 taxa were identified in the four reservoirs. Diatoms were not included. In all reservoirs, Chlorophyta was the dominant group. Botryococcus braunii was the dominant species at Punchiná, Las Playas and El Peñol reservoirs; Cosmarium sp. was the dominant at San Lorenzo. Temporal variation in phytoplankton showed two peaks of abundance, apparently related to precipitation. Taxonomic composition among samples from the same reservoir showed little variation. Community structure at different depths showed significant differences only at San Lorenzo reservoir. The inverse of β-diversity showed small values indicating high similarity among the reservoirs. Diversitv showed no significant assoeiation with any morphometric factor evaluated (area, retention time, altitude and age.Se efectuaron muestreos de fitoplaneton en tres profundidades de la zona fótica de los embalses Punchiná, Las Playas, El Peñol y San Lorenzo, localizados en el departamento de Antioquia, Colombia. Se identificaron un total de 77 taxones en los cuatro embalses. Las diatomeas no fueron incluídas. En todos los casos las Cholorophyta fueron el grupo dominante. Botryococcus braunii fue el taxón de mayor densidad en los embalses Punchiná, Las Playas y El Peñol; y Cosmarium sp. en el embalse San Lorenzo. La comunidad fitoplanctónica mostró dos picos de abundancia aparentemente relacionados con la precipitación. En cada embalse, la composición de taxones entre muestreos varió poco. La estructura de la comunidad a diferentes profundidades mostró diferencias significativas únicamente en el embalse San Lorenzo. El inverso de la β-diversidad presentó valores bajos que muestran la alta similaridad entre embalses. La diversidad no mostró asociación significativa con

  2. Development of an Electromechanical Grade to Assess Human Knee Articular Cartilage Quality.

    Science.gov (United States)

    Sim, Sotcheadt; Hadjab, Insaf; Garon, Martin; Quenneville, Eric; Lavigne, Patrick; Buschmann, Michael D

    2017-10-01

    Quantitative assessments of articular cartilage function are needed to aid clinical decision making. Our objectives were to develop a new electromechanical grade to assess quantitatively cartilage quality and test its reliability. Electromechanical properties were measured using a hand-held electromechanical probe on 200 human articular surfaces from cadaveric donors and osteoarthritic patients. These data were used to create a reference electromechanical property database and to compare with visual arthroscopic International Cartilage Repair Society (ICRS) grading of cartilage degradation. The effect of patient-specific and location-specific characteristics on electromechanical properties was investigated to construct a continuous and quantitative electromechanical grade analogous to ICRS grade. The reliability of this novel grade was assessed by comparing it with ICRS grades on 37 human articular surfaces. Electromechanical properties were not affected by patient-specific characteristics for each ICRS grade, but were significantly different across the articular surface. Electromechanical properties varied linearly with ICRS grade, leading to a simple linear transformation from one scale to the other. The electromechanical grade correlated strongly with ICRS grade (r = 0.92, p < 0.0001). Additionally, the electromechanical grade detected lesions that were not found visually. This novel grade can assist the surgeon in assessing human knee cartilage by providing a quantitative and reliable grading system.

  3. Single-Heartbeat Electromechanical Wave Imaging with Optimal Strain Estimation Using Temporally-Unequispaced Acquisition Sequences

    Science.gov (United States)

    Provost, Jean; Thiébaut, Stéphane; Luo, Jianwen; Konofagou, Elisa E.

    2014-01-01

    Electromechanical Wave Imaging (EWI) is a non-invasive, ultrasound-based imaging method capable of mapping the electromechanical wave (EW) in vivo, i.e., the transient deformations occurring in response to the electrical activation of the heart. Achieving the optimal imaging frame rates, in terms of the elastographic signal-to-noise ratio, to capture the EW in a full-view of the heart poses a technical challenge due to the limitations of conventional imaging sequences, in which the frame rate is low and tied to the imaging parameters. To achieve higher frame rates, EWI is typically performed in multiple small regions of interest acquired over separate heartbeats, which are then combined into a single view. However, the reliance on multiple heartbeats has previously precluded the method from its application in non-periodic arrhythmias such as fibrillation. Moreover, the frame rates achieved remain sub-optimal, because they are determined by the imaging parameters rather than being optimized to image the EW. In this paper, we develop a temporally-unequispaced acquisition sequence (TUAS) for which a wide range of frame rates are achievable independently of the imaging parameters, while maintaining a full view of the heart at high beam density. TUAS is first used to determine the optimal frame rate for EWI in a paced canine heart in vivo. The feasibility of performing single-heartbeat EWI during ventricular fibrillation is then demonstrated. These results indicate that EWI can be performed optimally, within a single heartbeat, during free breathing, and implemented in real time for periodic and non-periodic cardiac events. PMID:22297208

  4. Deriving daily and seasonal variations in meteorological gravity wave parameters from a tropical infrasound station and comparisons with lightning strike data form ATDnet and TRMM LIS.

    Science.gov (United States)

    Marlton, Graeme; Charlton-Perez, Andrew; Harrison, Giles

    2017-04-01

    A wealth of work has shown that meteorological gravity wave parameters can be derived from both satellite data and weather balloons. Satellite data has good temporal and spatial coverage but can only probe the lower stratosphere and mesosphere. Radiosonde wind and temperature profiles can also be used to infer gravity wave information in the upper troposphere and lower stratosphere. Both methods have been used to investigate seasonal variations in gravity wave parameters at these heights. However, these methods cannot be used to infer gravity wave parameters near the surface. One method to detect atmospheric gravity waves at the surface is by using an infrasound array. Infrasound arrays consist of several microbarometers which are spaced kilometres apart. As the wave passes over the array subtle pressure perturbations are subsequently detected at each microbarometer. The temporal differences in each microbarometer's time series allow a gravity wave's velocity, back azimuth, ground based frequency and amplitude to be calculated using the progressive multichannel correlation method. In order to calculate further meteorological values such as wave number, velocity perturbations and hence find the momentum flux for each gravity wave, data from meteorological station in close proximity to the array need to be combined with the infrasound data, which is explored here. Gravity wave parameters calculated from infra sound data combined with meteorological data over several years will be shown for a station (IS17) in the Ivory Coast. Blanc et al 2010 showed an annual variation in gravity wave back azimuth due to the shifting of thunderstorms associated with the ITCZ. A spectral analysis of all gravity wave parameters has revealed daily and seasonal variations, which are further explored. To further understand the seasonal variations observed data from the Tropical Rainfall Measurement Mission (TRMM) rainfall estimate and TRMM LIS lightning data are used to relate how the

  5. Interhuman transmission as a potential key parameter for geographical variation in the prevalence of Pneumocystis jirovecii dihydropteroate synthase mutations.

    Science.gov (United States)

    Hauser, Philippe M; Nahimana, Aimable; Taffe, Patrick; Weber, Rainer; Francioli, Patrick; Bille, Jacques; Rabodonirina, Meja

    2010-08-15

    Pneumocystis jirovecii dihydropteroate synthase (DHPS) mutations are associated with failure of prophylaxis with sulfa drugs. This retrospective study sought to better understand the geographical variation in the prevalence of these mutations. DHPS polymorphisms in 394 clinical specimens from immunosuppressed patients who received a diagnosis of P. jirovecii pneumonia and who were hospitalized in 3 European cities were examined using polymerase chain reaction (PCR) single-strand conformation polymorphism. Demographic and clinical characteristics were obtained from patients' medical charts. Of the 394 patients, 79 (20%) were infected with a P. jirovecii strain harboring one or both of the previously reported DHPS mutations. The prevalence of DHPS mutations was significantly higher in Lyon than in Switzerland (33.0% vs 7.5%; P DHPS genotype was significantly higher in Lyon than in Switzerland (29.7% vs 3.0%; P DHPS mutations.

  6. Thermoplastic Dielectric Elastomer of Triblock Copolymer with High Electromechanical Performance.

    Science.gov (United States)

    Ma, Zipeng; Xie, Yuhan; Mao, Jie; Yang, Xuxu; Li, Tiefeng; Luo, Yingwu

    2017-08-01

    Dielectric elastomer (DE) actuators have been shown to have promising applications as soft electromechanical transducers in many emerging technologies. The DE actuators, which are capable of large actuation strain over a wide range of excitation frequencies, are highly desirable. Here, the first single-component DE of a triblock copolymer with attractive electromechanical performance is reported. Symmetric poly(styrene-b-butyl acrylate-b-styrene) (SBAS) is designed and synthesized. The SBAS actuator exhibits about 100% static actuation area strain and excellent dynamic performance, as evidenced by a wide half bandwidth of 300 Hz and a very high specific power of 1.2 W g-1 within the excitation frequency range of 300-800 Hz. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. On Data and Parameter Estimation Using the Variational Bayesian EM-algorithm for Block-fading Frequency-selective MIMO Channels

    DEFF Research Database (Denmark)

    Christensen, Lars P.B.; Larsen, Jan

    2006-01-01

    A general Variational Bayesian framework for iterative data and parameter estimation for coherent detection is introduced as a generalization of the EM-algorithm. Explicit solutions are given for MIMO channel estimation with Gaussian prior and noise covariance estimation with inverse-Wishart prior....... Simulation of a GSM-like system provides empirical proof that the VBEM-algorithm is able to provide better performance than the EM-algorithm. However, if the posterior distribution is highly peaked, the VBEM-algorithm approaches the EM-algorithm and the gain disappears. The potential gain is therefore...

  8. Seasonal Variations of the Ionosphere Scintillations Parameters Obtained from the Long Observations of the Power Cosmic Radio Sources at the Decameter Wave Range

    Science.gov (United States)

    Lytvynenko, O. A.; Panishko, S. K.

    Observations of the four power cosmic radio sources were carried out on the radio telescope (RT) URAN-4 during 1987-1990 and 1998-2007 at the frequencies 20 and 25 MHz. Effects of ionosphere and in particular existence of intensity fluctuations on the cosmic radio sources records, or scintillations, are essential at the decameter wave range. Long series of the ionosphere scintillations parameters such as indices, periods and spectrum slopes were obtained after observation data proceeding. Behavior of the seasonal variations was investigated on this data. Obtained dependencies were compared with the indices of the solar and geomagnetic activity.

  9. Genetic Variation in One-Carbon Metabolism and Changes in Metabolic Parameters in First-Episode Schizophrenia Patients.

    Science.gov (United States)

    Misiak, Blazej; Laczmanski, Lukasz; Sloka, Natalia Kinga; Szmida, Elzbieta; Slezak, Ryszard; Piotrowski, Patryk; Kiejna, Andrzej; Frydecka, Dorota

    2017-03-01

    In this study, we aimed to investigate the effects of polymorphisms in genes encoding 1-carbon metabolism enzymes on differential development of metabolic parameters during 12 weeks of treatment with second-generation antipsychotics in first-episode schizophrenia patients. The following polymorphisms in 1-carbon metabolism genes were genotyped: MTHFR (C677T and A1298C), MTHFD1 (G1958A), MTRR (A66G), and BHMT (G742A). A broad panel of metabolic parameters including body mass index, waist circumference, total cholesterol low and high density lipoproteins, triglycerides, homocysteine, folate, and vitamin B12 was determined. There was a significant effect of the interaction between the MTHFR C677T polymorphism and time on body mass index and waist circumference in the allelic and genotype analyses. Indeed, patients with the MTHFR 677CC genotype had higher increase in body mass index and waist circumference compared with other corresponding genotypes or the MTHFR 677T allele carriers (CT and TT genotypes). In addition, patients with the MTHFR 677TT genotype had higher waist circumference in all time points. Similarly, patients with the MTHFR 677TT genotype had higher body mass index in all time points, but this effect was not significant after correction for multiple testing. Our results indicate that the MTHFR C677T polymorphism may predict antipsychotic-induced weight gain. Effects of the MTHFR C677T polymorphism might be different in initial exposure to antipsychotics compared with long-term perspective.

  10. Variations in semen quality parameters of Ovchepolian pramenka rams according to the method of collection and the meteorological season

    Directory of Open Access Journals (Sweden)

    Nikolovski Martin

    2012-01-01

    Full Text Available The off-breeding season for rams is a time-limiting factor for their use in scientific aims. This research was set upon two aims: (1 to acknowledge the differences of semen quality collected throughout the year, and (2 to investigate which of the two commonly used methods for semen collection (artificial vagina - A.V. and electro ejaculation - E.E. could prove to be more favorable in the off-breeding period. Five Ovchepolian Pramenka rams were used for this investigation. They were divided in two groups: group 1 (two rams, which was subjected to A.V. method, and group 2 (three rams, which was subjected to E.E. method for semen collection. Semen evaluation included: volume, spermatozoa concentration, live spermatozoa, ejaculate density and motility. According to the season, results have a high statistical significance for the volume (P<0.01 and motility (P<0.001 parameters. Group 1 and 2 results versification showed a high statistical significance for the motility score (P<0.001, ejaculate volume (P<0.01 and percentage of live spermatozoa (P<0.01 parameters. In conclusion, the A.V. method is more favorable for semen collection in late autumn, winter and spring time when rams are out of the breeding season.

  11. Multi states electromechanical switch for energy efficient parallel data processing

    KAUST Repository

    Kloub, Hussam

    2011-04-01

    We present a design, simulation results and fabrication of electromechanical switches enabling parallel data processing and multi functionality. The device is applied in logic gates AND, NOR, XNOR, and Flip-Flops. The device footprint size is 2μm by 0.5μm, and has a pull-in voltage of 5.15V which is verified by FEM simulation. © 2011 IEEE.

  12. Setpoint Weighted PID Controller for the Electromechanical Actuator in Spacecraft

    OpenAIRE

    Sumathi, R.; Usha, M

    2014-01-01

    An intelligent control system for the rocket engine during electromechanical stage is designed and scrutinized in this paper. The rocket is the only vehicle that lift-offs the spacecraft in the space. But, the motion of the rocket can be influenced by internal and external disturbances. Furthermore, the rocket is a multi-input and multi-output nonlinear system whose dynamics are unstable and poorly understood. So the orientation of the spacecraft in precise position is so critical. Hence, att...

  13. Pair Identity and Smooth Variation Rules Applicable for the Spectroscopic Parameters of H2O Transitions Involving High-J States

    Science.gov (United States)

    Ma, Q.; Tipping, R. H.; Lavrentieva, N. N.

    2010-01-01

    Two basic rules (i.e. the pair identity and the smooth variation) applicable for H2O transitions involving high-J states have been discovered. The origins of these rules are the properties of the energy levels and wavefunctions of H2O states with the quantum number J above certain boundaries. As a result, for lines involving high-J states in individually defined groups, all their spectroscopic parameters (i.e. the transition wavenumber, intensity, pressure-broadened half-width, pressure-induced shift, and temperature exponent) must follow these rules. One can use these rules to screen spectroscopic data provided by databases and to identify possible errors. In addition, by using extrapolation methods within the individual groups, one is able to predict the spectroscopic parameters for lines in this group involving very high-J states. The latter are required in developing high-temperature molecular spectroscopic databases such as HITEMP.

  14. Stable exponential cosmological solutions with zero variation of G and three different Hubble-like parameters in the Einstein-Gauss-Bonnet model with a Λ-term

    Energy Technology Data Exchange (ETDEWEB)

    Ernazarov, K.K. [RUDN University, Institute of Gravitation and Cosmology, Moscow (Russian Federation); Ivashchuk, V.D. [RUDN University, Institute of Gravitation and Cosmology, Moscow (Russian Federation); VNIIMS, Center for Gravitation and Fundamental Metrology, Moscow (Russian Federation)

    2017-06-15

    We consider a D-dimensional gravitational model with a Gauss-Bonnet term and the cosmological term Λ. We restrict the metrics to diagonal cosmological ones and find for certain Λ a class of solutions with exponential time dependence of three scale factors, governed by three non-coinciding Hubble-like parameters H > 0, h{sub 1} and h{sub 2}, corresponding to factor spaces of dimensions m > 2, k{sub 1} > 1 and k{sub 2} > 1, respectively, with k{sub 1} ≠ k{sub 2} and D = 1 + m + k{sub 1} + k{sub 2}. Any of these solutions describes an exponential expansion of 3d subspace with Hubble parameter H and zero variation of the effective gravitational constant G. We prove the stability of these solutions in a class of cosmological solutions with diagonal metrics. (orig.)

  15. Simultaneous Estimation of Electromechanical Modes and Forced Oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Follum, Jim; Pierre, John W.; Martin, Russell

    2017-09-01

    Over the past several years, great strides have been made in the effort to monitor the small-signal stability of power systems. These efforts focus on estimating electromechanical modes, which are a property of the system that dictate how generators in different parts of the system exchange energy. Though the algorithms designed for this task are powerful and important for reliable operation of the power system, they are susceptible to severe bias when forced oscillations are present in the system. Forced oscillations are fundamentally different from electromechanical oscillations in that they are the result of a rogue input to the system, rather than a property of the system itself. To address the presence of forced oscillations, the frequently used AutoRegressive Moving Average (ARMA) model is adapted to include sinusoidal inputs, resulting in the AutoRegressive Moving Average plus Sinusoid (ARMA+S) model. From this model, a new Two-Stage Least Squares algorithm is derived to incorporate the forced oscillations, thereby enabling the simultaneous estimation of the electromechanical modes and the amplitude and phase of the forced oscillations. The method is validated using simulated power system data as well as data obtained from the western North American power system (wNAPS) and Eastern Interconnection (EI).

  16. Geometrical specifications accuracy influence on the quality of electromechanical devices

    Science.gov (United States)

    Glukhov, V. I.; Lakeenko, M. N.; Dolzhikov, S. N.

    2017-06-01

    To improve the quality of electromechanical products is possible due to the geometrical specifications optimization of values and tolerances. Electromechanical products longevity designates the rolling-contact bearings of the armature shaft. Longevity of the rolling-contact bearings is less than designed one, since assembly and fitting alter gaps, sizes and geometric tolerances for the working parts of the basic rolling bearing details. Geometrical models of the rolling-contact bearing details for the armature shaft and the end shield are developed on the basis of an electric locomotive traction motor in the present work. The basic elements of the details conjugating with the adjacent details and materializing the generalized and auxiliary coordinate systems are determined. Function, informativeness and the number of geometrical specifications for the elements location are specified. The recommendations on amending the design documentation due to geometrical models to improve the accuracy and the quality of the products are developed: the replacement of the common axis of the shaft’s technological datums by the common axis of the basic design datums; coaxiality tolerances for these design datums with respect to their common axis; the modifiers for these auxiliary datums and these datums location tolerances according to the principles of datums uniformity, inversion and the shortest dimension chains. The investigation demonstrated that the problem of enhancing the durability, longevity, and efficiency coefficient for electromechanical products can be solved with the systematic normalizations of geometrical specifications accuracy on the basis of the coordinate systems introduced in the standards on geometrical product specifications (GPS).

  17. Models of field-aligned currents needful to simulate the substorm variations of the electric field and other parameters observed by EISCAT

    Directory of Open Access Journals (Sweden)

    M. A. Volkov

    Full Text Available We have used the global numerical model of the coupled ionosphere-thermosphere-protonosphere system to simulate the electric-field, ion- and electron-temperature and -concentration variations observed by EISCAT during the substorm event of 25 March 1987. In our previous studies we adopted the model input data for field-aligned currents and precipitating electron fluxes to obtain an agreement between observed and modelled ionospheric variations. Now, we have calculated the field-aligned currents needful to simulate the substrom variations of the electric field and other parameters observed by EISCAT. The calculations of the field-aligned currents have been performed by means of numerical integration of the time-dependent continuity equation for the cold magnetospheric electrons. This equation was added to the system of the modelling equations including the equation for the electric-field potential to be solved jointly. In this case the inputs of the model are the spatial and time variations of the electric-field potential at the polar-cap boundaries and those of the cold magnetospheric electron concentration which have been adopted to obtain the agreement between the observed and modelled ionospheric variations for the substorm event of 25 March 1987. By this means it has been found that during the active phase of the substorm the current wedge is formed. It is connected with the region of the decreased cold magnetospheric electron content travelling westwards with a velocity of about 1 km s–1 at ionospheric levels.

  18. Investigation of plasma parameters at BATMAN for variation of the Cs evaporation asymmetry and comparing two driver geometries

    Science.gov (United States)

    Wimmer, C.; Fantz, U.; Aza, E.; Jovović, J.; Kraus, W.; Mimo, A.; Schiesko, L.

    2017-08-01

    The Neutral Beam Injection (NBI) system for fusion devices like ITER and, beyond ITER, DEMO requires large scale sources for negative hydrogen ions. BATMAN (Bavarian Test Machine for Negative ions) is a test facility attached with the prototype source for the ITER NBI (1/8 source size of the ITER source), dedicated to physical investigations due to its flexible access for diagnostics and exchange of source components. The required amount of negative ions is produced by surface conversion of hydrogen atoms or ions on caesiated surfaces. Several diagnostic tools (Optical Emission Spectroscopy, Cavity Ring-Down Spectroscopy for H-, Langmuir probes, Tunable Diode Laser Absorption Spectroscopy for Cs) allow the determination of plasma parameters in the ion source. Plasma parameters for two modifications of the standard prototype source have been investigated: Firstly, a second Cs oven has been installed in the bottom part of the back plate in addition to the regularly used oven in the top part of the back plate. Evaporation from the top oven only can lead to a vertically asymmetric Cs distribution in front of the plasma grid. Using both ovens, a symmetric Cs distribution can be reached - however, in most cases no significant change of the extracted ion current has been determined for varying Cs symmetry if the source is well-conditioned. Secondly, BATMAN has been equipped with a much larger, racetrack-shaped RF driver (area of 32×58 cm2) instead of the cylindrical RF driver (diameter of 24.5 cm). The main idea is that one racetrack driver could substitute two cylindrical drivers in larger sources with increased reliability and power efficiency. For the same applied RF power, the electron density is lower in the racetrack driver due to its five times higher volume. The fraction of hydrogen atoms to molecules, however, is at a similar level or even slightly higher, which is a promising result for application in larger sources.

  19. Seasonal Variation in Vitamin D in Association with Age, Inflammatory Cytokines, Anthropometric Parameters, and Lifestyle Factors in Older Adults

    Directory of Open Access Journals (Sweden)

    Leticia Elizondo-Montemayor

    2017-01-01

    Full Text Available Vitamin D deficiency is present even in sunny regions. Ageing decreases pre-vitamin D production in the skin and is associated with altered cytokine profile. We performed a multivariate analysis considering lifestyle factors, anthropometric, and inflammatory markers according to seasonal variation in Mexican healthy older adults. The same cohort was followed during 12 months. Vitamin D deficiency/insufficiency was found in 91.3% of the subjects despite living in appropriate latitude (25°40′0″N. 25(OHD levels remained below 74 years combined with WC (>88 cm and BMI (>32.7 showed a high probability (90% of vitamin D deficiency. Remarkably, an increase in one centimeter in WC decreased 25(OHD by 0.176 ng/mL, while an increase in one point BMI decreased 25(OHD by 0.534 ng/mL. A cutoff point of 74 years of age determined probability of vitamin D hipovitaminosis. Vitamin D deficiency was correlated with TNF-α serum levels, possibly increasing the susceptibility of older adults to a proinflammatory state and its related diseases.

  20. submitter An experimental evaluation of the fully coupled hysteretic electro-mechanical behaviour of piezoelectric actuators

    CERN Document Server

    Butcher, Mark; Giustiniani, Alessandro; Masi, Alessandro

    2016-01-01

    Piezoelectrics are the most commonly used of the multifunctional smart materials in industrial applications, because of their relatively low cost and ease of use in electric and electronic oriented applications. Nevertheless, while datasheets usually give just small signal quasi-static parameters, their full potential can only be exploited only if a full characterization is available because the maximum stroke or the higher piezo coupling coefficients are available at different electro-mechanical biases, where often small signal analysis is not valid. In this paper a method to get the quasi-static fully coupled characterization is presented. The method is tested on a commercial piezo actuator but can be extended to similar devices.

  1. Chattering-Free Sliding-Mode Control for Electromechanical Actuator with Backlash Nonlinearity

    Directory of Open Access Journals (Sweden)

    Dongqi Ma

    2017-01-01

    Full Text Available Considering the backlash nonlinearity and parameter time-varying characteristics in electromechanical actuators, a chattering-free sliding-mode control strategy is proposed in this paper to regulate the rudder angle and suppress unknown external disturbances. Different from most existing backlash compensation methods, a special continuous function is addressed to approximate the backlash nonlinear dead-zone model. Regarding the approximation error, unmodeled dynamics, and unknown external disturbances as a disturbance-like term, a strict feedback nonlinear model is established. Based on this nonlinear model, a chattering-free nonsingular terminal sliding-mode controller is proposed to achieve the rudder angle tracking with a chattering elimination and tracking dynamic performance improvement. A Lyapunov-based proof ensures the asymptotic stability and finite-time convergence of the closed-loop system. Experimental results have verified the effectiveness of the proposed method.

  2. Comparison of electromechanical properties and lattice distortions of different cuprate high temperature superconductors

    CERN Document Server

    Scheuerlein, C.; Grether, A; Rikel, M O; Hudspeth, J; Sugano, M; Ballarino, A; Bottura, L

    2016-01-01

    The electromechanical properties of different cuprate high-temperature superconductors, notably two ReBCO tapes, a reinforced and a nonreinforced Bi-2223 tape, and a Bi-2212 wire, have been studied. The axial tensile stress and strain, as well as the transverse compressive stress limits at which an irreversible critical current degradation occurs, are compared. The experimental setup has been integrated in a high-energy synchrotron beamline, and the self-field critical current and lattice parameter changes as a function of tensile stress and strain of a reinforced Bi-2223 tape have been measured simultaneously. Initially, the Bi-2223 filaments exhibit nearly linear elastic behavior up to the strain at which an irreversible degradation is observed. At 77 K, an axial Bi-2223 filament precompression of 0.09% in the composite tape and a Bi-2223 Poisson ratio ν = 0.21 have been determined.

  3. Electromechanical motion systems design and simulation

    CERN Document Server

    Moritz, Frederick G

    2013-01-01

    An introductory reference covering the devices, simulations and limitations in the control of servo systems Linking theoretical material with real-world applications, this book provides a valuable introduction to motion system design. The book begins with an overview of classic theory, its advantages and limitations, before showing how classic limitations can be overcome with complete system simulation. The ability to efficiently vary system parameters (such as inertia, friction, dead-band, damping), and quickly determine their effect on performance, stability, efficiency, is also described. T

  4. Variation in parameters related to growth in six genotypes of determinate shrub and indeterminate prostrated beans (Phaseolus vulgaris L.

    Directory of Open Access Journals (Sweden)

    Gustavo A Ligarreto

    2013-12-01

    Full Text Available A group of six common bean accessions of the Mesoamericano and Andino genetic groups of the Colombia national germplasm bank at the Corporación Colombiana de Investigación Agropecuaria (Corpoica was evaluated using 41 quantitatives. The results revealed that five components explained 70.33% of the total variability of the six accessions and 13 variable were selected that were essential for differentiating the variation, including: dry weight of primary leaves, dry weight of trifoliate leaves, pod dry weight, seed dry weight, number of leaves, leaf area ratio (LAR, relative growth rate (RGR and leaf temperature. Of the two groups of cultivars, the three Meso-American ones were less efficient in the translocation of assimilates than the Andean ones because they had a higher number of leaves and, even with a high LAR, seen as the ratio of assimilation material per unit of plant material, they did not present the higher RGR values on average. Specifically, the Meso-American cultivar Tolima 16, which presented a relatively high seed dry weight, and the Andean cultivars Mexico 497 and Antioquia 19, which had a relatively low number of leaves, presented a high pod dry weight and so were highly efficient. Mediante el empleo de 41 caracteres cuantitativos de tipo fisiológico se evaluó un grupo de seis accesiones de fríjol arbustivo de los acervos genéticos Mesoamericano y Andino del banco de germoplasma de la nación colombiano ubicado en la Corporación Colombiana de Investigación Agropecuaria (Corpoica

  5. Hematological parameters and the variations resulting from stress of Alouatta caraya during a wildlife rescue program in Brazil.

    Science.gov (United States)

    Sánchez-Sarmiento, Angélica María; Zwarg, Ticiana; Fernandes-Santos, Renata Carolina; Guimarães-Luiz, Thaís; Genoy-Puerto, Alexander; Matushima, Eliana Reiko

    2015-03-01

    Deforestation and habitat fragmentation are major threats to the conservation status of New World primates, such as the howler monkey (Alouatta caraya) in Brazil, where vegetation destruction is often associated with projects such as Small Hydro Power Plant (SHP) construction. The resulting stress from the implementation of this type of enterprise may be a factor that influences individual susceptibility against pathogens and can determine the success or failure of mitigation measures proposed by responsible and/or requested companies by environmental agencies. To perform health monitoring and to understand physiological changes that ensued from the stress of capturing and keeping primates in captivity, we determined the blood profile of A. caraya rescued at the time of capture (N = 15) and in captivity (N = 11). Complete blood counts (CBCs) performed at the time of capture showed hematological changes compatible with acute stress, such as evident neutrophilic leukocytosis (WBCs; females = 20.48 ± 7.26; males = 18.78 ± 10.39 × 10(9) /L). In captivity, monocytosis was observed in both sexes (females = 1.34 ± 0.26; males = 0.39 ± 0.32 × 10(9) /L; U-test, P = 0.01), suggesting chronic stress. In females, there was also statistically significant eosinopenia (0.28 ± 0.10 × 10(9) /L; U-test, P = 0.01) and hematocrit increases (39.00 ± 1.41%; U-test, P = 0.01). Thus, data shows the impact of both capture related acute stress as well as captivity chronic stress, suggesting that primate management in the implementation of these projects causes significant changes in physiological parameters and, consequently, animal health. Whereas chronic stress is an inducer of immunosuppression and susceptibility to pathogen factors, monitoring hematological parameters in captive animals can act as an indicator of health status, contributing to the success of management and conservation wildlife programs. Am

  6. Parametric analysis of electromechanical and fatigue performance of total knee replacement bearing with embedded piezoelectric transducers

    Science.gov (United States)

    Safaei, Mohsen; Meneghini, R. Michael; Anton, Steven R.

    2017-09-01

    Total knee arthroplasty is a common procedure in the United States; it has been estimated that about 4 million people are currently living with primary knee replacement in this country. Despite huge improvements in material properties, implant design, and surgical techniques, some implants fail a few years after surgery. A lack of information about in vivo kinetics of the knee prevents the establishment of a correlated intra- and postoperative loading pattern in knee implants. In this study, a conceptual design of an ultra high molecular weight (UHMW) knee bearing with embedded piezoelectric transducers is proposed, which is able to measure the reaction forces from knee motion as well as harvest energy to power embedded electronics. A simplified geometry consisting of a disk of UHMW with a single embedded piezoelectric ceramic is used in this work to study the general parametric trends of an instrumented knee bearing. A combined finite element and electromechanical modeling framework is employed to investigate the fatigue behavior of the instrumented bearing and the electromechanical performance of the embedded piezoelectric. The model is validated through experimental testing and utilized for further parametric studies. Parametric studies consist of the investigation of the effects of several dimensional and piezoelectric material parameters on the durability of the bearing and electrical output of the transducers. Among all the parameters, it is shown that adding large fillet radii results in noticeable improvement in the fatigue life of the bearing. Additionally, the design is highly sensitive to the depth of piezoelectric pocket. Finally, using PZT-5H piezoceramics, higher voltage and slightly enhanced fatigue life is achieved.

  7. Parametric analysis of electromechanical and fatigue performance of total knee replacement bearing with embedded piezoelectric transducers.

    Science.gov (United States)

    Safaei, Mohsen; Meneghini, R Michael; Anton, Steven R

    2017-09-01

    Total knee arthroplasty (TKA) is a common procedure in the United States; it has been estimated that about 4 million people are currently living with primary knee replacement in this country. Despite huge improvements in material properties, implant design, and surgical techniques, some implants fail a few years after surgery. A lack of information about in vivo kinetics of the knee prevents the establishment of a correlated intra- and postoperative loading pattern in knee implants. In this study, a conceptual design of an ultra high molecular weight (UHMW) knee bearing with embedded piezoelectric transducers is proposed, which is able to measure the reaction forces from knee motion as well as harvest energy to power embedded electronics. A simplified geometry consisting of a disk of UHMW with a single embedded piezoelectric ceramic is used in this work to study the general parametric trends of an instrumented knee bearing. A combined finite element and electromechanical modeling framework is employed to investigate the fatigue behavior of the instrumented bearing and the electromechanical performance of the embedded piezoelectric. The model is validated through experimental testing and utilized for further parametric studies. Parametric studies consist of the investigation of the effects of several dimensional and piezoelectric material parameters on the durability of the bearing and electrical output of the transducers. Among all the parameters, it is shown that adding large fillet radii results in noticeable improvement in the fatigue life of the bearing. Additionally, the design is highly sensitive to the depth of piezoelectric pocket. Finally, using PZT-5H piezoceramics, higher voltage and slightly enhanced fatigue life is achieved.

  8. Variation Quality and Kinetic Parameter of Commercial n-3 PUFA-Rich Oil during Oxidation via Rancimat.

    Science.gov (United States)

    Yang, Kai-Min; Chiang, Po-Yuan

    2017-03-28

    Different biological sources of n -3 polyunsaturated fatty acids ( n -3 PUFA) in mainstream commercial products include algae and fish. Lipid oxidation in n -3 PUFA-rich oil is the most important cause of its deterioration. We investigated the kinetic parameters of n -3 PUFA-rich oil during oxidation via Rancimat (at a temperature range of 70~100 °C). This was done on the basis of the Arrhenius equation, which indicates that the activation energies ( E a) for oxidative stability are 82.84-96.98 KJ/mol. The chemical substrates of different oxidative levels resulting from oxidation via Rancimat at 80 °C were evaluated. At the initiation of oxidation, the tocopherols in the oil degraded very quickly, resulting in diminished protection against further oxidation. Then, the degradation of the fatty acids with n -3 PUFA-rich oil was evident because of decreased levels of PUFA along with increased levels of saturated fatty acids (SFA). The quality deterioration from n -3 PUFA-rich oil at the various oxidative levels was analyzed chemometrically. The anisidine value (p-AV, r: 0.92) and total oxidation value (TOTOX, r: 0.91) exhibited a good linear relationship in a principal component analysis (PCA), while oxidative change and a significant quality change to the induction period (IP) were detected through an agglomerative hierarchical cluster (AHC) analysis.

  9. Variation in antioxidant enzyme activities, growth and some physiological parameters of bitter melon (Momordica charantia) under salinity and chromium stress.

    Science.gov (United States)

    Bahrami, Mahsa; Heidari, Mostafa; Ghorbani, Hadi

    2016-07-01

    In general, salinity and heavy metals interfere with several physiological processes and reduce plant growth. In order to evaluate of three levels of salinity (0, 4 and 8 ds m(-1)) and three concentration of chromium (0, 10 and 20 mg kg(-1) soil) in bitter melon (Momordica charantia), a plot experiment was conducted in greenhouse at university of Shahrood, Iran. The results revealed that chromium treatment had no significant affect on fresh and dry weight, but salinity caused reduction of fresh and dry weight in growth parameter. Salinity and chromium enhanced antioxidant enzymes activities like catalase (CAT), guaiacol peroxidase (GPX) and sodium content in leaves. However salinity and chromium treatments had no effect on potassium, phosphorus in leaves, soluble carbohydrate concentration in leaves and root, but decreased the carotenoid content in leaves. On increasing salinity from control to 8 ds m(-1) chlorophyll a, b and anthocyanin content decreased by 41.6%, 61.1% and 26.5% respectively but chromium treatments had no significant effect on these photosynthetic pigments.

  10. Accuracy of two digital implant impression systems based on confocal microscopy with variations in customized software and clinical parameters.

    Science.gov (United States)

    Giménez, Beatriz; Pradíes, Guillermo; Martínez-Rus, Francisco; Özcan, Mutlu

    2015-01-01

    To evaluate the accuracy of two digital impression systems based on the same technology but different postprocessing correction modes of customized software, with consideration of several clinical parameters. A maxillary master model with six implants located in the second molar, second premolar, and lateral incisor positions was fitted with six cylindrical scan bodies. Scan bodies were placed at different angulations or depths apical to the gingiva. Two experienced and two inexperienced operators performed scans with either 3D Progress (MHT) or ZFX Intrascan (Zimmer Dental). Five different distances between implants (scan bodies) were measured, yielding five data points per impression and 100 per impression system. Measurements made with a high-accuracy three-dimensional coordinate measuring machine (CMM) of the master model acted as the true values. The values obtained from the digital impressions were subtracted from the CMM values to identify the deviations. The differences between experienced and inexperienced operators and implant angulation and depth were compared statistically. Experience of the operator, implant angulation, and implant depth were not associated with significant differences in deviation from the true values with both 3D Progress and ZFX Intrascan. Accuracy in the first scanned quadrant was significantly better with 3D Progress, but ZFX Intrascan presented better accuracy in the full arch. Neither of the two systems tested would be suitable for digital impression of multiple-implant prostheses. Because of the errors, further development of both systems is required.

  11. Electromechanical-assisted training for walking after stroke.

    Science.gov (United States)

    Mehrholz, Jan; Thomas, Simone; Werner, Cordula; Kugler, Joachim; Pohl, Marcus; Elsner, Bernhard

    2017-05-10

    Electromechanical- and robotic-assisted gait-training devices are used in rehabilitation and might help to improve walking after stroke. This is an update of a Cochrane Review first published in 2007. To investigate the effects of automated electromechanical- and robotic-assisted gait-training devices for improving walking after stroke. We searched the Cochrane Stroke Group Trials Register (last searched 9 August 2016), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2016, Issue 8), MEDLINE in Ovid (1950 to 15 August 2016), Embase (1980 to 15 August 2016), CINAHL (1982 to 15 August 2016), AMED (1985 to 15 August 2016), Web of Science (1899 to 16 August 2016), SPORTDiscus (1949 to 15 September 2012), the Physiotherapy Evidence Database (PEDro) (searched 16 August 2016), and the engineering databases COMPENDEX (1972 to 16 November 2012) and Inspec (1969 to 26 August 2016). We handsearched relevant conference proceedings, searched trials and research registers, checked reference lists, and contacted authors in an effort to identify further published, unpublished, and ongoing trials. We included all randomised controlled trials and randomised controlled cross-over trials in people over the age of 18 years diagnosed with stroke of any severity, at any stage, in any setting, evaluating electromechanical- and robotic-assisted gait training versus normal care. Two review authors independently selected trials for inclusion, assessed methodological quality and risk of bias, and extracted the data. The primary outcome was the proportion of participants walking independently at follow-up. We included 36 trials involving 1472 participants in this review update. Electromechanical-assisted gait training in combination with physiotherapy increased the odds of participants becoming independent in walking (odds ratio (random effects) 1.94, 95% confidence interval (CI) 1.39 to 2.71; P functional electrical stimulation. Our planned subgroup analysis

  12. A Systems Engineering Approach to Electro-Mechanical Actuator Diagnostic and Prognostic Development

    Data.gov (United States)

    National Aeronautics and Space Administration — The authors have formulated a Comprehensive Systems Engineering approach to Electro-Mechanical Actuator (EMA) Prognostics and Health Management (PHM) system...

  13. Class structure of electromechanical energy converter models with UML-diagrams application

    Directory of Open Access Journals (Sweden)

    V.Ye. Plyugin

    2014-04-01

    Full Text Available Theoretical results are presented, mathematical model formation by means of inheritance from a generalized class template is shown for a general electromechanical energy converter.

  14. Internet of Things-Based Arduino Intelligent Monitoring and Cluster Analysis of Seasonal Variation in Physicochemical Parameters of Jungnangcheon, an Urban Stream

    Directory of Open Access Journals (Sweden)

    Byungwan Jo

    2017-03-01

    Full Text Available In the present case study, the use of an advanced, efficient and low-cost technique for monitoring an urban stream was reported. Physicochemical parameters (PcPs of Jungnangcheon stream (Seoul, South Korea were assessed using an Internet of Things (IoT platform. Temperature, dissolved oxygen (DO, and pH parameters were monitored for the three summer months and the first fall month at a fixed location. Analysis was performed using clustering techniques (CTs, such as K-means clustering, agglomerative hierarchical clustering (AHC, and density-based spatial clustering of applications with noise (DBSCAN. An IoT-based Arduino sensor module (ASM network with a 99.99% efficient communication platform was developed to allow collection of stream data with user-friendly software and hardware and facilitated data analysis by interested individuals using their smartphones. Clustering was used to formulate relationships among physicochemical parameters. K-means clustering was used to identify natural clusters using the silhouette coefficient based on cluster compactness and looseness. AHC grouped all data into two clusters as well as temperature, DO and pH into four, eight, and four clusters, respectively. DBSCAN analysis was also performed to evaluate yearly variations in physicochemical parameters. Noise points (NOISE of temperature in 2016 were border points (ƥ, whereas in 2014 and 2015 they remained core points (ɋ, indicating a trend toward increasing stream temperature. We found the stream parameters were within the permissible limits set by the Water Quality Standards for River Water, South Korea.

  15. Assessment of soil electromagnetic parameters and their variation with soil water, salts: a comparison among EMI and TDR measuring methods

    Science.gov (United States)

    Chaali, Nesrine; Coppola, Antonio; Comegna, Alessandro; Dragonetti, Giovanna

    2015-04-01

    Numerous studies have analyzed the possibility of the extension of Electromagnetic Induction EMI calibration coefficients determined at field scale, to predict the depth distribution of bulk electrical conductivity ECb within unmonitored sites and/or times, in order to appraise the effect of salts dynamics on soils and plants. However, in the literature, it has been determined that the extension of those EMI calibration coefficients can be awkward since the calibration parameters are highly site-specific because of changes in water content, temperature, root development, soil physical properties, etc... So they can only be used in sites having similar characteristics in terms of EMI. Furthermore there is a difference in the observation windows of EMI sensors and of sensors (Time Domain Reflectometry TDR, Electrical Resistance Tomography ERT, ect...) used for measuring the ECb to be then used for the calibration and validation of the EMI. By consequence the actual variability of the soil salinity will be hidden due to the fact that data coming from EMI and other sensors have different variability patterns and structure, and are then influenced by different noises. The main objectives of this work were: 1) develop a practical and cost-effective technique that uses TDR data as ground-truth data for calibrating and validating of the EMI larger scale sensor, 2) using a Fourier transform FT analysis by applying a specific noise filter to the original data, to find the correlations between the TDR and the EMI data. An experiment was designed by irrigating three transects of green beans, 30 m long each, with three irrigation salinity inputs (1dSm-1, 3dSm-1, 6dSm-1). The irrigation volumes were estimated by measuring soil water content at different depths by using a Diviner 2000. During the experiment, the EM in both the vertical (EMV) and horizontal (EMH) configurations were regularly measured by a Geonics EM38 device. TDR probes were inserted vertically at the soil

  16. 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.

  17. Influence of passive muscle tension on electromechanical delay in humans.

    Directory of Open Access Journals (Sweden)

    Lilian Lacourpaille

    Full Text Available BACKGROUND: Electromechanical delay is the time lag between onsets of muscle activation and muscle force production and reflects both electro-chemical processes and mechanical processes. The aims of the present study were two-fold: to experimentally determine the slack length of each head of the biceps brachii using elastography and to determine the influence of the length of biceps brachii on electromechanical delay and its electro-chemical/mechanical processes using very high frame rate ultrasound. METHODS/RESULTS: First, 12 participants performed two passive stretches to evaluate the change in passive tension for each head of the biceps brachii. Then, they underwent two electrically evoked contractions from 120 to 20° of elbow flexion (0°: full extension, with the echographic probe maintained over the muscle belly and the myotendinous junction of biceps brachii. The slack length was found to occur at 95.5 ± 6.3° and 95.3 ± 8.2° of the elbow joint angle for the long and short heads of the biceps brachii, respectively. The electromechanical delay was significantly longer at 120° (16.9 ± 3.1 ms; p0.95. CONCLUSION: In contrast to previous observations on gastrocnemius medialis, the onset of muscle motion and the onset of myotendinous junction motion occurred simultaneously regardless of the length of the biceps brachii. That suggests that the between-muscles differences reported in the literature cannot be explained by different muscle passive tension but instead may be attributable to muscle architectural differences.

  18. Mechanism of electromechanical coupling in voltage-gated potassium channels

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    Rikard eBlunck

    2012-09-01

    Full Text Available Voltage-gated ion channels play a central role in the generation of action potentials in the nervous system. They are selective for one type of ion – sodium, calcium or potassium. Voltage-gated ion channels are composed of a central pore that allows ions to pass through the membrane and four peripheral voltage sensing domains that respond to changes in the membrane potential. Upon depolarization, voltage sensors in voltage-gated potassium channels (Kv undergo conformational changes driven by positive charges in the S4 segment and aided by pairwise electrostatic interactions with the surrounding voltage sensor. Structure-function relations of Kv channels have been investigated in detail, and the resulting models on the movement of the voltage sensors now converge to a consensus; the S4 segment undergoes a combined movement of rotation, tilt and vertical displacement in order to bring 3-4 e+ each through the electric field focused in this region. Nevertheless, the mechanism by which the voltage sensor movement leads to pore opening, the electromechanical coupling, is still not fully understood. Thus, recently, electromechanical coupling in different Kv channels has been investigated with a multitude of techniques including electrophysiology, 3D crystal structures, fluorescence spectroscopy and molecular dynamics simulations. Evidently, the S4-S5 linker, the covalent link between the voltage sensor and pore, plays a crucial role. The linker transfers the energy from the voltage sensor movement to the pore domain via an interaction with the S6 C-termini, which are pulled open during gating. In addition, other contact regions have been proposed. This review aims to provide (i an in-depth comparison of the molecular mechanisms of electromechanical coupling in different Kv channels; (ii insight as to how the voltage sensor and pore domain influence one another; and (iii theoretical predictions on the movement of the cytosolic face of the KV channels

  19. Optical driven electromechanical transistor based on tunneling effect.

    Science.gov (United States)

    Jin, Leisheng; Li, Lijie

    2015-04-15

    A new electromechanical transistor based on an optical driven vibrational ring structure has been postulated. In the device, optical power excites the ring structure to vibrate, which acts as the shuttle transporting electrons from one electrode to the other forming the transistor. The electrical current of the transistor is adjusted by the optical power. Coupled opto-electro-mechanical simulation has been performed. It is shown from the dynamic analysis that the stable working range of the transistor is much wider than that of the optical wave inside the cavity, i.e., the optical resonance enters nonperiodic states while the mechanical vibration of the ring is still periodic.

  20. A BRB Based Fault Prediction Method of Complex Electromechanical Systems

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    Bangcheng Zhang

    2015-01-01

    Full Text Available Fault prediction is an effective and important approach to improve the reliability and reduce the risk of accidents for complex electromechanical systems. In order to use the quantitative information and qualitative knowledge efficiently to predict the fault, a new model is proposed on the basis of belief rule base (BRB. Moreover, an evidential reasoning (ER based optimal algorithm is developed to train the fault prediction model. The screw failure in computer numerical control (CNC milling machine servo system is taken as an example and the fault prediction results show that the proposed method can predict the behavior of the system accurately with combining qualitative knowledge and some quantitative information.

  1. Revolution of Sensors in Micro-Electromechanical Systems

    Science.gov (United States)

    Esashi, Masayoshi

    2012-08-01

    Microsensors realized by micro-electromechanical systems (MEMS) technology play a key role as the input devices of systems. In this report, the following sensors are reviewed: piezoresistive and capacitive pressure sensors, surface acoustic wave (SAW) wireless pressure sensors, tactile sensor networks for robots, accelerometers, angular velocity sensors (gyroscopes), range image sensors using optical scanners, infrared imagers, chemical sensing systems as Fourier transform infrared (FTIR) spectroscopy and gas chromatography, flow sensors for fluids, and medical sensors such as ultrafine optical-fiber blood pressure sensors and implantable pressure sensors.

  2. Modeling and Simulation of Nonlinear Micro-electromechanical Circular Plate

    Directory of Open Access Journals (Sweden)

    Chin-Chia Liu

    2013-09-01

    Full Text Available In the present study, the hybrid differential transformation and finite difference method is applied to analyze the dynamic behavior of the nonlinear micro-electromechanical circular plate actuated by combined DC / AC loading schemes. The analysis takes account of the axial residual stress and hydrostatic pressure acting on micro circular plate upper surface. The dynamic response of the plate as a function of the magnitude of the AC driving voltage is explored. Moreover, the effect of the initial gap height on the pull-in voltage of the plate is systematically explored.

  3. Electromechanical stability of buckled thin metal films on elastomer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Donyoung; Hwang, Hyun-Sik; Khang, Dahl-Young, E-mail: dykhang@yonsei.ac.kr

    2011-06-01

    Oxidizable metals such as Al are found to become highly resistive when exposed to air in buckled state, > 10x resistance increase compared to that in flat configuration. On the other hand, noble metal and oxide conductor films, such as Au and indium tin oxide show negligible resistance increase. The enhanced oxidation of grain boundaries that are exposed to air when buckled is found to be responsible for the observed electromechanical stability. Simple yet effective method, i.e., thin capping layer of noble metal, to prevent the oxidation of non-noble metal is proposed and experimentally verified.

  4. Improved electromechanical behavior in castable dielectric elastomer actuators

    Science.gov (United States)

    Akbari, Samin; Rosset, Samuel; Shea, Herbert R.

    2013-02-01

    Non-viscoelastic castable elastomers are replacing the polyacrylate VHB films in the new generations of dielectric elastomer actuators (DEAs) to achieve fast and reliable actuation. We introduce the optimum prestretch conditions to enhance the electromechanical behavior of the castable DEAs resulting in large actuation strain. For castable actuator in which the thickness is selected independent of the prestretch, uniaxial prestretch mode offers the highest actuation strain in the transverse direction compared to biaxial and pure shear. We experimentally demonstrate that miniaturization hinders the loss of tension and up to 85% linear actuation strain is generated with a 300 × 300 μm2 polydimethylsiloxanes-based DEA.

  5. Inherent Problems in Designing Two-Failure Tolerant Electromechanical Actuators

    Science.gov (United States)

    Hornyak, S.

    1984-01-01

    An electromechanical ac-powered rotary actuated four-bar linkage system for rotating the Shuttle/Centaur deployment adapter is described. The essential features of the deployment adapter rotation system (DARS) are increased reliability for mission success and maximum practical hazard control for safety. The requirements, concept development, hardware configuration, quality assurance provisions, and techniques used to meet two-fault tolerance requirements are highlighted. The rationale used to achieve a degree of safety equivalent of that of two-failure tolerance is presented. Conditions that make this approach acceptable, including single failure point components with regard to redundancy versus credibility of failure modes, are also discussed.

  6. Troubleshooting of an Electromechanical System (Westinghouse PLC Controlling a Pneumatic Robot). High-Technology Training Module.

    Science.gov (United States)

    Tucker, James D.

    This training module on the troubleshooting of an electromechanical system, The Westinghouse Programmable Logic Controller (PLC) controlling a pneumatic robot, is used for a troubleshooting unit in an electromechanical systems/robotics and automation systems course. In this unit, students locate and repair a defect in a PLC-operated machine. The…

  7. Field tests for assessing electrical protection performance regarding electromechanical protection relays

    Directory of Open Access Journals (Sweden)

    Luis Alfredo Esteves

    2012-12-01

    Full Text Available This article describes designing and using a series of field tests (such as pick-up test and operating characteristics aimed at ascertaining the correct operation of relays’ electromechanical protection. The characteristic elements involved in adjusting electromechanical protection relays are presented.

  8. Microstructural changes and effect of variation of lattice strain on positron annihilation lifetime parameters of zinc ferrite nanocomposites prepared by high enegy ball-milling

    Directory of Open Access Journals (Sweden)

    Abhijit Banerjee

    2012-12-01

    Full Text Available Zn-ferrite nanoparticles were synthesized at room temperature by mechanical alloying the stoichiometric (1:1 mol% mixture of ZnO and α-Fe2O3 powder under open air. Formation of both normal and inverse spinel ferrite phases was noticed after 30 minutes and 2.5 hours ball milling respectively and the content of inverse spinel phase increased with increasing milling time. The phase transformation kinetics towards formation of ferrite phases and microstructure characterization of ball milled ZnFe2O4 phases was primarily investigated by X-ray powder diffraction pattern analysis. The relative phase abundances of different phases, crystallite size, r.m.s. strain, lattice parameter change etc. were estimated from the Rietveld powder structure refinement analysis of XRD data. Positron annihilation lifetime spectra of all ball milled samples were deconvoluted with three lifetime parameters and their variation with milling time duration was explained with microstructural changes and formation of different phases with increase of milling time duration.

  9. Spatial and seasonal variation of microphytoplankton community and the correlation with environmental parameters in a hypereutrophic tropical estuary - Maranhão - Brazil

    Directory of Open Access Journals (Sweden)

    Ana Karoline Duarte dos Santos

    Full Text Available Abstract The Bacanga River Estuary has a hydrodynamic behavior and its tidal flow is limited by a dam. It is considered as a hypertrophic environment that receives daily high loads of domestic sewage without treatment. This study aimed to evaluate the spatial and temporal variation of phytoplankton community and its relationship with environmental parameters. Bi-monthly sampling campaigns were carried out at six fixed sites between 2012 and 2013. Physical-chemical and biological parameters were collected (chlorophyll a, phytoplankton composition and abundance to perform the statistical correlations. The results indicate that phytoplankton community is mostly represented by diatoms, with Skeletonema costatum being the dominant species responsible for bloom in April and June of 2012. The dominance of this species is related to the high silicate concentrations, pH and turbidity. Other blooms events as well as the Euglena gracilis and Chlamydomonas sp. were recorded in February 2013, when the total phosphorus concentrations were high and the dissolved oxygen concentrations were higher. Dinoflagellates, cyanobacteria and diatom Thallassiosira sp. were widely distributed in the dry period and highly correlated with salinity, water transparency and nutrients. Hence, the distribution of phytoplankton community is more defined seasonally, rather than spatially.

  10. Short Time Impulse Response Function (STIRF) for automatic evaluation of the variation of the dynamic parameters of reinforced concrete framed structures during strong earthquakes.

    Science.gov (United States)

    Carlo Ponzo, Felice; Ditommaso, Rocco

    2015-04-01

    This study presents an innovative strategy for automatic evaluation of the variable fundamental frequency and related damping factor of nonlinear structures during strong motion phases. Most of methods for damage detection are based on the assessment of the variations of the dynamic parameters characterizing the monitored structure. A crucial aspect of these methods is the automatic and accurate estimation of both structural eigen-frequencies and related damping factors also during the nonlinear behaviour. A new method, named STIRF (Short-Time Impulse Response Function - STIRF), based on the nonlinear interferometric analysis combined with the Fourier Transform (FT) here is proposed in order to allow scientists and engineers to characterize frequencies and damping variations of a monitored structure. The STIRF approach helps to overcome some limitation derived from the use of techniques based on simple Fourier Transform. These latter techniques provide good results when the response of the monitored system is stationary, but fails when the system exhibits a non-stationary, time-varying behaviour: even non-stationary input, soil-foundation and/or adjacent structures interaction phenomena can show the inadequacy of classic techniques to analysing the nonlinear and/or non-stationary behaviour of structures. In fact, using this kind of approach it is possible to improve some of the existing methods for the automatic damage detection providing stable results also during the strong motion phase. Results are consistent with those expected if compared with other techniques. The main advantage derived from the use of the proposed approach (STIRF) for Structural Health Monitoring is based on the simplicity of the interpretation of the nonlinear variations of the fundamental frequency and the related equivalent viscous damping factor. The proposed methodology has been tested on both numerical and experimental models also using data retrieved from shaking table tests. Based on

  11. Modeling and performance evaluation of an electromechanical valve actuator for a camless IC engine

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, Eid [Automotive and Tractors Engineering, Faculty of Engineering, Helwan University, Cairo (Egypt)

    2012-07-01

    Valve train control is one of the best strategies for optimizing efficiency and emissions of Internal Combustion (IC) engines. Applications of solenoid valve actuators in (IC) engines can facilitate operations such as variable valve timing and variable valve lifting for improved the engine performance, fuel economy and reduce emission, the electromechanical valve actuator (EMVA) uses solenoid to actuate valve movement independently for the application of (IC) engine. In this work presents the effects of design and operating parameters on the system dynamic performances of the actuator and the proposed an (EMVA) structure by incorporating the hybrid magneto-motive force (MMF) implementation in which the magnetic flux is combined by the coil excitation and permanent magnets. A two-degree-of-freedom lumped parameter model is used to simulate the response of valve actuator system in the opening and closing. The model and control of an electromagnetic valve (EMV) are described. This is done using electromagnetic force to open and close the valve and a controller regulates the motion specifications required. The developments controller is based on a state-space description of the actuator that is derived based on physical principles and parameter identification. Linear-quadratic regulator design (LQR) optimal control is designed with the evaluation reasonable the performance and energy of (EMV) valve are obtained with the design.

  12. Optimal design and control of an electromechanical transfemoral prosthesis with energy regeneration.

    Directory of Open Access Journals (Sweden)

    Farbod Rohani

    Full Text Available In this paper, we present the design of an electromechanical above-knee active prosthesis with energy storage and regeneration. The system consists of geared knee and ankle motors, parallel springs for each motor, an ultracapacitor, and controllable four-quadrant power converters. The goal is to maximize the performance of the system by finding optimal controls and design parameters. A model of the system dynamics was developed, and used to solve a combined trajectory and design optimization problem. The objectives of the optimization were to minimize tracking error relative to human joint motions, as well as energy use. The optimization problem was solved by the method of direct collocation, based on joint torque and joint angle data from ten subjects walking at three speeds. After optimization of controls and design parameters, the simulated system could operate at zero energy cost while still closely emulating able-bodied gait. This was achieved by controlled energy transfer between knee and ankle, and by controlled storage and release of energy throughout the gait cycle. Optimal gear ratios and spring parameters were similar across subjects and walking speeds.

  13. Molecular forces in electromechanical integrated electrostatic harmonic actuator

    Directory of Open Access Journals (Sweden)

    Lizhong Xu

    2017-10-01

    Full Text Available Authors invent an electromechanical integrated electrostatic harmonic actuator. It is more favorable for miniaturization of the electromechanical devices. As the dimensions of the actuator decreases, the effects of the Casimir and van der Waals forces become obvious. Here, effects of the molecular forces on the operating behavior of the actuator are investigated theoretically investigated by a parametric study. The equations of the radial displacements of the flexible ring and the output torque for the actuator are deduced for three different situations: only considering electrostatic force, considering electrostatic and van der Waals forces, and considering electrostatic and the Casimir forces. The effects of van der Waals or the Casimir force on the radial displacements of the flexible ring and the output torque for the actuator are analyzed. Results show that van der Waals or the Casimir forces has obvious effects on the output torque of the actuator for small structure dimension. The results are useful in theory and technique studies on further miniaturization of the actuator.

  14. Molecular forces in electromechanical integrated electrostatic harmonic actuator

    Science.gov (United States)

    Xu, Lizhong; Shi, Xufei

    2017-10-01

    Authors invent an electromechanical integrated electrostatic harmonic actuator. It is more favorable for miniaturization of the electromechanical devices. As the dimensions of the actuator decreases, the effects of the Casimir and van der Waals forces become obvious. Here, effects of the molecular forces on the operating behavior of the actuator are investigated theoretically investigated by a parametric study. The equations of the radial displacements of the flexible ring and the output torque for the actuator are deduced for three different situations: only considering electrostatic force, considering electrostatic and van der Waals forces, and considering electrostatic and the Casimir forces. The effects of van der Waals or the Casimir force on the radial displacements of the flexible ring and the output torque for the actuator are analyzed. Results show that van der Waals or the Casimir forces has obvious effects on the output torque of the actuator for small structure dimension. The results are useful in theory and technique studies on further miniaturization of the actuator.

  15. A review of mechanical and electromechanical properties of piezoelectric nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa, Horacio D.; Bernal, Rodrigo A.; Minary-Jolandan, Majid [Department of Mechanical Engineering, Northwestern University, Evanston, IL (United States)

    2012-09-04

    Piezoelectric nanowires are promising building blocks in nanoelectronic, sensing, actuation and nanogenerator systems. In spite of great progress in synthesis methods, quantitative mechanical and electromechanical characterization of these nanostructures is still limited. In this article, the state-of-the art in experimental and computational studies of mechanical and electromechanical properties of piezoelectric nanowires is reviewed with an emphasis on size effects. The review covers existing characterization and analysis methods and summarizes data reported in the literature. It also provides an assessment of research needs and opportunities. Throughout the discussion, the importance of coupling experimental and computational studies is highlighted. This is crucial for obtaining unambiguous size effects of nanowire properties, which truly reflect the effect of scaling rather than a particular synthesis route. We show that such a combined approach is critical to establish synthesis-structure-property relations that will pave the way for optimal usage of piezoelectric nanowires. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Electromechanical and robot-assisted arm training for improving generic activities of daily living, arm function, and arm muscle strength after stroke.

    Science.gov (United States)

    Mehrholz, Jan; Hädrich, Anja; Platz, Thomas; Kugler, Joachim; Pohl, Marcus

    2012-06-13

    %). Electromechanical and robot-assisted arm training did not increase the risk of patients to drop out (RD 0.00, 95% CI -0.04 to 0.04, P = 0.82, I(2) = 0.0%), and adverse events were rare. Patients who receive electromechanical and robot-assisted arm training after stroke are more likely to improve their generic activities of daily living. Paretic arm function may also improve, but not arm muscle strength. However, the results must be interpreted with caution because there were variations between the trials in the duration and amount of training, type of treatment, and in the patient characteristics.

  17. Growth parameters and density variation of a queen conch, Strombus gigas (Neotaenioglossa: Strombidae), population from Xel-Ha park, a marine protected area.

    Science.gov (United States)

    Baqueiro Cárdenas, Erick; Aldana Aranda, Dalila

    2014-03-01

    The queen conch, Strombus gigas, is a gastropod of commercial importance in the Caribbean. Population studies are based on size frequency analysis, using either length or weight parameters for the whole live organism. This contribution used mark-recapture data to estimate the Von Bertalanffy equation parameters and population number variation within a non harvest population from a protected area, to clarify the biometric parameters that better suit for the whole population, or for the juvenile and adult fractions. Conchs from Xel-Ha Park were monthly sampled from November 2001 to August 2005. Every conch found was measured and marked with a numbered tag that identified month and locality; and monthly abundance was estimated with Jolly's method. Length, lip thickness and weight increments were used to estimate the Von Bertalanffy growth equation parameters with Appeldoorn's subroutine of FISAT program. The population number varied through the study, with a minimum of 49 in April 2003 and maximum of 9 848 during June 2005. Conchs make only temporary use of Xel-Ha cove. Shell length gave the best fit for the juvenile fraction: L(infinity)=251, K=0.3, C=0.8 Wp=0.3; and lip thickness for adults: L(infinity)=47.78, K=0.17, C=0.1, Wp=0.86, while, the whole population was better represented by weight: L(infinity)=3850, K=0.36, C=0.8, Wp=0.3. A maximum age of 19 years was estimated from the population. Natural mortality was 0.49/year for juveniles and 0.29/year for adults. There were two pulses of recruitment: fall-winter and summer. It is concluded that population studies from length frequency data, should be analyzed independently in two groups, shell for the juvenile fraction and lip thickness for the adult fraction, or if it is not possible to analyze the population fractions separately, weight should be used to avoid miss calculation of the age structure.

  18. Growth parameters and density variation of a queen conch, Strombus gigas (Neotaenioglossa: Strombidae, population from Xel-Ha park, a marine protected area

    Directory of Open Access Journals (Sweden)

    Erick Baqueiro Cárdenas

    2014-03-01

    Full Text Available The queen conch, Strombus gigas, is a gastropod of commercial importance in the Caribbean. Population studies are based on size frequency analysis, using either length or weight parameters for the whole live organism. This contribution used mark-recapture data to estimate the von Bertalanffy equation parameters and population number variation within a non harvest population from a protected area, to clarify the biometric parameters that better suit for the whole population, or for the juvenile and adult fractions. Conchs from Xel- Ha Park were monthly sampled from November 2001 to August 2005. Every conch found was measured and marked with a numbered tag that identified month and locality; and monthly abundance was estimated with Jolly’s method. Length, lip thickness and weight increments were used to estimate the von Bertalanffy growth equation parameters with Appeldoorn’s subroutine of FISAT program. The population number varied through the study, with a minimum of 49 in April 2003 and maximum of 9 848 during June 2005. Conchs make only temporary use of Xel-Ha cove. Shell length gave the best fit for the juvenile fraction: L∞=251, K=0.3, C=0.8 Wp=0.3; and lip thickness for adults: L∞=47.78, K=0.17, C=0.1, Wp=0.86, while, the whole population was bet- ter represented by weight: L∞=3850, K=0.36, C=0.8, Wp=0.3. A maximum age of 19 years was estimated from the population. Natural mortality was 0.49/year for juveniles and 0.29/year for adults. There were two pulses of recruitment: fall-winter and summer. It is concluded that population studies from length frequency data, should be analyzed independently in two groups, shell for the juvenile fraction and lip thickness for the adult fraction, or if it is not possible to analyze the population fractions separately, weight should be used to avoid miss calculation of the age structure.

  19. Electromechanical imitator of antilock braking modes of wheels with pneumatic tire and its application for the runways friction coefficient measurement

    Science.gov (United States)

    Putov, A. V.; Kopichev, M. M.; Ignatiev, K. V.; Putov, V. V.; Stotckaia, A. D.

    2017-01-01

    In this paper it is considered a discussion of the technique that realizes a brand new method of runway friction coefficient measurement based upon the proposed principle of measuring wheel braking control for the imitation of antilock braking modes that are close to the real braking modes of the aircraft chassis while landing that are realized by the aircraft anti-skid systems. Also here is the description of the model of towed measuring device that realizes a new technique of runway friction coefficient measuring, based upon the measuring wheel braking control principle. For increasing the repeatability accuracy of electromechanical braking imitation system the sideslip (brake) adaptive control system is proposed. Based upon the Burkhard model and additive random processes several mathematical models were created that describes the friction coefficient arrangement along the airstrip with different qualitative adjectives. Computer models of friction coefficient measuring were designed and first in the world the research of correlation between the friction coefficient measuring results and shape variations, intensity and cycle frequency of the measuring wheel antilock braking modes. The sketch engineering documentation was designed and prototype of the latest generation measuring device is ready to use. The measuring device was tested on the autonomous electromechanical examination laboratory treadmill bench. The experiments approved effectiveness of method of imitation the antilock braking modes for solving the problem of correlation of the runway friction coefficient measuring.

  20. Small-scale spatial variation in population- and individual-level reproductive parameters of the blue-legged hermit crab Clibanarius tricolor

    Directory of Open Access Journals (Sweden)

    J. Antonio Baeza

    2017-02-01

    Full Text Available Management of the few regulated ornamental fisheries relies on inadequate information about the life history of the target species. Herein, we investigated the reproductive biology of the most heavily traded marine invertebrate in the western Atlantic; the blue-legged hermit crab Clibanarius tricolor. We report on density, individual-level, and population-level reproductive parameters in 14 populations spanning the Florida Keys. In C. tricolor, abundance, population-level, and individual-level reproductive parameters exhibited substantial small-scale spatial variation in the Florida Keys. For instance, the proportion of brooding females varied between 10–94% across localities. In females, average (±SD fecundity varied between 184 (±54 and 614 (±301 embryos crab-1 across populations. Fecundity usually increases with female body size in hermit crabs. However, we found no effect of female body size on fecundity in three of the populations. Altogether, our observations suggest that C. tricolor may fit a source-sink metapopulation dynamic in the Florida Keys with low reproductive intensity and absence of a parental body size—fecundity relationship resulting in net reproductive loses at some localities. We argue in favor of additional studies describing population dynamics and other aspects of the natural history of C. tricolor (e.g., development type, larval duration to reveal ‘source’ populations, capable of exporting larvae to nearby populations. Our observations imply that future studies aimed at assessing standing stocks or describing other aspects of the life history of this hermit crab need to focus on multiple localities simultaneously. This and future studies on the reproductive biology of this species will form the baseline for models aimed at assessing the stock condition and sustainability of this heavily harvested crustacean.

  1. The importance of mechano-electrical feedback and inertia in cardiac electromechanics.

    Science.gov (United States)

    Costabal, Francisco Sahli; Concha, Felipe A; Hurtado, Daniel E; Kuhl, Ellen

    2017-06-15

    In the past years, a number cardiac electromechanics models have been developed to better understand the excitation-contraction behavior of the heart. However, there is no agreement on whether inertial forces play a role in this system. In this study, we assess the influence of mass in electromechanical simulations, using a fully coupled finite element model. We include the effect of mechano-electrical feedback via stretch activated currents. We compare five different models: electrophysiology, electromechanics, electromechanics with mechano-electrical feedback, electromechanics with mass, and electromechanics with mass and mechano-electrical feedback. We simulate normal conduction to study conduction velocity and spiral waves to study fibrillation. During normal conduction, mass in conjunction with mechano-electrical feedback increased the conduction velocity by 8.12% in comparison to the plain electrophysiology case. During the generation of a spiral wave, mass and mechano-electrical feedback generated secondary wavefronts, which were not present in any other model. These secondary wavefronts were initiated in tensile stretch regions that induced electrical currents. We expect that this study will help the research community to better understand the importance of mechanoelectrical feedback and inertia in cardiac electromechanics.

  2. Development of cup-shaped micro-electromechanical systems-based vector hydrophone

    Science.gov (United States)

    Xu, Wei; Liu, Yuan; Zhang, Guojun; Wang, Renxin; Xue, Chenyang; Zhang, Wendong; Liu, Jun

    2016-09-01

    Similar to the vital performance factors, the receiving sensitivity and the bandwidth exist interactively in the micro-electromechanical systems (MEMS)-based vector hydrophones. Some existing methods can improve the sensitivity of the hydrophone, but these improvements are usually gained at a cost of the bandwidth. However, the cup-shaped MEMS vector hydrophone that is presented in this paper can improve its sensitivity while retaining a sufficient bandwidth. The cup-shaped structure acts as a new sensing unit in the MEMS vector hydrophone, replacing the bionic columnar hair that was previously used for sensing. The relationships between the parameters of the cup-shaped structure and the sensitivity of the vector hydrophone were determined by a theoretical deduction. In addition, simulation analyses were performed, and optimized structural parameters were obtained in this work. ANSYS 15.0 simulation was used to derive the optimum characteristics for the cup-shaped structure. The results of the calibration experiments showed that the sensitivity reached up to -188.5 dB (gain of 40 dB, 1 kHz, 0 dB@1 V/μPa), and the bandwidth was in the 20 Hz-1 kHz range, which is sufficient for an underwater acoustic detection at low frequencies. This work has, thus, proved that the cup-shaped vector hydrophone has superior properties for the engineering applications.

  3. The electro-mechanical effect from charge dynamics on polymeric insulation lifetime

    Directory of Open Access Journals (Sweden)

    H. Alghamdi

    2015-12-01

    Full Text Available For polymeric material used as electrical insulation, the presence of space charges could be the consequence of material degradations that are thermally activated but increased by the application of an electric field. The dynamics of space charge, therefore, can be potentially used to characterize the material. In this direction, a new aging model in which parameters have clear physical meanings has been developed and applied to the material to extrapolate the lifetime. The kinetic equation has been established based on charge trapping and detrapping of the injected charge from the electrodes. The local electromechanical energy stored in the region surrounding the trap is able to reduce the trap-depth with a value related to the electric field. At a level where the internal electric field exceeds the detrapping field in the material, an electron can be efficiently detrapped and the released energy from detrapping process can cause a weak bond or chain scission i.e. material degradation. The model has been applied to the electro-thermally aged low density polyethylene film samples, showing well fitted result, as well as interesting relationships between parameter estimates and insulation morphology.

  4. The electro-mechanical effect from charge dynamics on polymeric insulation lifetime

    Energy Technology Data Exchange (ETDEWEB)

    Alghamdi, H., E-mail: haalghamdi@nu.edu.sa [Faculty of Physical Sciences and Engineering, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Faculty of Engineering, Najran University, Najran, P.O.Box 1988 (Saudi Arabia); Chen, G.; Vaughan, A. S. [Faculty of Physical Sciences and Engineering, University of Southampton, Southampton, SO17 1BJ (United Kingdom)

    2015-12-15

    For polymeric material used as electrical insulation, the presence of space charges could be the consequence of material degradations that are thermally activated but increased by the application of an electric field. The dynamics of space charge, therefore, can be potentially used to characterize the material. In this direction, a new aging model in which parameters have clear physical meanings has been developed and applied to the material to extrapolate the lifetime. The kinetic equation has been established based on charge trapping and detrapping of the injected charge from the electrodes. The local electromechanical energy stored in the region surrounding the trap is able to reduce the trap-depth with a value related to the electric field. At a level where the internal electric field exceeds the detrapping field in the material, an electron can be efficiently detrapped and the released energy from detrapping process can cause a weak bond or chain scission i.e. material degradation. The model has been applied to the electro-thermally aged low density polyethylene film samples, showing well fitted result, as well as interesting relationships between parameter estimates and insulation morphology.

  5. Electromechanical actuators affected by multiple failures: Prognostic method based on spectral analysis techniques

    Science.gov (United States)

    Belmonte, D.; Vedova, M. D. L. Dalla; Ferro, C.; Maggiore, P.

    2017-06-01

    The proposal of prognostic algorithms able to identify precursors of incipient failures of primary flight command electromechanical actuators (EMA) is beneficial for the anticipation of the incoming failure: an early and correct interpretation of the failure degradation pattern, in fact, can trig an early alert of the maintenance crew, who can properly schedule the servomechanism replacement. An innovative prognostic model-based approach, able to recognize the EMA progressive degradations before his anomalous behaviors become critical, is proposed: the Fault Detection and Identification (FDI) of the considered incipient failures is performed analyzing proper system operational parameters, able to put in evidence the corresponding degradation path, by means of a numerical algorithm based on spectral analysis techniques. Subsequently, these operational parameters will be correlated with the actual EMA health condition by means of failure maps created by a reference monitoring model-based algorithm. In this work, the proposed method has been tested in case of EMA affected by combined progressive failures: in particular, partial stator single phase turn to turn short-circuit and rotor static eccentricity are considered. In order to evaluate the prognostic method, a numerical test-bench has been conceived. Results show that the method exhibit adequate robustness and a high degree of confidence in the ability to early identify an eventual malfunctioning, minimizing the risk of fake alarms or unannounced failures.

  6. Seasonal variation in coat characteristics, tick loads, cortisol levels, some physiological parameters and temperature humidity index on Nguni cows raised in low- and high-input farms.

    Science.gov (United States)

    Katiyatiya, C L F; Muchenje, V; Mushunje, A

    2015-06-01

    Seasonal variations in hair length, tick loads, cortisol levels, haematological parameters (HP) and temperature humidity index (THI) in Nguni cows of different colours raised in two low-input farms, and a commercial stud was determined. The sites were chosen based on their production systems, climatic characteristics and geographical locations. Zazulwana and Komga are low-input, humid-coastal areas, while Honeydale is a high-input, dry-inland Nguni stud farm. A total of 103 cows, grouped according to parity, location and coat colour, were used in the study. The effects of location, coat colour, hair length and season were used to determine tick loads on different body parts, cortisol levels and HP in blood from Nguni cows. Highest tick loads were recorded under the tail and the lowest on the head of each of the animals (P cows recorded the highest tick loads under the tails of all the cows used in the study from the three farms (P tick loads were recorded for cows with long hairs. Hair lengths were longest during the winter season in the coastal areas of Zazulwana and Honeydale (P cows had significantly longer (P tick loads on different body parts and heat stress in Nguni cows.

  7. Model for biomass char combustion in the riser of a dual fluidized bed gasification unit: Part II - model validation and parameter variation

    Energy Technology Data Exchange (ETDEWEB)

    Kaushal, Priyanka; Proell, Tobias; Hofbauer, Hermann [Vienna University of Technology, Institute of Chemical Engineering, Getreidemarkt 9/166, A-1060, Vienna (Austria)

    2008-07-15

    The two-phase combustion model for biomass char combustion in a riser of a dual fluidized bed gasification unit that has been presented in part I is validated using the data obtained from the 8 MWth dual fluidized bed reactor at Guessing/Austria. The model is capable of calculating the average temperatures in all zones, the gas phase composition, solid hold up, char feed rates and air ratio. The model predictions for the temperature profile along the riser and for the exiting gas composition are in good agreement with the measured values. The simulation results show that the residual char from the gasifier is only partly converted in the riser for char particles larger than 0.6 mm. Un-combusted char is circulated back into the gasification reactor. Parameter variations show that the exact location where additional liquid fuels are introduced in the middle zone of the riser does not affect the global behaviour of the combustion reactor. Based on the simulation results it is proposed that external supply of char (additional) may be a very effective method for reducing producer gas recycling to the riser, which is currently necessary to obtain the desired gasification temperatures. (author)

  8. Evaluation of the seasonal variation on the geochemical parameters and quality assessment of the groundwater in the proximity of River Cooum, Chennai, India.

    Science.gov (United States)

    Giridharan, L; Venugopal, T; Jayaprakash, M

    2008-08-01

    The seasonal variations of the chemical budget of ions were determined from the hydrochemical investigation of the groundwater. Though the effect of monsoon does not change the order of abundance of cations, but it does change the concentration of various ions and it is found that there was a considerable change in the case of all major ions. The unique characteristic of the ground water is the linear relationship among the principal ions. Hydrochemical characteristics of ions in the groundwater were studied using 1:1 equiline diagrams. The nature of the water samples were determined using the piper diagram. The correlation studies and R-mode factor analysis were carried out on the various groundwater parameters. The study of factor scores reveals the extent of influence of each factors on the overall water chemistry at each sampling stations. The trace metal concentration in the water was determined. The quality of the groundwater in the study area has been assessed using Percent sodium, SAR and Wilcox diagrams. The groundwater results of the premonsoon shows the dominance of excessive evaporation, silicate weathering and anthropogenic activities whereas in postmonsoon, dilution predominates over that of other factors.

  9. Seasonal variation in coat characteristics, tick loads, cortisol levels, some physiological parameters and temperature humidity index on Nguni cows raised in low- and high-input farms

    Science.gov (United States)

    Katiyatiya, C. L. F.; Muchenje, V.; Mushunje, A.

    2015-06-01

    Seasonal variations in hair length, tick loads, cortisol levels, haematological parameters (HP) and temperature humidity index (THI) in Nguni cows of different colours raised in two low-input farms, and a commercial stud was determined. The sites were chosen based on their production systems, climatic characteristics and geographical locations. Zazulwana and Komga are low-input, humid-coastal areas, while Honeydale is a high-input, dry-inland Nguni stud farm. A total of 103 cows, grouped according to parity, location and coat colour, were used in the study. The effects of location, coat colour, hair length and season were used to determine tick loads on different body parts, cortisol levels and HP in blood from Nguni cows. Highest tick loads were recorded under the tail and the lowest on the head of each of the animals ( P Cortisol and THI were significantly lower ( P cortisol levels, THI, HP and tick loads on different body parts and heat stress in Nguni cows.

  10. Estuarine Turbidity Maxima and Variations of Aggregate Parameters in the Cam-Nam Trieu Estuary, North Vietnam, in Early Wet Season

    Directory of Open Access Journals (Sweden)

    Vu Duy Vinh

    2018-01-01

    Full Text Available This study aims at exploring the characteristic parameters of the Estuarine Turbidity Maxima (ETM and at investigating their tidal variations within the Cam-Nam Trieu estuary (North Vietnam during the early wet season. Six longitudinal river transects were performed at spring tide. Two types of ETM were observed: an upper well mixed ETM with high Suspended Particulate Matter (SPM concentrations up to the surface at low salinity (0.11 to <1 psu, and a lower ETM confined in a bottom layer over stratified waters at salinities between ~1 psu and 15 psu. Their length depended on the longitudinal salinity gradient and was highest at low tide than at high tide. D50 of the flocs varied between 35 and 90 μm, their excess of density between 60 and 300 kg m−3 and their settling velocity ranged from 0.07 to 0.55 mm s−1 with values between 0.12 and 0.40 mm s−1 in the core of ETMs. The average fractal dimension of flocs was estimated to vary between 1.93 (at high tide to 2.04 (at low tide.

  11. Associations between annual and seasonal variations in body mass and reproductive success and blood biochemical parameters in semi-domesticated reindeer

    Directory of Open Access Journals (Sweden)

    Ingrid H. Holmøy

    2009-12-01

    Full Text Available The main objective of the study was to follow reproductive performance and blood biochemical parameters associated with fat and carbohydrate metabolism in a herd of free-ranging, semi-domesticated reindeer (Rangifer tarandus tarandus over a two-year period, with extreme between-year variation in forage availability. The effects of climatic factors on reindeer reproductive performance were investigated by analysing whether time of onset of luteal function in autumn and calf survival were associated with changes in body mass and weather conditions, such as snow depth, precipitation, and temperature. Considerable between-year variation in the onset of luteal activity was found. In 1997, 4.2% of the female reindeer were either cycling or pregnant in the second week of October, whilst in 1998, in the same week, 100% were cycling or pregnant. Although energy balance was important for timing of the onset of luteal activity, delayed conception had no apparent effect on calf survival. The results indicated that maternal body mass (BM in spring was of primary importance for calf survival, and the productivity of the herd. Since climatic factors influence the availability of forage, and hence female BM, it also has an indirect impact on calf survival. Females with low BM demonstrated greater seasonal variation in BM than heavier females. Plasma concentrations of free fatty acids and β-hydroxy butyric acid responded to changes in forage availability, but the initial condition of the reindeer and their fat reserves also seemed to have a major influence on these parameters.Abstract in Norwegian / Sammendrag:Sammenheng mellom års- og sesongvariasjon i kroppsvekt og henholdsvis reproduksjonssuksess og biokjemiske blodparametre hos tamreinHovedformålet med studien var å følge reproduksjonen og blodparametre knyttet til fett og karbohydratmetabolismen hos en tamreinflokk (Rangifer tarandus tarandus gjennom en toårs periode med stor årlig variasjon i n

  12. Valve position tracking for soft landing of electromechanical camless valvetrain

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, W. [Siemens AG, Erlangen (Germany); Stefanopoulou, A.G. [University of Michigan, Ann Arbor, MI (United States). Dept. of Mechanical Engineering

    2001-07-01

    Variable valve opening and closing allows improvements of internal combustion engines and requires precise control of the camless valvetrain actuator. In this paper the valve position tracking in electromechanical camless valvetrains (EMCV) is considered. One of the main problems in the EMCV actuator is the noise and wear associated with high contact velocities during the closing and opening of the valve. The contact velocity of the actuator and the valve can be reduced, and thus, noise and wear, by designing a tracking controller that consists of a linear feedback and an iterative learning controller (ILC). With the ILC methodology every cycle the feedforward signal of the feedback controller is updated based on the error between the actual valve position and the desired position. The methodology is reviewed and simulation results are presented. (author)

  13. Valve position tracking for soft landing of electromechanical camless valvetrain

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, W. [Siemens AG, Erlangen (Germany); Stefanopoulou, A.G. [Michigan Univ., Ann Arbor, MI (United States). Dept. of Mechanical Engineering

    2001-07-01

    Variable valve opening and closing allows improvements of internal combustion engines and requires precise control of the camless valvetrain actuator. In this paper the valve position tracking in electromechanical camless valvetrains (EMCV) is considered. One of the main problems in the EMCV actuator is the noise and wear associated with high contact velocities during the closing and opening of the valve. The contact velocity of the actuator and the valve can be reduced, and thus, noise and wear, by designing a tracking controller that consists of a linear feedback and an iterative learning controller (ILC). With the ILC methodology every cycle the feedforward signal of the feedback controller is updated based on the error between the actual valve position and the desired position. The methodology is reviewed and simulation results are presented. (orig.)

  14. Evaluation of the electromechanical properties of the cardiovascular system

    Science.gov (United States)

    Bergman, S. A., Jr.; Hoffler, G. W.; Johnson, R. L.

    1974-01-01

    Cardiovascular electromechanical measurements were collected on returning Skylab crewmembers at rest and during both lower body negative pressure and exercise stress testing. These data were compared with averaged responses from multiple preflight tests. Systolic time intervals and first heart sound amplitude changes were measured. Clinical cardiovascular examinations and clinical phonocardiograms were evaluated. All changes noted returned to normal within 30 days postflight so that the processes appear to be transient and self limited. The cardiovascular system seems to adapt quite readily to zero-g, and more importantly it is capable of readaptation to one-g after long duration space flight. Repeated exposures to zero-g also appear to have no detrimental effects on the cardiovascular system.

  15. An electromechanical, patient positioning system for head and neck radiotherapy

    Science.gov (United States)

    Ostyn, Mark; Dwyer, Thomas; Miller, Matthew; King, Paden; Sacks, Rachel; Cruikshank, Ross; Rosario, Melvin; Martinez, Daniel; Kim, Siyong; Yeo, Woon-Hong

    2017-09-01

    In cancer treatment with radiation, accurate patient setup is critical for proper dose delivery. Improper arrangement can lead to disease recurrence, permanent organ damage, or lack of disease control. While current immobilization equipment often helps for patient positioning, manual adjustment is required, involving iterative, time-consuming steps. Here, we present an electromechanical robotic system for improving patient setup in radiotherapy, specifically targeting head and neck cancer. This positioning system offers six degrees of freedom for a variety of applications in radiation oncology. An analytical calculation of inverse kinematics serves as fundamental criteria to design the system. Computational mechanical modeling and experimental study of radiotherapy compatibility and x-ray-based imaging demonstrates the device feasibility and reliability to be used in radiotherapy. An absolute positioning accuracy test in a clinical treatment room supports the clinical feasibility of the system.

  16. Flywheel for an electro-mechanical fastener driving tool

    Energy Technology Data Exchange (ETDEWEB)

    Crutcher, J. P.

    1985-05-28

    An improved flywheel for an electro-mechanical tool, such as a nailer or stapler. The tool is of the type provided with a driver which is frictionally moved through a working stroke by means of an electrically driven flywheel which presses the driver against a support element, such as a counterrotating flywheel, a low inertia roller, or the like. The flywheel is provided with circumferential grooves while maintaining the optimum contact area between the flywheel and the driver. The grooves provide voids along the travelling driver-flywheel contact line into which foreign material on the driver and flywheel flows to prevent build-up of such foreign material at the driver-flywheel contact area sufficient to result in loss of friction therebetween.

  17. Qubit Coupled Mechanical Resonator in an Electromechanical System

    Science.gov (United States)

    Hao, Yu

    This thesis describes the development of a hybrid quantum electromechanical system. In this system the mechanical resonator is capacitively coupled to a superconducting transmon which is embedded in a superconducting coplanar waveguide (CPW) cavity. The difficulty of achieving high quality of superconducting qubit in a high-quality voltage-biased cavity is overcome by integrating a superconducting reflective T-filter to the cavity. Further spectroscopic and pulsed measurements of the hybrid system demonstrate interactions between the ultra-high frequency mechanical resonator and transmon qubit. The noise of mechanical resonator close to ground state is measured by looking at the spectroscopy of the transmon. At last, fabrication and tests of membrane resonators are discussed.

  18. Electron-electron attraction in an engineered electromechanical system

    Science.gov (United States)

    Széchenyi, Gábor; Pályi, András; Droth, Matthias

    2017-12-01

    Two electrons in a quantum dot repel each other: their interaction can be characterized by a positive interaction energy. From the theory of superconductivity, we also know that mechanical vibrations of the crystal lattice can make the electron-electron interaction attractive. Analogously, if a quantum dot interacts with a mechanical degree of freedom, the effective interaction energy can be negative; that is, the electron-electron interaction might be attractive. In this work, we propose and theoretically study an engineered electromechanical system that exhibits electron-electron attraction: a quantum dot suspended on a nonlinear mechanical resonator, tuned by a bottom and a top gate electrode. We focus on the example of a dot embedded in a suspended graphene ribbon, for which we identify conditions for electron-electron attraction. Our results suggest the possibility of electronic transport via tunneling of packets of multiple electrons in such devices, similar to that in superconducting nanostructures, but without the use of any superconducting elements.

  19. Sub-kBT micro-electromechanical irreversible logic gate.

    Science.gov (United States)

    López-Suárez, M; Neri, I; Gammaitoni, L

    2016-06-28

    In modern computers, computation is performed by assembling together sets of logic gates. Popular gates like AND, OR and XOR, processing two logic inputs and yielding one logic output, are often addressed as irreversible logic gates, where the sole knowledge of the output logic value is not sufficient to infer the logic value of the two inputs. Such gates are usually believed to be bounded to dissipate a finite minimum amount of energy determined by the input-output information difference. Here we show that this is not necessarily the case, by presenting an experiment where a OR logic gate, realized with a micro-electromechanical cantilever, is operated with energy well below the expected limit, provided the operation is slow enough and frictional phenomena are properly addressed.

  20. Crack detection in pipelines using multiple electromechanical impedance sensors

    Science.gov (United States)

    Zuo, Chunyuan; Feng, Xin; Zhang, Yu; Lu, Lu; Zhou, Jing

    2017-10-01

    An extensive network of pipeline systems is used to transport and distribute national energy resources that heavily influence a nation’s economy. Therefore, the structural integrity of these pipeline systems must be monitored and maintained. However, structural damage detection remains a challenge in pipeline engineering. To this end, this study developed a modified electromechanical impedance (EMI) technique for crack detection that involves fusing information from multiple sensors. We derived a new damage-sensitive feature factor based on a pipeline EMI model that considers the influence of the bonding layer between the EMI sensors and pipeline. We experimentally validated the effectiveness of the proposed method. Finally, we used a damage index—root mean square deviation—to examine the degree and position of crack damage in a pipeline.

  1. The electro-mechanical behaviour of flexural ultrasonic transducers

    Science.gov (United States)

    Dixon, Steve; Kang, Lei; Ginestier, Michael; Wells, Christopher; Rowlands, George; Feeney, Andrew

    2017-05-01

    Flexural ultrasonic transducers are capable of high electro-mechanical coupling efficiencies for the generation or detection of ultrasound in fluids. They are the most common type of ultrasonic sensor, commonly used in parking sensors, because the devices are efficient, robust, and inexpensive. The simplest design consists of a piezoelectric disc, bonded to the inner surface of a metal cap, the face of which provides a vibrating membrane for the generation or detection of ultrasonic waves in fluids. Experimental measurements demonstrate that during the excitation of the piezoelectric element by an electrical voltage, there are three characteristic regions, where the frequency of the emitted ultrasonic wave changes during the excitation, steady-state, and the final decay process. A simple mechanical analogue model is capable of describing this behaviour.

  2. Optomechanical effects of two-level states in electromechanical devices

    Science.gov (United States)

    Suh, Junho; Weinstein, Aaron; Schwab, Keith

    2013-03-01

    It is now clearly established that the presence of two-level states can act as a power-dependent dielectric and lead to non-linear response of lithographic superconducting circuits. We observe these effects in a parametrically coupled, superconducting electro-mechanical system. In this case, the driven two-level states shift the microwave resonance frequency, and modulate the mechanical resonance through the optical spring effect. When pumping with two tones to realize a back-action evading measurement, these effects produce mechanical frequency modulation at twice the mechanical resonance, leading to a parametric instability for strong drives sufficient to produce a single quadrature measurement near the zero-point level. We also discuss schemes to avoid these effects in future devices.

  3. Development and field tests of a damping controller to mitigate electromechanical oscillations on large diesel generating units

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, Fabricio G.; Barreiros, Jose A.L.; Barra, Walter Jr.; Costa, Carlos T. Jr. [Universidade Federal do Para (UFPA), Instituto de Tecnologia, Faculdade de Engenharia Eletrica, Campus Universitario do Guama, CEP: 66075-900, Belem (Brazil); Ferreira, Andre M.D. [Instituto Federal de Educacao, Ciencia e Tecnologia do Para (IFPA), Campus Belem, Departamento de Controle e Processos Industriais, Av. Almirante Barroso, 1155 (Marco), CEP: 66093-020, Belem (Brazil)

    2011-02-15

    This paper presents the development and field tests of a digital damping controller designed to mitigate intra-plant electromechanical oscillations via the speed governor system of fast acting units. The controller performance is assessed on an 18-MVA diesel generating unit, at Santana Power Plant (Amapa State, Amazon Region at Northern Brazil). In order to design the damping control law, a set of parametric ARX models representing the plant dynamics at several load conditions, are previously identified from data collected on field tests. The damping controller gains are calculated by using the identified ARX models parameters as inputs to a discrete-time pole-placement design method (pole-shifting) and then embedded on a DSP based microcontroller digital system, for field tests assessment. The digital damping controller modulates the diesel engine inlet valve position according to the observed oscillation on the measured electric power, using a PWM device, which is specially developed to this application. The experimental results shown the good performance of the developed controller on damping efficiently the electromechanical oscillations observed between generating units at Santana Power Plant. (author)

  4. Mathematical Modelling and Parameter Identification of an Electro-Magneto-Mechanical Actuator for Vibration Control

    DEFF Research Database (Denmark)

    Darula, Radoslav; Stein, George Juraj; Kallesøe, Carsten Skovmose

    2012-01-01

    Electromechanical systems for vibration control exhibit complex non-linear behaviour. Therefore advanced mathematical tools and appropriate simplifications are required for their modelling. To properly understand the dynamics of such a non-linear system, it is necessary to identify the parameters...... of the electromagnetic circuit in its various operational regimes. The parametric identification supplements mathematical derivations. The analyzed mechanical system is essentially a Single Degree-Of-Freedom (SDOF) oscillatory system augmented by magnetic force influence. The additional magnetic force is generated...... by an electromagnet with armature. The electromagnet is energized by a constant voltage source. The SDOF system is excited by a harmonic force causing vibration of the armature. Due to the reluctance variation of the air gap of the magnetic circuit alternating voltage is generated across the coil terminals...

  5. Micro-electromechanical film bulk acoustic sensor for plasma and whole blood coagulation monitoring.

    Science.gov (United States)

    Chen, Da; Song, Shuren; Ma, Jilong; Zhang, Zhen; Wang, Peng; Liu, Weihui; Guo, Qiuquan

    2017-05-15

    Monitoring blood coagulation is an important issue in the surgeries and the treatment of cardiovascular diseases. In this work, we reported a novel strategy for the blood coagulation monitoring based on a micro-electromechanical film bulk acoustic resonator. The resonator was excited by a lateral electric field and operated under the shear mode with a frequency of 1.9GHz. According to the apparent step-ladder curves of the frequency response to the change of blood viscoelasticity, the coagulation time (prothrombin time) and the coagulation kinetics were measured with the sample consumption of only 1μl. The procoagulant activity of thromboplastin and the anticoagulant effect of heparin on the blood coagulation process were illustrated exemplarily. The measured prothrombin times showed a good linear correlation with R2=0.99969 and a consistency with the coefficient of variation less than 5% compared with the commercial coagulometer. The proposed film bulk acoustic sensor, which has the advantages of small size, light weight, low cost, simple operation and little sample consumption, is a promising device for miniaturized, online and automated analytical system for routine diagnostics of hemostatic status and personal health monitoring. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Variation of kQclin,Qmsr (fclin,fmsr) for the small-field dosimetric parameters percentage depth dose, tissue-maximum ratio, and off-axis ratio.

    Science.gov (United States)

    Francescon, Paolo; Beddar, Sam; Satariano, Ninfa; Das, Indra J

    2014-10-01

    Evaluate the ability of different dosimeters to correctly measure the dosimetric parameters percentage depth dose (PDD), tissue-maximum ratio (TMR), and off-axis ratio (OAR) in water for small fields. Monte Carlo (MC) simulations were used to estimate the variation of kQclin,Qmsr (fclin,fmsr) for several types of microdetectors as a function of depth and distance from the central axis for PDD, TMR, and OAR measurements. The variation of kQclin,Qmsr (fclin,fmsr) enables one to evaluate the ability of a detector to reproduce the PDD, TMR, and OAR in water and consequently determine whether it is necessary to apply correction factors. The correctness of the simulations was verified by assessing the ratios between the PDDs and OARs of 5- and 25-mm circular collimators used with a linear accelerator measured with two different types of dosimeters (the PTW 60012 diode and PTW PinPoint 31014 microchamber) and the PDDs and the OARs measured with the Exradin W1 plastic scintillator detector (PSD) and comparing those ratios with the corresponding ratios predicted by the MC simulations. MC simulations reproduced results with acceptable accuracy compared to the experimental results; therefore, MC simulations can be used to successfully predict the behavior of different dosimeters in small fields. The Exradin W1 PSD was the only dosimeter that reproduced the PDDs, TMRs, and OARs in water with high accuracy. With the exception of the EDGE diode, the stereotactic diodes reproduced the PDDs and the TMRs in water with a systematic error of less than 2% at depths of up to 25 cm; however, they produced OAR values that were significantly different from those in water, especially in the tail region (lower than 20% in some cases). The microchambers could be used for PDD measurements for fields greater than those produced using a 10-mm collimator. However, with the detector stem parallel to the beam axis, the microchambers could be used for TMR measurements for all field sizes. The

  7. Low-power feedback-enhanced electro-mechanical impedance (FEMI) sensors

    Science.gov (United States)

    Jang, Ji Eun; Yue, C. Patrick

    2008-03-01

    Electro-mechanical impedance (EMI) method utilizing smart piezoelectric sensors has emerged as a promising technology for structural health monitoring in civil, mechanical and aerospace engineering. However, two major limiting factors have prevented field deployment of this method in real life. First, smart piezoelectric sensors, such as Lead Zirconate Titanate (PZT) patches, are highly sensitive to environmental changes such as temperature, humidity, and vibration. Secondly, bulky and expensive equipment is needed for performing impedance measurement. This paper proposes a feedback-enhanced electro-mechanical impedance (FEMI) technique for improving robustness against environmental variations and a design of a low-power EMI sensor with built-in measurement circuitries based on this new technique. The proposed FEMI technique employs a feedback scheme to amplify the peaking characteristics of the natural resonance frequencies in the EMI frequency response. The feedback loop includes a phase-locked loop (PLL) and a transimpedance amplifier (TIA). An analog EMI measurement circuit is developed to replace bulky EMI measurement instruments. To keep the power consumption low, the proposed system does not require any analog-to-digital conversion or DSP circuit blocks, but uses a simple analog mixer to multiply input and output waveforms of the PZT sensor, and then extract the EMI amplitude by passing the mixer output through a low-pass filter (LPF). The performance of the proposed FEMI sensor is verified by simulations using MATLAB. Simulated natural frequency peaks in the EMI spectrum are noticeably sharper with the feedback scheme than the one without feedback. As a result, the natural frequency shift due to any structural change can be more easily detected. To quantify the shift of these natural frequency peaks, the root mean square deviation (RMSD) of the difference between cases with and without damage is calculated. The simulation results show that the RMSD with

  8. A Diagnostic Approach for Electro-Mechanical Actuators in Aerospace Systems

    Data.gov (United States)

    National Aeronautics and Space Administration — Electro-mechanical actuators (EMA) are finding increasing use in aerospace applications, especially with the trend towards all all-electric aircraft and spacecraft...

  9. Experimental and Analytical Development of a Health Management System for Electro-Mechanical Actuators

    Data.gov (United States)

    National Aeronautics and Space Administration — Expanded deployment of Electro-Mechanical Actuators (EMAs) in critical applications has created much interest in EMA Prognostic Health Management (PHM), a key...

  10. Piezoelectric Tailoring with Enhanced Electromechanical Coupling for Concurrent Vibration Control of Mistuned Periodic Structures

    National Research Council Canada - National Science Library

    Wang, Kon-Well

    2006-01-01

    The objective of this research is to advance the state of the art of vibration control of mistuned periodic structures utilizing the electromechanical coupling and damping characteristics of piezoelectric networking...

  11. Experimental Validation of a Prognostic Health Management System for Electro-Mechanical Actuators

    Data.gov (United States)

    National Aeronautics and Space Administration — The work described herein is aimed to advance prognostic health management solutions for electro-mechanical actuators and, thus, increase their reliability and...

  12. ENGAGEMENT SLIP CONTROLLER DEVELOPMENT BASED ON ACTUATOR DISPLACEMENT FOR AN ELECTRO-MECHANICAL FRICTION CLUTCH SYSTEM

    National Research Council Canada - National Science Library

    M S Che Kob; B Supriyo; K B Tawi; I I Mazali

    2015-01-01

    ...) controller algorithm to engage the dry friction clutch. The EMFC is electro-mechanically actuated using a DC motor system, such that a smooth engagement process can be performed satisfactorily...

  13. Experimental Data Collection and Modeling for Nominal and Fault Conditions on Electro-Mechanical Actuators

    Data.gov (United States)

    National Aeronautics and Space Administration — Being relatively new to the field, electromechanical actuators in aerospace applications lack the knowledge base compared to ones accumulated for the other actuator...

  14. Shell-binary nanoparticle materials with variable electrical and electro-mechanical properties.

    Science.gov (United States)

    Zhang, P; Bousack, H; Dai, Y; Offenhäusser, A; Mayer, D

    2018-01-18

    Nanoparticle (NP) materials with the capability to adjust their electrical and electro-mechanical properties facilitate applications in strain sensing technology. Traditional NP materials based on single component NPs lack a systematic and effective means of tuning their electrical and electro-mechanical properties. Here, we report on a new type of shell-binary NP material fabricated by self-assembly with either homogeneous or heterogeneous arrangements of NPs. Variable electrical and electro-mechanical properties were obtained for both materials. We show that the electrical and electro-mechanical properties of these shell-binary NP materials are highly tunable and strongly affected by the NP species as well as their corresponding volume fraction ratio. The conductivity and the gauge factor of these shell-binary NP materials can be altered by about five and two orders of magnitude, respectively. These shell-binary NP materials with different arrangements of NPs also demonstrate different volume fraction dependent electro-mechanical properties. The shell-binary NP materials with a heterogeneous arrangement of NPs exhibit a peaking of the sensitivity at medium mixing ratios, which arises from the aggregation induced local strain enhancement. Studies on the electron transport regimes and micro-morphologies of these shell-binary NP materials revealed the different mechanisms accounting for the variable electrical and electro-mechanical properties. A model based on effective medium theory is used to describe the electrical and electro-mechanical properties of such shell-binary nanomaterials and shows an excellent match with experiment data. These shell-binary NP materials possess great potential applications in high-performance strain sensing technology due to their variable electrical and electro-mechanical properties.

  15. Modernization of the Grinding Electromechanical Drive System of the Automated Coffee Machine

    Directory of Open Access Journals (Sweden)

    Ilie Nuca

    2014-09-01

    Full Text Available The paper refers to espresso coffee machines high quality and some possibilities to increase the level of automation and productivity. Existing machines require manual adjustment of coffee grinder depending on the quality of coffee beans. To eliminate this flaw has been developed and implemented an adjustable electromechanical system with DC servomotor and numerical control of coffee grinder. Computer simulation results demonstrate the functionality of the proposed electromechanical drive system of the coffee grinder

  16. Electromechanical Battery EMB Mass Minimization taking into Account its Electrical Machines Rotor Energy

    OpenAIRE

    Podgornovs Andrejs; Sipovichs Antons

    2014-01-01

    In this paper the electromechanical battery (EMB) with synchronous machine is described. Theoretically, if electrical machines rotor stored energy is known, it is possible to reduce the flywheel mass of electromechanical battery. For example, the efficiency of energy recovery (kilowatt-hours out versus kilowatthours in) in nowadays appliances exceeds 95 % which is considerably better than of any electrochemical battery, such as lead-acid battery. For the rotor stored energy amount calculation...

  17. An analysis of sensitivity of CLIMEX parameters in mapping species potential distribution and the broad-scale changes observed with minor variations in parameters values: an investigation using open-field Solanum lycopersicum and Neoleucinodes elegantalis as an example

    Science.gov (United States)

    da Silva, Ricardo Siqueira; Kumar, Lalit; Shabani, Farzin; Picanço, Marcelo Coutinho

    2017-02-01

    A sensitivity analysis can categorize levels of parameter influence on a model's output. Identifying parameters having the most influence facilitates establishing the best values for parameters of models, providing useful implications in species modelling of crops and associated insect pests. The aim of this study was to quantify the response of species models through a CLIMEX sensitivity analysis. Using open-field Solanum lycopersicum and Neoleucinodes elegantalis distribution records, and 17 fitting parameters, including growth and stress parameters, comparisons were made in model performance by altering one parameter value at a time, in comparison to the best-fit parameter values. Parameters that were found to have a greater effect on the model results are termed "sensitive". Through the use of two species, we show that even when the Ecoclimatic Index has a major change through upward or downward parameter value alterations, the effect on the species is dependent on the selection of suitability categories and regions of modelling. Two parameters were shown to have the greatest sensitivity, dependent on the suitability categories of each species in the study. Results enhance user understanding of which climatic factors had a greater impact on both species distributions in our model, in terms of suitability categories and areas, when parameter values were perturbed by higher or lower values, compared to the best-fit parameter values. Thus, the sensitivity analyses have the potential to provide additional information for end users, in terms of improving management, by identifying the climatic variables that are most sensitive.

  18. Analytical one parameter method for PID motion controller settings

    NARCIS (Netherlands)

    van Dijk, Johannes; Aarts, Ronald G.K.M.

    2012-01-01

    In this paper analytical expressions for PID-controllers settings for electromechanical motion systems are presented. It will be shown that by an adequate frequency domain oriented parametrization, the parameters of a PID-controller are analytically dependent on one variable only, the cross-over

  19. Effect of the Matching Circuit on the Electromechanical Characteristics of Sandwiched Piezoelectric Transducers.

    Science.gov (United States)

    Lin, Shuyu; Xu, Jie

    2017-02-10

    The input electrical impedance behaves as a capacitive when a piezoelectric transducer is excited near its resonance frequency. In order to increase the energy transmission efficiency, a series or parallel inductor should be used to compensate the capacitive impedance of the piezoelectric transducer. In this paper, the effect of the series matching inductor on the electromechanical characteristics of the piezoelectric transducer is analyzed. The dependency of the resonance/anti-resonance frequency, the effective electromechanical coupling coefficient, the electrical quality factor and the electro-acoustical efficiency on the matching inductor is obtained. It is shown that apart from compensating the capacitive impedance of the piezoelectric transducer, the series matching inductor can also change the electromechanical characteristics of the piezoelectric transducer. When series matching inductor is increased, the resonance frequency is decreased and the anti-resonance unchanged; the effective electromechanical coupling coefficient is increased. For the electrical quality factor and the electroacoustic efficiency, the dependency on the matching inductor is different when the transducer is operated at the resonance and the anti-resonance frequency. The electromechanical characteristics of the piezoelectric transducer with series matching inductor are measured. It is shown that the theoretically predicted relationship between the electromechanical characteristics and the series matching inductor is in good agreement with the experimental results.

  20. Alternative parameter determination methods for a PMSG

    DEFF Research Database (Denmark)

    Kalogiannis, Theodoros; Malz, Elena; Llano, Enrique Muller

    2014-01-01

    One of the fundamental requirements for testing and analysing a Permanent Magnet Synchronous Generator (PMSG) is to obtain its electrical and mechanical parameters. This paper describes the test set up and the procedure for obtaining them. Stator resistance and flux linkage measurements follow IEEE...... the obtained values, an electromechanical model is derived for validation and contribution of the whole project. Finally, small relative errors between measured and simulated values indicate the functionality of the used methods and of the machine....

  1. Electro-mechanical vibration analysis of functionally graded piezoelectric porous plates in the translation state

    Science.gov (United States)

    Wang, Yan Qing

    2018-02-01

    To provide reference for aerospace structural design, electro-mechanical vibrations of functionally graded piezoelectric material (FGPM) plates carrying porosities in the translation state are investigated. A modified power law formulation is employed to depict the material properties of the plates in the thickness direction. Three terms of inertial forces are taken into account due to the translation of plates. The geometrical nonlinearity is considered by adopting the von Kármán non-linear relations. Using the d'Alembert's principle, the nonlinear governing equation of the out-of-plane motion of the plates is derived. The equation is further discretized to a system of ordinary differential equations using the Galerkin method, which are subsequently solved via the harmonic balance method. Then, the approximate analytical results are validated by utilizing the adaptive step-size fourth-order Runge-Kutta technique. Additionally, the stability of the steady state responses is examined by means of the perturbation technique. Linear and nonlinear vibration analyses are both carried out and results display some interesting dynamic phenomenon for translational porous FGPM plates. Parametric study shows that the vibration characteristics of the present inhomogeneous structure depend on several key physical parameters.

  2. Electromechanical Characterization and Locomotion Control of IPMC BioMicroRobot

    Directory of Open Access Journals (Sweden)

    Martin J.-D. Otis

    2013-01-01

    Full Text Available This paper presents the electromechanical characterization of Nafion-Pt microlegs for the development of an insect-like hexapod BioMicroRobot (BMR. BMR microlegs are built using quasi-cylindrical Nafion-Pt ionomeric polymer-metal composite (IPMC, which has 2.5 degrees of freedom. The specific manufacturing process using a laser excimer for one leg in three-dimensional configurations is discussed. Dynamic behavior and microleg characteristics have been measured in deionized water using a laser vibrometer. The use of the laser vibrometer shows the linear characteristics between the duty cycle of square wave input and displacement rate of the actuator at multiple frequencies. This linearity is used to design a servo-system in order to reproduce insect tripod walking. As well, BMR current consumption is an important parameter evaluated for each leg. Current passing throughout the IPMC membrane can result in water electrolysis. Four methods are explained for avoiding electrolysis. The hardware test bench for measurements is presented. The purpose of this design is to control a BMR for biomedical goals such as implantation into a human body. Experimental results for the proposed propulsion system are conclusive for this type of bioinspired BMR.

  3. An Improved Lumped Parameter Model for a Piezoelectric Energy Harvester in Transverse Vibration

    Directory of Open Access Journals (Sweden)

    Guang-qing Wang

    2014-01-01

    Full Text Available An improved lumped parameter model (ILPM is proposed which predicts the output characteristics of a piezoelectric vibration energy harvester (PVEH. A correction factor is derived for improving the precisions of lumped parameter models for transverse vibration, by considering the dynamic mode shape and the strain distribution of the PVEH. For a tip mass, variations of the correction factor with PVEH length are presented with curve fitting from numerical solutions. The improved governing motion equations and exact analytical solution of the PVEH excited by persistent base motions are developed. Steady-state electrical and mechanical response expressions are derived for arbitrary frequency excitations. Effects of the structural parameters on the electromechanical outputs of the PVEH and important characteristics of the PVEH, such as short-circuit and open-circuit behaviors, are analyzed numerically in detail. Accuracy of the output performances of the ILPM is identified from the available lumped parameter models and the coupled distributed parameter model. Good agreement is found between the analytical results of the ILPM and the coupled distributed parameter model. The results demonstrate the feasibility of the ILPM as a simple and effective means for enhancing the predictions of the PVEH.

  4. Electromechanical and robot-assisted arm training for improving activities of daily living, arm function, and arm muscle strength after stroke.

    Science.gov (United States)

    Mehrholz, Jan; Pohl, Marcus; Platz, Thomas; Kugler, Joachim; Elsner, Bernhard

    2015-11-07

    -quality evidence, and adverse events were rare. People who receive electromechanical and robot-assisted arm and hand training after stroke might improve their activities of daily living, arm and hand function, and arm and hand muscle strength. However, the results must be interpreted with caution because the quality of the evidence was low to very low, and there were variations between the trials in the intensity, duration, and amount of training; type of treatment; and participant characteristics.

  5. Beam’s-eye-view dosimetrics (BEVD) guided rotational station parameter optimized radiation therapy (SPORT) planning based on reweighted total-variation minimization

    Science.gov (United States)

    Kim, Hojin; Li, Ruijiang; Lee, Rena; Xing, Lei

    2015-03-01

    Conventional VMAT optimizes aperture shapes and weights at uniformly sampled stations, which is a generalization of the concept of a control point. Recently, rotational station parameter optimized radiation therapy (SPORT) has been proposed to improve the plan quality by inserting beams to the regions that demand additional intensity modulations, thus formulating non-uniform beam sampling. This work presents a new rotational SPORT planning strategy based on reweighted total-variation (TV) minimization (min.), using beam’s-eye-view dosimetrics (BEVD) guided beam selection. The convex programming based reweighted TV min. assures the simplified fluence-map, which facilitates single-aperture selection at each station for single-arc delivery. For the rotational arc treatment planning and non-uniform beam angle setting, the mathematical model needs to be modified by additional penalty term describing the fluence-map similarity and by determination of appropriate angular weighting factors. The proposed algorithm with additional penalty term is capable of achieving more efficient and deliverable plans adaptive to the conventional VMAT and SPORT planning schemes by reducing the dose delivery time about 5 to 10 s in three clinical cases (one prostate and two head-and-neck (HN) cases with a single and multiple targets). The BEVD guided beam selection provides effective and yet easy calculating methodology to select angles for denser, non-uniform angular sampling in SPORT planning. Our BEVD guided SPORT treatment schemes improve the dose sparing to femoral heads in the prostate and brainstem, parotid glands and oral cavity in the two HN cases, where the mean dose reduction of those organs ranges from 0.5 to 2.5 Gy. Also, it increases the conformation number assessing the dose conformity to the target from 0.84, 0.75 and 0.74 to 0.86, 0.79 and 0.80 in the prostate and two HN cases, while preserving the delivery efficiency, relative to conventional single-arc VMAT plans.

  6. An electromechanical based deformable model for soft tissue simulation.

    Science.gov (United States)

    Zhong, Yongmin; Shirinzadeh, Bijan; Smith, Julian; Gu, Chengfan

    2009-11-01

    Soft tissue deformation is of great importance to surgery simulation. Although a significant amount of research efforts have been dedicated to simulating the behaviours of soft tissues, modelling of soft tissue deformation is still a challenging problem. This paper presents a new deformable model for simulation of soft tissue deformation from the electromechanical viewpoint of soft tissues. Soft tissue deformation is formulated as a reaction-diffusion process coupled with a mechanical load. The mechanical load applied to a soft tissue to cause a deformation is incorporated into the reaction-diffusion system, and consequently distributed among mass points of the soft tissue. Reaction-diffusion of mechanical load and non-rigid mechanics of motion are combined to govern the simulation dynamics of soft tissue deformation. An improved reaction-diffusion model is developed to describe the distribution of the mechanical load in soft tissues. A three-layer artificial cellular neural network is constructed to solve the reaction-diffusion model for real-time simulation of soft tissue deformation. A gradient based method is established to derive internal forces from the distribution of the mechanical load. Integration with a haptic device has also been achieved to simulate soft tissue deformation with haptic feedback. The proposed methodology does not only predict the typical behaviours of living tissues, but it also accepts both local and large-range deformations. It also accommodates isotropic, anisotropic and inhomogeneous deformations by simple modification of diffusion coefficients.

  7. Electromechanical displacement of piezoelectric-electrostrictive monolithic bilayer composites

    Science.gov (United States)

    Ngernchuklin, P.; Akdoǧan, E. K.; Safari, A.; Jadidian, B.

    2009-02-01

    We examine the electromechanical displacement of piezoelectric-electrostrictive monolithic bilayer composites with various piezoelectric volume percentage obtained by cosintering piezoelectric 0.65Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 and electrostrictive 0.9Pb(Mg1/3Nb2/.3)O3-0.1PbTiO3 under unipolar and bipolar electric field excitation up to 10 kV/cm experimentally. It is shown that the effective d33 of the composites is limited by the electrostrictive layer, which acts as a capacitor in series to the piezoelectric layer, causing incomplete poling. We show that by controlling the volume content of the piezoelectric layer and constraining it with an electrostrictor, substantial strain amplification (15 μm for bipolar excitation) can be achieved while inducing asymmetry to the displacement with respect to the polarity of the applied field, which we discuss in the context of symmetry superposition.

  8. Electro-mechanical coupling of rotating 3D beams

    Directory of Open Access Journals (Sweden)

    Stoykov S.

    2016-01-01

    Full Text Available A rotating thin-walled beam with piezoelectric element is analysed. The beam is considered to vibrate in space, hence the longitudinal, transverse and torsional deformations are taken into account. The bending deformations of the beam are modelled by assuming Timoshenko's theory. Torsion is included by considering that the cross section rotates as a rigid body but can deform in longitudinal direction due to warping. The warping function is computed preliminary by the finite element method. The equation of motion is derived by the principle of virtual work and discretized in space by the Ritz method. Electro-mechanical coupling is included in the model by considering the internal electrical energy and the electric charge output. The piezo-electric constitutive relations are used in reduced form. The beam is assumed to rotate about a fixed axis with constant speed. The equation of motion is derived in rotating coordinate system, but the influence of the rotation of the coordinate system is taken into account through the inertia forces. Results in time domain are presented for different speeds of rotation and frequencies of vibration. The influence of the speed of rotation and of the frequency of vibration on the electrical output is presented and analysed.

  9. Electromechanical role of fixed charge in the mammalian tectorial membrane

    Science.gov (United States)

    Ghaffari, Roozbeh; Page, Scott; Farrahi, Shirin; Sellon, Jonathan B.; Freeman, Dennis M.

    2015-12-01

    The mammalian tectorial membrane (TM) is thought to play a purely mechanical role in stimulating cochlear sensory receptors, but the presence of glycosaminoglycans and associated fixed charge groups suggests that electromechanical properties also may be important. Here, we measure the fixed charge concentration of the TM (-7.1 mmol/L at physiological pH), and show that this concentration of fixed charge is sufficient to generate electrokinetic motions of the TM. Electrically-evoked TM motions were nanometer-scaled (5-200 nm), increased linearly with electric field amplitude (0.05-20 kV/m) and decreased with frequency (1-1000 Hz). This frequency dependence can be understood in terms of the interplay between electrophoresis and electro-osmosis. Although the electric fields applied in this study were large, they are comparable in amplitude to the electric fields generated near hair cell transduction channels. TM electrokinetics could thus play a role in the deflection of cochlear hair bundles in vivo.

  10. Computer-aided Teaching of Math in Electromechanics Vocational Course

    Directory of Open Access Journals (Sweden)

    Eduardo Shigueo Hoji

    2013-03-01

    Full Text Available This paper describes the experience of teaching mathematics in the electromechanics vocational course with aid of the computer. Instead of giving a bunch of equations and a calculator to the students, as it is usual in vocational courses, we offer them Octave, which is a numerical computational tool. Furthermore, the mathematical concepts involved in the solution of applied problems are provided within a multidisciplinary framework. The proposed approach helped to reduce the abstraction of mathematics for the students. Despite the deficiencies the students in vocational courses have in their formation, we could notice that their perception regarding mathematics has changed after figuring out that “a bunch of numbers” can be useful in the solution of problems they shall face in their professional life. The approach was applied to three groups already. All of them are composed of mature students, who passed by a flawed basic educational system and stayed away from school for a long time.

  11. Development of micro-electromechanical system (MEMS) cochlear biomodel

    Energy Technology Data Exchange (ETDEWEB)

    Ngelayang, Thailis Bounya Anak; Latif, Rhonira [Faculty of Electronic and Computer Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka (Malaysia)

    2015-05-15

    Human cochlear is undeniably one of the most amazing organs in human body. The functional mechanism is very unique in terms of its ability to convert the sound waves in the form of mechanical vibrations into the electrical nerve impulses. It is known that the normal human auditory system can perceive the audible frequency range between 20 Hz to 20 kHz. Scientists have conducted several researches trying to build the artificial basilar membrane in the human cochlea (cochlear biomodel). Micro-electromechanical system (MEMS) is one of the potential inventions that have the ability to mimic the active behavior of the basilar membrane. In this paper, an array of MEMS bridge beams that are mechanically sensitive to the perceived audible frequency has been proposed. An array of bridge bridge beams with 0.5 µm thickness and length varying from 200 µm to 2000 µm have been designed operate within the audible frequency range. In the bridge beams design, aluminium (Al), copper (Cu), tantalum (Ta) and platinum (Pt) have considered as the material for the bridge beam structure. From the finite element (FE) and lumped element (LE) models of the MEMS bridge beams, platinum has been found to be the best material for the cochlear biomodel design, closely mimicking the basilar membrane.

  12. Large scale electromechanical transistor with application in mass sensing

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Leisheng; Li, Lijie, E-mail: L.Li@swansea.ac.uk [Multidisciplinary Nanotechnology Centre, College of Engineering, Swansea University, Swansea SA2 8PP (United Kingdom)

    2014-12-07

    Nanomechanical transistor (NMT) has evolved from the single electron transistor, a device that operates by shuttling electrons with a self-excited central conductor. The unfavoured aspects of the NMT are the complexity of the fabrication process and its signal processing unit, which could potentially be overcome by designing much larger devices. This paper reports a new design of large scale electromechanical transistor (LSEMT), still taking advantage of the principle of shuttling electrons. However, because of the large size, nonlinear electrostatic forces induced by the transistor itself are not sufficient to drive the mechanical member into vibration—an external force has to be used. In this paper, a LSEMT device is modelled, and its new application in mass sensing is postulated using two coupled mechanical cantilevers, with one of them being embedded in the transistor. The sensor is capable of detecting added mass using the eigenstate shifts method by reading the change of electrical current from the transistor, which has much higher sensitivity than conventional eigenfrequency shift approach used in classical cantilever based mass sensors. Numerical simulations are conducted to investigate the performance of the mass sensor.

  13. A novel electromechanical approach to constant frequency power generation

    Science.gov (United States)

    Dishner, Bryan; Morris, Angela

    An alternate design approach to the hydrochemical constant speed drive (CSD) used on aircraft to drive synchronous generators at constant speed has been evaluated. The alternative design replaces hydraulic devices with advanced technology permanent magnet (PM) motor/generators which rely on power semiconductors in the speed compensation link to produce a constant speed output to the synchronous generator. The feasibility study for the product, electrically compensated CSD (ECCSD), has been demonstrated. The ECCSD program demonstrates the basic axial gear differential CSD concept of passing the power and speed trimming functions through gearing, while at the same time efficiently accomplishing the closed-loop speed control function electromechanically with small, high-speed motors. The ECCSD configuration chosen for development uses a 50,000 rev/min PM generator and a 50,000 rev/min motor. A thyristor-based AC-to-DC converter conditions the PM generator output. A transistor-based brushless DC-type motor drive is used with the PM motor. The hardware is described, and test results are presented.

  14. Grinding process monitoring based on electromechanical impedance measurements

    Science.gov (United States)

    Marchi, Marcelo; Guimarães Baptista, Fabricio; de Aguiar, Paulo Roberto; Bianchi, Eduardo Carlos

    2015-04-01

    Grinding is considered one of the last processes in precision parts manufacturing, which makes it indispensable to have a reliable monitoring system to evaluate workpiece surface integrity. This paper proposes the use of the electromechanical impedance (EMI) method to monitor the surface grinding operation in real time, particularly the surface integrity of the ground workpiece. The EMI method stands out for its simplicity and for using low-cost components such as PZT (lead zirconate titanate) piezoelectric transducers. In order to assess the feasibility of applying the EMI method to the grinding process, experimental tests were performed on a surface grinder using a CBN grinding wheel and a SAE 1020 steel workpiece, with PZT transducers mounted on the workpiece and its holder. During the grinding process, the electrical impedance of the transducers was measured and damage indices conventionally used in the EMI method were calculated and compared with workpiece wear, indicating the surface condition of the workpiece. The experimental results indicate that the EMI method can be an efficient and cost-effective alternative for monitoring precision workpieces during the surface grinding process.

  15. Electromechanical Properties of Small Transition-Metal Dichalcogenide Nanotubes

    Directory of Open Access Journals (Sweden)

    Nourdine Zibouche

    2014-04-01

    Full Text Available Transition-metal dichalcogenide nanotubes (TMC-NTs are investigated for their electromechanical properties under applied tensile strain using density functional-based methods. For small elongations, linear strain-stress relations according to Hooke’s law have been obtained, while for larger strains, plastic behavior is observed. Similar to their 2D counterparts, TMC-NTs show nearly a linear change of band gaps with applied strain. This change is, however, nearly diameter-independent in case of armchair forms. The semiconductor-metal transition occurs for much larger deformations compared to the layered tube equivalents. This transition is faster for heavier chalcogen elements, due to their smaller intrinsic band gaps. Unlike in the 2D forms, the top of valence and the bottom of conduction bands stay unchanged with strain, and the zigzag NTs are direct band gap materials until the semiconductor-metal transition. Meanwhile, the applied strain causes modification in band curvature, affecting the effective masses of electrons and holes. The quantum conductance of TMC-NTs starts to occur close to the Fermi level when tensile strain is applied.

  16. Electromechanical, acoustical and thermodynamical characterization of a low-frequency sonotrode-type transducer in a small sonoreactor at different excitation levels and loading conditions.

    Science.gov (United States)

    Petošić, Antonio; Horvat, Marko; Režek Jambrak, Anet

    2017-11-01

    The paper reports and compares the results of the electromechanical, acoustical and thermodynamical characterization of a low-frequency sonotrode-type ultrasonic device inside a small sonoreactor, immersed in three different loading media, namely, water, juice and milk, excited at different excitation levels, both below and above the cavitation threshold. The electroacoustic efficiency factor determined at system resonance through electromechanical characterization in degassed water as the reference medium is 88.7% for the device in question. This efficiency can be reduced up to three times due to the existence of a complex sound field in the reactor in linear driving conditions below the cavitation threshold. The behaviour of the system is more stable at higher excitation levels than in linear operating conditions. During acoustical characterization, acoustic pressure is spatially averaged, both below and above the cavitation threshold. The standing wave patterns inside the sonoreactor have a stronger influence on the variation of the spatially distributed RMS pressure in linear operating conditions. For these conditions, the variation of ±1.7dB was obtained, compared to ±1.4dB obtained in highly nonlinear regime. The acoustic power in the sonoreactor was estimated from the magnitude of the averaged RMS pressure, and from the reverberation time of the sonoreactor as the representation of the losses. The electroacoustic efficiency factors obtained through acoustical and electromechanical characterization are in a very good agreement at low excitation levels. The irradiated acoustic power estimated in nonlinear conditions differs from the dissipated acoustic power determined with the calorimetric method by several orders of magnitude. The number of negative pressure peaks that represent transient cavitation decreases over time during longer treatments of a medium with high-power ultrasound. The number of negative peaks decreases faster when the medium and the

  17. [Toward exploration of morphological diversity of measurable traits of mammalian skull. 2. Scalar and vector parameters of the forms of group variation].

    Science.gov (United States)

    Lisovskiĭ, A A; Pavlinov, I Ia

    2008-01-01

    Any morphospace is partitioned by the forms of group variation, its structure is described by a set of scalar (range, overlap) and vector (direction) characteristics. They are analyzed quantitatively for the sex and age variations in the sample of 200 skulls of the pine marten described by 14 measurable traits. Standard dispersion and variance components analyses are employed, accompanied with several resampling methods (randomization and bootstrep); effects of changes in the analysis design on results of the above methods are also considered. Maximum likelihood algorithm of variance components analysis is shown to give an adequate estimates of portions of particular forms of group variation within the overall disparity. It is quite stable in respect to changes of the analysis design and therefore could be used in the explorations of the real data with variously unbalanced designs. A new algorithm of estimation of co-directionality of particular forms of group variation within the overall disparity is elaborated, which includes angle measures between eigenvectors of covariation matrices of effects of group variations calculated by dispersion analysis. A null hypothesis of random portion of a given group variation could be tested by means of randomization of the respective grouping variable. A null hypothesis of equality of both portions and directionalities of different forms of group variation could be tested by means of the bootstrep procedure.

  18. Electromechanical Battery Program at the Lawrence Livermore National Laboratory

    Science.gov (United States)

    Post, R. F.; Bender, D. A.; Merritt, B. T.

    1994-05-01

    New materials and new design concepts are being incorporated in a new approach to an old idea - flywheel energy storage - to create an important alternative to the electrochemical storage battery for use in electric vehicles or for stationary applications, such as computer back-up power or utility load-leveling. We visualize such EMB's (electromechanical batteries) as being modular in character, with small (1-5 kWh) modules being used for power-conditioning and for vehicular use, and paralleled 25 kWh modules being used for bulk storage, i.e., load-leveling, applications. In a funded program at the Laboratory two fractional kWh, 200 kW (design peak power) modules have been constructed and subjected to shake-down testing. Their design for high peak power was prompted by awareness of a particular commercial need, as a component in a power-line conditioning device. In addition to such stationary applications, the high power capability of our EMB designs makes them attractive for use in hybrid-electric vehicles. Important elements of the LLNL program include the development of passive magnetic bearings and the application of new high-efficiency permanent magnet arrays to an ironless generator/motor. Use of these particular elements, together with a multi-ring design for the flywheel rotor, is particularly conducive to a systemic approach to the design of an EMB module. These particular design developments have been motivated by the economic issues of simplification, lowered cost, and extended maintenance-free service life.

  19. Design and application of electromechanical actuators for deep space missions

    Science.gov (United States)

    Haskew, Tim A.; Wander, John

    1994-02-01

    This progress report documents research and development efforts performed from August 16, 1993 through February 15, 1994 on NASA Grant NAG8-240, 'Design and Application of Electromechanical Actuators for Deep Space Missions.' Following the executive summary are four report sections: Motor Selection, Tests Stand Development, Health Monitoring and Fault Management, and Experiment Planning. Three specific motor types have been considered as prime movers for TVC EMA applications: the brushless dc motor, the permanent magnet synchronous motor, and the induction motor. The fundamental finding was that, in general, the primary performance issues were energy efficiency and thermal dissipation (rotor heating). In terms of all other issues, the three motor types were found to compare quite equally. Among the design changes made to the test stand since the last progress report is the addition of more mounting holes in the side beams. These additional holes allow the movable end beam to be attached in a greater number of positions than previously. With this change the movable end beam can move from full forward to full back in three inch increments. Specific mathematical details on the approach that have been employed for health monitoring and fault management (HMFM) have been reported previously. This approach is based on and adaptive Kalman filter strategy. In general, a bank of filters can be implemented for each primary fault type. Presently under consideration for the brushless dc machine are the following faults: armature winding open-circuits, armature winding short-circuits (phase-to-phase and phase-to-ground), bearing degradation, and rotor flux weakening. The mechanically oriented experiments include transient loading experiments, transverse loading experiment, friction experiment, motor performance experiment, and HMFM experiment.

  20. Nano-electromechanical oscillators (NEMOs) for RF technologies.

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, Joel Robert; Czaplewski, David A.; Gibson, John Murray (Argonne National Laboratory, Argonne, IL); Webster, James R.; Carton, Andrew James; Keeler, Bianca Elizabeth Nelson; Carr, Dustin Wade; Friedmann, Thomas Aquinas; Tallant, David Robert; Boyce, Brad Lee; Sullivan, John Patrick; Dyck, Christopher William; Chen, Xidong (Cedarville University, Cedarville, OH)

    2004-12-01

    Nano-electromechanical oscillators (NEMOs), capacitively-coupled radio frequency (RF) MEMS switches incorporating dissipative dielectrics, new processing technologies for tetrahedral amorphous carbon (ta-C) films, and scientific understanding of dissipation mechanisms in small mechanical structures were developed in this project. NEMOs are defined as mechanical oscillators with critical dimensions of 50 nm or less and resonance frequencies approaching 1 GHz. Target applications for these devices include simple, inexpensive clocks in electrical circuits, passive RF electrical filters, or platforms for sensor arrays. Ta-C NEMO arrays were used to demonstrate a novel optomechanical structure that shows remarkable sensitivity to small displacements (better than 160 fm/Hz {sup 1/2}) and suitability as an extremely sensitive accelerometer. The RF MEMS capacitively-coupled switches used ta-C as a dissipative dielectric. The devices showed a unipolar switching response to a unipolar stimulus, indicating the absence of significant dielectric charging, which has historically been the major reliability issue with these switches. This technology is promising for the development of reliable, low-power RF switches. An excimer laser annealing process was developed that permits full in-plane stress relaxation in ta-C films in air under ambient conditions, permitting the application of stress-reduced ta-C films in areas where low thermal budget is required, e.g. MEMS integration with pre-existing CMOS electronics. Studies of mechanical dissipation in micro- and nano-scale ta-C mechanical oscillators at room temperature revealed that mechanical losses are limited by dissipation associated with mechanical relaxation in a broad spectrum of defects with activation energies for mechanical relaxation ranging from 0.35 eV to over 0.55 eV. This work has established a foundation for the creation of devices based on nanomechanical structures, and outstanding critical research areas that need

  1. An electromechanical coupling model of a bending vibration type piezoelectric ultrasonic transducer.

    Science.gov (United States)

    Zhang, Qiang; Shi, Shengjun; Chen, Weishan

    2016-03-01

    An electromechanical coupling model of a bending vibration type piezoelectric ultrasonic transducer is proposed. The transducer is a Langevin type transducer which is composed of an exponential horn, four groups of PZT ceramics and a back beam. The exponential horn can focus the vibration energy, and can enlarge vibration amplitude and velocity efficiently. A bending vibration model of the transducer is first constructed, and subsequently an electromechanical coupling model is constructed based on the vibration model. In order to obtain the most suitable excitation position of the PZT ceramics, the effective electromechanical coupling coefficient is optimized by means of the quadratic interpolation method. When the effective electromechanical coupling coefficient reaches the peak value of 42.59%, the optimal excitation position (L1=22.52 mm) is found. The FEM method and the experimental method are used to validate the developed analytical model. Two groups of the FEM model (the Group A center bolt is not considered, and but the Group B center bolt is considered) are constructed and separately compared with the analytical model and the experimental model. Four prototype transducers around the peak value are fabricated and tested to validate the analytical model. A scanning laser Doppler vibrometer is employed to test the bending vibration shape and resonance frequency. Finally, the electromechanical coupling coefficient is tested indirectly through an impedance analyzer. Comparisons of the analytical results, FEM results and experiment results are presented, and the results show good agreement. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Electromechanical decoupled model for cantilever-beam piezoelectric energy harvesters with inductive-resistive circuits and its application in galloping mode

    Science.gov (United States)

    Tan, Ting; Yan, Zhimiao

    2017-03-01

    The electromechanical decoupled distributed parameter model for cantilever-beam piezoelectric energy harvesters with inductive-resistive circuits is proposed. The modified natural frequency and electrical damping for series and parallel inductive-resistive cases are derived, which are functions of the first natural frequency of the cantilever beam, capacitance of the piezoelectric layers, load resistance, inductance and electromechanical coupling term. As a demonstration, we apply the decoupled model to cantilever-beam piezoelectric energy harvesters operated in the galloping mode. The average harvested power is derived as an algebraic expression of the electrical damping in addition to the wind speed, aerodynamic parameters of the bluff body and mechanical properties of the cantilever beam. Besides these impacts, the amplitude of the tip displacement also depends on its modified natural frequency. The electromechanical decoupled model and its analytical solutions are confirmed by the numerical solutions of the coupled model for the galloping mode. The theoretical expressions for the maximal harvested power and corresponding tip displacement at the optimal electrical damping are then developed. The cantilever-beam piezoelectric energy harvester with the inductive-resistive circuit has multiple solution sets of the modified natural frequency and electrical damping. Any optimal electrical damping can be realized by series or parallel inductive-resistive circuit, which cannot be accomplished by pure resistive circuit. By introducing the inductance to the circuit of the galloping piezoelectric energy harvester, the performance of such a system is improved with larger maximal harvested power at high wind speed and smaller amplitude of the tip displacement. This study provides a theoretical approach to capture the intrinsic effects of the inductance in addition to the load resistance on the performance of cantilever-beam piezoelectric energy harvesters.

  3. The Sensitivity Analysis of Parameters of Urban Runoff Models due to Variations of Basin Characteristics(I) : Development of Sensitivity Analysis Method

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Kyu Woo [Dongeui University, Pusan (Korea); Cho, Won Cheol [Yonsei University, Seoul (Korea)

    1998-06-30

    In this study, the new dimensionless values were defined and proposed to determine the parameters of urban runoff models based on the relative sensitivity analysis. Also, the sensitivity characteristics of each parameter were investigated. In order to analyze the parameter sensitivities of each model, total runoff ratio, peak runoff ratio, runoff sensitivity ratio, sensitivity ratio of total runoff, and sensitivity ratio of peak runoff were defined. Total runoff ratio(Q{sub TR}) = Total runoff of corresponding step / Maximum total runoff. Peak runoff ratio(Q{sub PR}) = Peak runoff corresponding step / Maximum peak runoff. Runoff sensitivity ratio(Q{sub SR}) = Q{sub TR} / Q{sub PR}. And for estimation of sensitivity ratios based on the scale of basin area, rainfall distributions and rainfall durations in ILLUDAS and SWMM, the reasonable ranges of parameters were proposed. (author). 21 refs., 2 tabs., 2 figs.

  4. Bending-induced electromechanical coupling and large piezoelectric response in a micromachined diaphragm

    KAUST Repository

    Wang, Zhihong

    2013-11-04

    We investigated the dependence of electromechanical coupling and the piezoelectric response of a micromachined Pb(Zr 0.52 Ti 0.48)O 3 (PZT) diaphragm on its curvature by observing the impedance spectrum and central deflection responses to a small AC voltage. The curvature of the diaphragm was controlled by applying air pressure to its back. We found that a depolarized flat diaphragm does not initially exhibit electromechanical coupling or the piezoelectric response. However, upon the application of static air pressure to the diaphragm, both electromechanical coupling and the piezoelectric response can be induced in the originally depolarized diaphragm. The piezoelectric response increases as the curvature increases and a giant piezoelectric response can be obtained from a bent diaphragm. The obtained results clearly demonstrate that a high strain gradient in a diaphragm can polarize a PZT film through a flexoelectric effect, and that the induced piezoelectric response of the diaphragm can be controlled by adjusting its curvature.

  5. High-performance electromechanical transduction using laterally-constrained dielectric elastomers part I: Actuation processes

    Science.gov (United States)

    Koh, Soo Jin Adrian; Keplinger, Christoph; Kaltseis, Rainer; Foo, Choon-Chiang; Baumgartner, Richard; Bauer, Siegfried; Suo, Zhigang

    2017-08-01

    A dielectric elastomer transducer is a deformable capacitor, and is under development as a sensor, actuator, or generator. Among various geometric configurations, laterally-constrained transducer, also known as pure-shear transducer, is easy to implement and effective to couple mechanical force and electrical voltage. This analytical study reveals that lateral pre-stretch enhances actuation, far exceeding previously reported actuation strokes. Laterally-constrained transducers exhibit complex electromechanical behavior. As voltage increases, an actuator may undergo electromechanical instability, or form wrinkles, or suffer electrical breakdown. We survey the behavior of actuators under all possible states of pre-stretches, and identify five modes of actuation. Our analysis predicts that laterally-constrained actuators can achieve actuation stroke of 1000% for an acrylic elastomer, and 230% for natural rubber. This analysis opens the door to design actuators of simple geometry capable of a very large range of electromechanical actuation.

  6. Effect of rare-earth additives on electromechanical properties of modified lead titanate ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Suwannasiri, Thitima; Safari, A. (Rutgers, The State Univ. of New Jersey, Piscataway, NJ (United States). Dept. of Ceramic Science and Engineering)

    1993-12-01

    The influence of rare-earth additives, such as La, Nd, Sm, and Gd, and poling conditions on the electromechanical properties of (Pb[sub 1[minus]3x/2]Ln[sub x])(Ti[sub 0.98]Mn[sub 0.02])O[sub 3] compositions, x = 0.04--0.12, were investigated. The type and amount of additive were found to affect the lattice anisotropy, dielectric constant, and electromechanical properties. A large electro-mechanical anisotropy (k[sub t]lk[sub p]) could be obtained in 10 mol% Sm-modified and 8 mol% Gd-modified lead titanate ceramics, and seemed to correlate to a low Poisson's ratio.

  7. Theoretical study of the electromechanical efficiency of a loaded tubular dielectric elastomer actuator

    DEFF Research Database (Denmark)

    Rechenbach, Björn; Willatzen, Morten; Lassen, Benny

    2016-01-01

    The electromechanical efficiency of a loaded tubular dielectric elastomer actuator (DEA) is investigated theoretically. In previous studies, the external system, on which the DEA performs mechanical work, is implemented implicitly by prescribing the stroke of the DEA in a closed operation cycle....... Here, a more generic approach, modelling the external system by a frequency-dependent mechanical impedance which exerts a certain force on the DEA depending on its deformation, is chosen. It admits studying the dependence of the electromechanical efficiency of the DEA on the external system. A closed...... operation cycle is realized by exciting the DEA electrically by a sinusoidal voltage around a bias voltage. A detailed parametric study shows that the electromechanical efficiency is highly dependent on the frequency, amplitude, and bias of the excitation voltage and the mechanical impedance of the external...

  8. Nonlinear electromechanical modelling and dynamical behavior analysis of a satellite reaction wheel

    Science.gov (United States)

    Aghalari, Alireza; Shahravi, Morteza

    2017-12-01

    The present research addresses the satellite reaction wheel (RW) nonlinear electromechanical coupling dynamics including dynamic eccentricity of brushless dc (BLDC) motor and gyroscopic effects, as well as dry friction of shaft-bearing joints (relative small slip) and bearing friction. In contrast to other studies, the rotational velocity of the flywheel is considered to be controllable, so it is possible to study the reaction wheel dynamical behavior in acceleration stages. The RW is modeled as a three-phases BLDC motor as well as flywheel with unbalances on a rigid shaft and flexible bearings. Improved Lagrangian dynamics for electromechanical systems is used to obtain the mathematical model of the system. The developed model can properly describe electromechanical nonlinear coupled dynamical behavior of the satellite RW. Numerical simulations show the effectiveness of the presented approach.

  9. Electromechanical transducers at the nanoscale: actuation and sensing of motion in nanoelectromechanical systems (NEMS).

    Science.gov (United States)

    Ekinci, K L

    2005-08-01

    Electromechanical devices are rapidly being miniaturized, following the trend in commercial transistor electronics. Miniature electromechanical devices--now with dimensions in the deep sub-micrometer range--are envisioned for a variety of applications as well as for accessing interesting regimes in fundamental physics. Among the most important technological challenges in the operation of these nanoelectromechanical systems (NEMS) are the actuation and detection of their sub-nanometer displacements at high frequencies. In this Review, we shall focus on this most central concern in NEMS technology: realization of electromechanical transducers at the nanoscale. The currently available techniques to actuate and detect NEMS motion are introduced, and the accuracy, bandwidth, and robustness of these techniques are discussed.

  10. Electromechanical phase transition of a dielectric elastomer tube under internal pressure of constant mass

    Directory of Open Access Journals (Sweden)

    Song Che

    2017-05-01

    Full Text Available The electromechanical phase transition for a dielectric elastomer (DE tube has been demonstrated in recent experiments, where it is found that the unbulged phase gradually changed into bulged phase. Previous theoretical works only studied the transition process under pressure control condition, which is not consistent with the real experimental condition. This paper focuses on more complex features of the electromechanical phase transition under internal pressure of constant mass. We derive the equilibrium equations and the condition for coexistent states for a DE tube under an internal pressure, a voltage through the thickness and an axial force. We find that under mass control condition the voltage needed to maintain the phase transition increases as the process proceeds. We analyze the entire process of electromechanical phase transition and find that the evolution of configurations is also different from that for pressure control condition.

  11. Dynamic Modeling and Control of Electromechanical Coupling for Mechanical Elastic Energy Storage System

    Directory of Open Access Journals (Sweden)

    Yang Yu

    2013-01-01

    Full Text Available The structural scheme of mechanical elastic energy storage (MEES system served by permanent magnet synchronous motor (PMSM and bidirectional converters is designed. The aim of the research is to model and control the complex electromechanical system. The mechanical device of the complex system is considered as a node in generalized coordinate system, the terse nonlinear dynamic model of electromechanical coupling for the electromechanical system is constructed through Lagrange-Maxwell energy method, and the detailed deduction of the mathematical model is presented in the paper. The theory of direct feedback linearization (DFL is applied to decouple the nonlinear dynamic model and convert the developed model from nonlinear to linear. The optimal control theory is utilized to accomplish speed tracking control for the linearized system. The simulation results in three different cases show that the proposed nonlinear dynamic model of MEES system is correct; the designed algorithm has a better control performance in contrast with the conventional PI control.

  12. Electromechanical abdominal massage and colonic function in individuals with a spinal cord injury and chronic bowel problems.

    NARCIS (Netherlands)

    Janssen, T.W.J.; Prakken, E.S.; Hendriks, J.M.; Lourens, C; van der Vlist, J.; Smit, C.A.

    2014-01-01

    Study Design:A prospective intervention of noninvasive abdominal massage using an electromechanical apparatus on bowel function in individuals with spinal cord injury (SCI).Objectives:To evaluate the effects of noninvasive abdominal massage using an electromechanical apparatus on bowel function in

  13. Design, construction, and evaluation of "sensor lock": an electromechanical stance control knee joint.

    Science.gov (United States)

    Arazpour, Mokhtar; Ahmadi Bani, Monireh; Baniasad, Mina; Samadian, Mohammad; Golchin, Navid

    2017-03-28

    Most currently-available stance control knee ankle foot orthoses (SCKAFOs) still need full knee extension to lock the knee joint, and they are still noisy, bulky, and heavy. Therefore, the aim of this study was to design, construct, and evaluate an original electromechanical SCKAFO knee joint that could feasibly solve these problems, and thus address the problems of current stance control knee joints with regards to their structure, function, cosmesis, and cost. Ten able-bodied (AB) participants and two (knee ankle foot orthosis) KAFO users were recruited to participate in the study. A custom SCKAFO with the same set of components was constructed for each participant. Lower limb kinematics were captured using a 6-camera, video-based motion analysis system. For AB participants, significant differences were found between normal walking and walking with the SCKAFO for temporal-spatial parameters and between orthoses with two modes of knee joints in the healthy subjects. Walking with stance control mode produced greater walking speed and step length, greater knee flexion during swing, and less pelvic obliquity than walking with a locked knee, for both AB and KAFO users. The feasibility of this new knee joint with AB people was demonstrated. Implications for rehabilitation Stance control knee ankle foot orthoses (SCKAFOs) are designed to stop knee flexion in stance phase and provide free knee movement during swing phase of walking. Due to their high cost, size, excessive weight, and poor performance, few SCKAFO were optimal clinically and commercially. The feasibility of the new knee joint with able-bodied people and poliomyelitis subjects was demonstrated.

  14. Energy Method for Identification of Electromechanical Devices and Systems

    OpenAIRE

    D. I. Rodkin; Y. V. Romashihin

    2011-01-01

    The paper considers a method for determination of induction motor electromagnetic parameters while using complete instant power equations. The methods for AC motor electromagnetic parameters are proposed in the paper. The paper reveals the method efficiency while determining induction motor electromagnetic parameters

  15. Energy Method for Identification of Electromechanical Devices and Systems

    Directory of Open Access Journals (Sweden)

    D. I. Rodkin

    2011-01-01

    Full Text Available The paper considers a method for determination of induction motor electromagnetic parameters while using complete instant power equations. The methods for AC motor electromagnetic parameters are proposed in the paper. The paper reveals the method efficiency while determining induction motor electromagnetic parameters

  16. The principles of electronic and electromechanic power conversion a systems approach

    CERN Document Server

    Ferreira, Braham

    2013-01-01

    Teaching the principles of power electronics and electromechanical power conversion through a unique top down systems approach, The Principles of Electromechanical Power Conversion takes the role and system context of power conversion functions as the starting point. Following this approach, the text defines the building blocks of the system and describes the theory of how they exchange power with each other. The authors introduce a modern, simple approach to machines, which makes the principles of field oriented control and space vector theory approachable to undergraduate students as well as

  17. Modeling and Investigation of Electromechanical Valve Train Actuator at simulated Pressure conditions

    DEFF Research Database (Denmark)

    Habib, Tufail

    2012-01-01

    In an electromechanical valve actuated engine, the valves are driven by solenoid-type actuators and cam-shaft is eliminated. Control of each valve provides flexibility in valve timings over all engine conditions and achieves the benefits of variable valve timing(VVT). This paper is about investig......In an electromechanical valve actuated engine, the valves are driven by solenoid-type actuators and cam-shaft is eliminated. Control of each valve provides flexibility in valve timings over all engine conditions and achieves the benefits of variable valve timing(VVT). This paper is about...

  18. The Possible Role of Dentin as a Piezoelectric Signal Generator by Determining the Elec-tromechanical Coupling Factor of Dentin

    Directory of Open Access Journals (Sweden)

    Atabak Shahidi

    2011-08-01

    Full Text Available Introduction: This article aimed at calculation of the electromechanical coupling factor of dentin which is an indicator of the effectiveness with which a piezoelectric material converts electrical en-ergy into mechanical energy, or vice versa. The hypothesis: The electro-mechanical coupling factor of dentin was determined in mode 11 and 33 by calculating the ratio of the produced electrical energy to the stored elastic energy in dentin under applied pressure. This study showed that the electromechanical coupling factor of dentin was affected by the direction of the applied force and the moisture content of dentin. Also dentin was a weak electromechanical energy converter which might be categorized as a piezoelectric pressure sensor.Evaluation of the hypothesis: Determination of the electrome-chanical coupling factor of dentin and its other piezoelectric constants is essential to investigate the biologic role of piezoelectricity in tooth.

  19. Assessment of Atrial Electromechanical Delay and Left Atrial Mechanical Functions in Patients with Ulcerative Colitis.

    Science.gov (United States)

    Nar, Gokay; Ergul, Bilal; Aksan, Gokhan; Inci, Sinan

    2016-07-01

    Ulcerative colitis (UC) is a common inflammatory bowel disease causing systemic inflammation, which may also affect the cardiovascular system, as well as other organ systems. The aim of the current study was to evaluate left atrial (LA) mechanical functions and duration of atrial electromechanical delay (AEMD) with echocardiography in patients with UC. A total of 91 patients, 45 with UC (Group 1) and 46 healthy individuals as control (Group 2) were included in the study. The demographic and laboratory data were recorded, and echocardiographic measurements were taken for all patients. In the evaluation of basal clinical and laboratory findings, no difference was detected between the two groups, except for white blood cell count (WBC) (8.26 ± 2.71 vs. 7.06 ± 1.70, P = 0.013) and high-sensitivity C-reactive protein (Hs-CRP; 3.4 ± 1.7 vs. 1.0 ± 0.8, P < 0.001). The echocardiographic assessment revealed that the diastolic parameters such as E-, E/A-, and E- waves decreased in the UC group when compared to the control group. LA mechanical functions were different between groups, except for left atrial (LA) maximal volume: LA minimum volume (22.2 ± 12.9 vs. 15.3 ± 4.7, P = 0.001), LA volume before atrial systole (29.9 ± 14.2 vs. 24.2 ± 4.9, P = 0.021), LA ejection fraction (27.4 ± 16.5 vs. 38.6 ± 10.1, P < 0.001), LA total emptying volume (17.9 ± 6.9 vs. 21.9 ± 5.9, P = 0.004), LA active emptying fraction (27.4 ± 16.5 vs. 38.6 ± 10.1, P < 0.001), LA active emptying volume (7.7 ± 3.6 vs. 9.4 ± 2.9, P = 0.013), LA passive emptying fraction (26.8 ± 10.2 vs. 33.2 ± 9.2, P = 0.002), and LA passive emptying volume (10.3 ± 4.9 vs. 12.5 ± 4.5, P = 0.029). There was a significant difference between the groups in terms of AEMD durations, except time interval from the onset of the P-wave on the surface ECG to the peak of the late diastolic wave (PA) of the tricuspid valve. The correlation analysis revealed that age and duration of disease were correlated with

  20. Gallium nitride nanowires: Synthesis, resonant electromechanical properties, ion beam disorder effect on contact conduction, and heterojunction fabrication

    Science.gov (United States)

    Nam, Chang-Yong

    In this study, we develop a systematic route toward gallium nitride (GaN) nanowire (NW) synthesis and device development covering; GaN NW growth, morphology control, resonant electromechanical property measurement, focused ion beam (FIB) direct electrical contact patterning, conduction mechanism analysis at the FIB contacts, and Si-GaN NW p-n heterojunction fabrication. A variation of GaN NW's morphology and crystallographic growth orientation occurs upon the change of nitrogen source (NH3) feeding rate during vapor-solid (VS) type thermal chemical vapor deposition (CVD). A simplistic advection model estimates reaction condition, and the variation in Ga reactant diffusion length on GaN's polar surfaces explains the phenomena. The use of Au/Pd catalyst leads to vapor-liquid-solid (VLS) type growth with a higher yield. We briefly discuss the VLS growth mechanism distinct from the ordinary binary cases such as Si NW growth using Au catalyst. A self-branching growth is observed, and its mechanism is also addressed. Micro-Raman spectroscopy suggests growth temperature can influence crystallinity and doping concentration in the NWs. We perform an in situ electromechanical resonance study by transmission electron microscopy (TEM). The Young's modulus E of GaN NW decreases below the bulk value as diameter d decreases. The presence of stacking faults along the NWs' axis might be related. NWs' significantly high resonance quality factor Q suggests potential applications for nanoelectromechanical system (NEMS). We observe polarized resonant vibrations and attribute them to the asymmetric cross-sections of NWs. We direct-write electrical contacts to GaN NWs using FIB-Pt deposition. I-V evolves from low-resistant rectifying to ohmic as d decreases despite the fact that Pt is a typical Schottky metal to n-GaN. I-V-T is strongly non-metallic, and a back-to-back Schottky junction model and Mott variable range hopping (VRH) well describe contact conductions for the large and small

  1. Temporal Variation in Water Quality Parameters under Different Vegetative Communities in Two Flooded Forests of the Northern Pantanal, Mato Grosso, Brazil

    Science.gov (United States)

    Couto, E. G.; Dalmagro, H. J.; Lathuilliere, M. J.; Pinto Junior, O. B.; Johnson, M. S.

    2013-12-01

    The Pantanal is one of the largest flood plains in the world, and is characterized by large variability in vegetative communities and flooding dynamics. Some woody plant species have been observed to colonize large areas forming monospecific stands. We measured chemical parameters of flood waters including dissolved organic carbon (DOC), nitrate (NO3), dissolved oxygen (DO), and carbon dioxide (CO2) as well as physical parameters such as photosynthetically active radiation (PAR), temperature (Tw), turbidity (Turb) and water levels (WL). These chemical and physical measurements were conducted with the intent to characterize spatial and temporal differences of monospecific stands in order to understand if these different formations alter the biogeochemistry of the Pantanal waters. Water sample campaigns were conducted during the inundation period of January to May 2013 in two areas located in the Private Reserve of the Brazilian Social Service of Commerce (RPPN-SESC) near Poconé, Mato Grosso. Research sites included: (1) a flooded tall-stature forest (known as Cambarazal) dominated by the Vochysia divergens species; and (2) in a flooded scrub forest (known as Baia das Pedras) dominated by the Combretum lanceolatum species. Results showed three principal factors which explained 80% of variance in aquatic physical and chemical parameters. The first factor (PCA-1) explained 38% of variance (DO, PAR and WL), PCA-2 explained 23% (NO3, Tw, DOC), while PCA-3 explained only 19% of variance (CO2 and Turb). During the entire study period, the major concentration of variables were observed in the flooded forest. Physical variables presented small alterations, with the exception of water levels, that were greater in the flooded forest. With respect to temporal variables, all chemical parameters were greater at the beginning of the inundation and gradually dropped with the water level. With this work, we observed that the different monospecific formations influenced water

  2. Electromechanical properties of an ultrathin layer of directionally aligned helical polypeptides

    NARCIS (Netherlands)

    Jaworek, T.; Neher, D.; Wegner, G.; Wieringa, R.H.; Schouten, A.J.

    1998-01-01

    The electromechanical properties of a monomolecular film of poly-gamma-benzyl-L-glutamate (PBLG) 15 nanometers thick grafted at the carboxyl-terminal end to a flat aluminum surface were measured. The field-induced change in film thickness, dominated by a large inverse-piezoelectric effect,

  3. Repeated exercise stress impairs volitional but not magnetically evoked electromechanical delay of the knee flexors.

    Science.gov (United States)

    Minshull, Claire; Eston, Roger; Bailey, Andrea; Rees, Dai; Gleeson, Nigel

    2012-01-01

    The effects of serial episodes of fatigue and recovery on volitional and magnetically evoked neuromuscular performance of the knee flexors were assessed in 20 female soccer players during: (i) an intervention comprising 4 × 35 s maximal static exercise, and (ii) a control condition. Volitional peak force was impaired progressively (-16% vs. baseline: 235.3 ± 54.7 to 198.1 ± 38.5 N) by the fatiguing exercise and recovered to within -97% of baseline values following 6 min of rest. Evoked peak twitch force was diminished subsequent to the fourth episode of exercise (23.3%: 21.4 ± 13.8 vs. 16.4 ± 14.6 N) and remained impaired at this level throughout the recovery. Impairment of volitional electromechanical delay performance following the first episode of exercise (25.5%: 55.3 ± 11.9 vs. 69.5 ± 24.5 ms) contrasted with concurrent improvement (10.0%: 24.5 ± 4.7 vs. 22.1 ± 5.0 ms) in evoked electromechanical delay (P exercise provoked substantial impairments to volitional strength and volitional electromechanical delay that showed differential patterns of recovery. However, improved evoked electromechanical delay performance might identify a dormant capability for optimal muscle responses during acute stressful exercise and an improved capacity to maintain dynamic joint stability during critical episodes of loading.

  4. Immediate effects of different treatments for the wrist joints of subdominant hands, using electromechanical reaction time.

    Science.gov (United States)

    Hu, Chunying; Huang, Qiuchen; Yu, Lili; Zhou, Yue; Gu, Rui; Cui, Yao; Ge, Meng; Xu, Yanfeng; Liu, Jianfeng

    2016-08-01

    [Purpose] The aim of this study was to examine the immediate effects of muscle strength training and neuromuscular joint facilitation distal resistance training on wrist joints by using electromechanical reaction time. [Subjects and Methods] The subjects were 12 healthy young people (24.2 ± 3.1 years, 169.7 ± 6.5 cm, 65.3 ± 12.6 kg). Two kinds of isotonic contraction techniques were applied on the wrist joint: the wrist joint extension muscle strength training and the wrist joint extension pattern of neuromuscular joint facilitation. The electromechanical reaction time, premotor time, and motor time of the left upper limb were measured before and after each intervention session of muscle strength training and neuromuscular joint facilitation. [Results] The neuromuscular joint facilitation group showed significant shortening of the electromechanical reaction time and motor time after the intervention. [Conclusion] These results suggest that the electromechanical reaction time and motor time of the wrist joint can be improved by neuromuscular joint facilitation together with proximal resistance training, which can be used as a new form of exercise for improving the functions of subdominant hand wrist joints.

  5. Corrosion Resistance of Steel 45 Subjected to Electromechanical Treatment and Surface Plastic Deformation

    Science.gov (United States)

    Dudkina, N. G.

    2018-01-01

    The corrosion properties of normalized steel 45 are studied after a combined hardening of its surface layer, which consists of electromechanical treatment and surface plastic deformation (EMT + SPD). The effect of different aggressive environments on the structure, microhardness and corrosion rate of the hardened surface layer is determined.

  6. The electromechanical substrate for response to cardiac resynchronization therapy in patients with right bundle branch block

    DEFF Research Database (Denmark)

    Atwater, Brett D; Wagner, Galen S; Kisslo, Joseph

    2017-01-01

    BACKGROUND: Some patients with RBBB may respond to cardiac resynchronization therapy (CRT). However, little is known regarding the electromechanical substrate for CRT and whether this is the optimal pacing strategy. METHODS: This was a pilot prospective double crossover randomized controlled clin...

  7. Effects on the electro-mechanical properties of aniline-doped ...

    African Journals Online (AJOL)

    The effects of Electro-mechanical properties of doped polyester fabric with aniline were investigated. The effects of various concentrations on the electrical as well as mechanical were examined and the percolation threshold was established. Chemical polymerization of aniline on Polyester in hydrochloric acid using ...

  8. Modeling of the Electro-Mechanical Response of Carbon Nanotubes: Molecular Dynamics and Transport Calculations

    Science.gov (United States)

    Svizhenko, Alexel; Anantram, M. P.; Maiti, Amitesh

    2003-01-01

    This paper presents viewgraphs on the modeling of the electromechanical response of carbon nanotubes, utilizing molecular dynamics and transport calculations. The topics include: 1) Simulations of the experiment; 2) Effect of diameter, length and temperature; and 3) Study of sp3 coordination-"The Table experiment".

  9. A novel implantable electromechanical ventricular assist device - First acute animal testing

    NARCIS (Netherlands)

    Kaufmann, R; Rakhorst, G; Mihaylov, D; Elstrodt, J; Nix, C; Reul, H; Rau, G

    1997-01-01

    A novel ventricular assist device (HIA-EMLVAD-AT1, Helmholtz Institute Aachen-electromechanical Left Ventricular Assist Device-Animal Test Version 1), driven by a uniformly and unidirectionally rotating actuator and a patented hypocycloidic pusherplate displacement gear unit, was developed and

  10. A methodology for identification and control of electro-mechanical actuators

    Directory of Open Access Journals (Sweden)

    Tarek A. Tutunji

    2015-01-01

    Simulated and experimental results for two case studies, induction motor and vehicle drive system, are presented in order to validate the proposed methodology. These results showed that electromechanical actuators can be identified and controlled using an easy-to-duplicate and flexible procedure.

  11. A methodology for identification and control of electro-mechanical actuators.

    Science.gov (United States)

    Tutunji, Tarek A; Saleem, Ashraf

    2015-01-01

    Mechatronic systems are fully-integrated engineering systems that are composed of mechanical, electronic, and computer control sub-systems. These integrated systems use electro-mechanical actuators to cause the required motion. Therefore, the design of appropriate controllers for these actuators are an essential step in mechatronic system design. In this paper, a three-stage methodology for real-time identification and control of electro-mechanical actuator plants is presented, tested, and validated. First, identification models are constructed from experimental data to approximate the plants' response. Second, the identified model is used in a simulation environment for the purpose of designing a suitable controller. Finally, the designed controller is applied and tested on the real plant through Hardware-in-the-Loop (HIL) environment. The described three-stage methodology provides the following practical contributions: •Establishes an easy-to-follow methodology for controller design of electro-mechanical actuators.•Combines off-line and on-line controller design for practical performance.•Modifies the HIL concept by using physical plants with computer control (rather than virtual plants with physical controllers). Simulated and experimental results for two case studies, induction motor and vehicle drive system, are presented in order to validate the proposed methodology. These results showed that electromechanical actuators can be identified and controlled using an easy-to-duplicate and flexible procedure.

  12. Kernel parameter variation-based selective ensemble support vector data description for oil spill detection on the ocean via hyperspectral imaging

    Science.gov (United States)

    Uslu, Faruk Sukru

    2017-07-01

    Oil spills on the ocean surface cause serious environmental, political, and economic problems. Therefore, these catastrophic threats to marine ecosystems require detection and monitoring. Hyperspectral sensors are powerful optical sensors used for oil spill detection with the help of detailed spectral information of materials. However, huge amounts of data in hyperspectral imaging (HSI) require fast and accurate computation methods for detection problems. Support vector data description (SVDD) is one of the most suitable methods for detection, especially for large data sets. Nevertheless, the selection of kernel parameters is one of the main problems in SVDD. This paper presents a method, inspired by ensemble learning, for improving performance of SVDD without tuning its kernel parameters. Additionally, a classifier selection technique is proposed to get more gain. The proposed approach also aims to solve the small sample size problem, which is very important for processing high-dimensional data in HSI. The algorithm is applied to two HSI data sets for detection problems. In the first HSI data set, various targets are detected; in the second HSI data set, oil spill detection in situ is realized. The experimental results demonstrate the feasibility and performance improvement of the proposed algorithm for oil spill detection problems.

  13. Phase-chronometric measuring systems for the provision of technological processes and diagnostics of the production of electromechanical engineering systems

    Directory of Open Access Journals (Sweden)

    Tumakova Ekaterina

    2017-01-01

    Full Text Available In paper the main problems and objectives assessment of the current technical condition of the machine-building equipment are considered. Modern measuring systems used in engineering analysis. The paper considers a phase-chronometric information technology-metrological support for the evaluation of the technical condition of the synchronous electromechanical systems on the example of turbine CHP. Analysis of the main problems in the diagnosis of electromechanical systems is given. Phase-chronometric method as a basis for building a new system of diagnosis of electromechanical systems reviewed. The paper describes the main elements of technology, assessment of the economic effects of its introduction in the industry.

  14. Corneal Biomechanical and Anterior Chamber Parameters Variations after 1-year of Transepithelial Corneal Collagen Cross-linking in Eyes of Children with Keratoconus.

    Science.gov (United States)

    Salman, Abdelrahman Gaber

    2016-01-01

    To assess the changes in corneal hysteresis (CH) and corneal resistance factor (CRF) 1-year following transepithelial corneal collagen cross-linking (CXL) treatment in eyes of children with keratoconus. This case series was conducted in 22 eyes of 22 children. Children aged Corneal biomechanical and anterior chamber parameters such as CH, CRF, and peak 1 were noted using ocular response analyzer, Pentacam, intraocular lens master, and anterior segment optical coherence tomography before and 1, 3, 6, and 12 months after treatment. Our series had 22 eyes of 22 children with a mean age 15.7 ± 2.1 years. The CH and CRF 1-year after treatment declined (difference of mean 0.1 mmHg (95% confidence interval [CI] 0.04-0.24), P = 0.2] and (difference of mean 0.1 mmHg [95% CI 0.04-0.30], P = 0.3), respectively. Peak 1 and peak 2 increased (difference of mean 0.1 mmHg [95% CI 0.006-0.008], P = 0.2) and (difference of mean 0.1 mmHg [95% CI 0.007-0.006], P = 0.3), respectively. The uncorrected distance visual acuity improved from 0.95 ± 0.34 logMAR to 0.68 ± 0.45 logMAR (P corneal volume, anterior chamber volume, and anterior chamber depth (P > 0.05). Transepithelial CXL in keratoconus in pediatric age group seems to have good stability in corneal biomechanical parameters after 1-year. Further studies with a larger sample and better study design are recommended to confirm our findings.

  15. Upper crust seismic anisotropy study and temporal variations of shear-wave splitting parameters in the western Gulf of Corinth (Greece) during 2013

    Science.gov (United States)

    Kaviris, George; Spingos, Ioannis; Kapetanidis, Vasileios; Papadimitriou, Panayotis; Voulgaris, Nicholas; Makropoulos, Kostas

    2017-08-01

    During 2013, the Western Gulf of Corinth (WGoC, Central Greece) experienced a period of increased seismicity, with a total of over 4700 earthquakes. This fact in combination with the existence of dense seismological networks provided an excellent opportunity for the study of crustal seismic anisotropy. Of special note is the seismic crisis period of May-October, during which the main feature was the occurrence of the Helike seismic swarm. Polarigrams and hodograms were employed to analyze local waveforms. This method resulted in 659 measurements of shear-wave splitting parameters, namely the direction of the fast shear-wave (Sfast), the time-delay (Td) between the two split shear-waves and the source polarization direction. A pattern of a general WNW-ESE anisotropy direction, parallel to the GoC's fault systems' strike, is established, with the exception of two stations located in adjacent areas at the north. This is in agreement with the existence of fluid-filled microcracks, oriented according to the regional stress field. The obtained splitting parameters are compared to the results of other anisotropy studies performed in the WGoC. A detailed analysis of the temporal evolution of the normalized time-delay (Tn) was performed to associate temporal stress changes to seismicity fluctuations. Increase in normalized time-delays and drop before the occurrence of the first significant event belonging to the ;July Cluster;, which occurred between the 13th and the 16th of the same month, was observed for most of the analyzed stations.

  16. Electromechanical design and construction of a rotating radio-frequency coil system for applications in magnetic resonance.

    Science.gov (United States)

    Trakic, Adnan; Weber, Ewald; Li, Bing Keong; Wang, Hua; Liu, Feng; Engstrom, Craig; Crozier, Stuart

    2012-04-01

    While recent studies have shown that rotating a single radio-frequency (RF) coil during the acquisition of magnetic resonance (MR) images provides a number of hardware advantages (i.e., requires only one RF channel, avoids coil-coil coupling and facilitates large-scale multinuclear imaging), they did not describe in detail how to build a rotating RF coil system. This paper presents detailed engineering information on the electromechanical design and construction of a MR-compatible RRFC system for human head imaging at 2 T. A custom-made (bladeless) pneumatic Tesla turbine was used to rotate the RF coil at a constant velocity, while an infrared optical encoder measured the selected frequency of rotation. Once the rotating structure was mechanically balanced and the compressed air supply suitably regulated, the maximum frequency of rotation measured ~14.5 Hz with a 2.4% frequency variation over time. MR images of a water phantom and human head were obtained using the rotating RF head coil system.

  17. Spatial variation of eco-physiological parameters in the lichen Pseudevernia furfuracea transplanted in an area surrounding a cement plant (S Italy).

    Science.gov (United States)

    Lucadamo, Lucio; Corapi, Anna; Loppi, Stefano; Paoli, Luca; Gallo, Luana

    2015-08-01

    Thalli of the lichen Pseudevernia furfuracea were transplanted for 3 months (November 2010-January 2011) at 61 monitoring sites around a cement plant near Castrovillari (Calabria, southern Italy). NH3, NO x and SO2 concentrations were monitored monthly in a subarea of 10 sites (SA10) where the cement plant was located. At the end of the exposure period, the integrity of cell membranes; membrane lipid peroxidation (thiobarbituric acid reactive substances, TBARS level); vitality (cell respiration); chlorophyll a; chlorophyll b; carotenoids; phaeophytization quotient; photosynthetic efficiency and thalli concentrations of Al, Ca, Mg, V and Fe were measured. NO x concentrations correlated with the site distance from the cement plant while NH3 concentrations correlated with lichen vitality within SA10. For the monitoring area as a whole, only Fe and Mg concentrations correlated with membrane lipid peroxidation, while TBARS levels showed a significant increase and chlorophyll a, chlorophyll b and carotenoids a significant decrease with respect to the lichen origin area. Multivariate analysis (detrended correspondence analysis, cluster analysis and multi-response permutation procedure) of the eco-physiological parameters × monitoring sites data set resulted in four clusters termed C1, C2, C3 and C4. The eco-physiological parameters were compared among the four clusters and lichen origin area by one-way ANOVA. An index of environmental favourableness (IEF) to lichens was calculated to evaluate the spatial recovery of impaired values of TBARS, chlorophyll a, chlorophyll b, xanthophylls + carotenoids and phaeophytization quotient. The results indicate that there is no clear spatial trend in mycobiont impairment even though the IEF values suggest a higher number of sites with low levels of membrane lipid peroxidation in the 2--3-km distance band from the cement plant (the outermost) than in the two other distance bands (0-1 and 1-2 km). The photobiont seems to be

  18. Mesoscale, Radiometrically Referenced, Multi-Temporal Hyperspectral Data for Co2 Leak Detection by Locating Spatial Variation of Biophysically Relevant Parameters

    Science.gov (United States)

    McCann, Cooper Patrick

    Low-cost flight-based hyperspectral imaging systems have the potential to provide valuable information for ecosystem and environmental studies as well as aide in land management and land health monitoring. This thesis describes (1) a bootstrap method of producing mesoscale, radiometrically-referenced hyperspectral data using the Landsat surface reflectance (LaSRC) data product as a reference target, (2) biophysically relevant basis functions to model the reflectance spectra, (3) an unsupervised classification technique based on natural histogram splitting of these biophysically relevant parameters, and (4) local and multi-temporal anomaly detection. The bootstrap method extends standard processing techniques to remove uneven illumination conditions between flight passes, allowing the creation of radiometrically self-consistent data. Through selective spectral and spatial resampling, LaSRC data is used as a radiometric reference target. Advantages of the bootstrap method include the need for minimal site access, no ancillary instrumentation, and automated data processing. Data from a flight on 06/02/2016 is compared with concurrently collected ground based reflectance spectra as a means of validation achieving an average error of 2.74%. Fitting reflectance spectra using basis functions, based on biophysically relevant spectral features, allows both noise and data reductions while shifting information from spectral bands to biophysical features. Histogram splitting is used to determine a clustering based on natural splittings of these fit parameters. The Indian Pines reference data enabled comparisons of the efficacy of this technique to established techniques. The splitting technique is shown to be an improvement over the ISODATA clustering technique with an overall accuracy of 34.3/19.0% before merging and 40.9/39.2% after merging. This improvement is also seen as an improvement of kappa before/after merging of 24.8/30.5 for the histogram splitting technique

  19. Application of the IRI model to the HF propagation model with optimization of the ionosphere parameters to day-to-day variation

    Science.gov (United States)

    Zaalov, N. Y.; Moskaleva, E. V.; Burmakina, T. S.

    2017-11-01

    The HF propagation model, North Ionospheric Model and Ray Tracing (NIM-RT) was developed and tested for a number of years by comparing measured vertical and oblique ionograms over a number of radio links (especially in high latitude area) with the simulated ionograms. The present paper extends the model in order to include: Implementation of the data retrieved from the International Reference Ionosphere (IRI-2012) model into the software for radio channel modeling. The algorithm for IRI data optimization to the real time condition. Results of comparison between simulated and measured ionograms. Based on these updates, a new software tool called North Ionospheric Model with IRI and Ray Tracing (NIMIRI-RT) was developed, and a number of vertical ionograms corresponding to multiple ionospheric reflections was simulated. The vertical ionograms observed at various ionosondes were compared with the synthesized ionograms, generated by applying NIM-RT in conjunction with initial and optimized IRI data. The ionogram structure simulated by NIMIRI-RT based on the data retrieved from optimized IRI is more reminiscent to the observations than ionograms synthesized with the initial NIMIRI-RT without parameters optimization.

  20. Long–term variation of demographic parameters in four small game species in Europe: opportunities and limits to test for a global pattern

    Directory of Open Access Journals (Sweden)

    Gée, A.

    2018-01-01

    Full Text Available For decades, decreases in several populations of some small sedentary game species have been reported in Europe. From the literature, we extracted mortality and reproductive rates that were available for European populations in four iconic species, the grey partridge (Perdix perdix, the black grouse (Tetrao tetrix, the capercaillie (T. urogallus and the brown hare (Lepus europaeus, to examine how demographic parameters vary with time. Our study revealed the need to consider many confounding factors (age, sex, origin of studied individuals, season, country and methods and the scarcity of recent demographic studies. Statistical analyses showed contrasted patterns of demographic traits with time within and between species. Our results highlighted that there may be consistency with a population decrease in grey partridge and black grouse that has been reported in the literature. However, analyses in capercaillie and brown hare showed less support for a population decrease at the European scale. The significant effects of interactions between time and age (in grey partridge, capercaillie and brown hare, method or origin of individuals on demographic traits and the emergence of contrasted patterns between short, intermediate and long monitoring periods (in grey partridge and black grouse suggested that further studies should pay particular attention to potential confounding factors. Finally, the lack of recent data and doubts about the relative importance of reported causal factors indicate the need for further studies on the links between demographic traits, densities and environmental changes in the long term, and particularly on the role of predation and habitat change.

  1. Development experience and development prospect оf electromechanical technological complexes of movement and positioning of technic shelf development equipment

    Directory of Open Access Journals (Sweden)

    А. Е. Козярук

    2016-11-01

    Full Text Available From the example of active semisubmersible drilling rigs it is shown characteristics of electromechanical complexes of drill rigs and anchor position control systems on the base of controlled electric drive with directcurrent motors. It is presented suggestions which allow increasing electric power and service reliability criteria through the use of semiconductor converters supplied from power semiconductor converter with active front end in technological drilling systems, propulsion and position control systems of electromechanical systems on the base of noncontact asynchronous motors. It is outlined information about experience of using such kind of electromechanical complexes at the objects of mining industry working in difficult operating conditions. It is presented information about developing of electromechanical complexes of displacement systems, position control systems, technological and technical shelf development equipment and their characteristics. Also it is outlined structures and examples of designing modern high efficiency systems with contactless actuating motors.

  2. Variation of T c, lattice parameter and atomic ordering in Nb3Sn platelets irradiated with 12 MeV protons: correlation with the number of induced Frenkel defects

    Science.gov (United States)

    Flükiger, R.; Spina, T.; Cerutti, F.; Ballarino, A.; Scheuerlein, C.; Bottura, L.; Zubavichus, Y.; Ryazanov, A.; Svetogovov, R. D.; Shavkin, S.; Degtyarenko, P.; Semenov, Y.; Senatore, C.; Cerny, R.

    2017-05-01

    Nb3Sn platelets with thicknesses between 0.12 and 0.20 mm produced by a high isostatic pressure process at 1250 °C were irradiated at 300 K with 12 MeV protons. The effects of irradiation on the lattice parameter a, the atomic order parameter S and the transition temperature T c were measured as a function of proton fluence. In view of the presence of multiple energy radiation sources in future accelerators, the present proton data are compared with neutron irradiation data from the literature. The fluences for both types of radiation were replaced by the dpa number, the ‘displacements per atom’, calculated using the FLUKA code, which is proportional to the number of radiation induced Frenkel defects. It was found that the variation of both a and S for Nb3Sn after proton and neutron irradiation as a function of dpa fall almost on the same curve, in analogy to the recently reported correlation between T c and the dpa number. By a simultaneous irradiation of two adjacent thin Nb3Sn platelets, we have shown that this correlation is not only valid for the state of ‘steady energy loss’ (protons traveling through the first platelet) but also for the state of higher damage at the Bragg peak (second platelet). It follows that the number of radiation induced Frenkel defects in the A15 grains, calculated via the dpa number, can be considered as a ‘universal’ parameter, allowing the calculation of the variation of T c, a and S of Nb3Sn under the effect of multiple high energy radiation sources, as in future superconducting accelerators.

  3. Towards a physics-based multiscale modelling of the electro-mechanical coupling in electro-active polymers

    OpenAIRE

    Cohen, Noy; Menzel, Andreas; deBotton, Gal

    2016-01-01

    Owing to the increasing number of industrial applications of electro-active polymers (EAPs), there is a growing need for electromechanical models which accurately capture their behaviour. To this end, we compare the predicted behaviour of EAPs undergoing homogeneous deformations according to three electromechanical models. The first model is a phenomenological continuum-based model composed of the mechanical Gent model and a linear relationship between the electric field and the polarization....

  4. Effect of the solar wind and interplanetary magnetic field parameter variations to the enhancement and dynamics of auroral electrojet during superstrong magnetic storms

    Science.gov (United States)

    Solovyev, Stepan; Boroev, Roman; Moiseyev, Alexey; Du, Aimin; Yumoto, Kiyohumi

    According to the global ground geomagnetic observations in the six meridian chains and analysis of satellite measurements the auroral elektrojet features at various conditions in the solar wind (SW) and the IMF: during a sharp rise of dynamic pressure up to 15-60 nPa and variations in the intensity and sign of the IMF Bz-component to -40 --50 nT. The data obtained during super strong magnetic storms of October 29-30, 2003, November 20-21, 2003, November 07-08, 2004 and November 09-10, 2004 (Dst = -300 --400 nT) are analysed. The following scientific results are obtained: • It is shown that a sharp increase of the SW dynamic pressure (Pd) and the excitation of a sudden impulse (SC) during IMF Bz negative (Bzcurrent system and the intensity of the western elec-trojet (Jw) in a broad sector of longitudes and expansion of Jw to the pole up to the polar cap latitudes with the velocity of VN = 1-3 km/s. • It is found that during the sharp rise of Pd up to 60 nPa for IMF Bz positive (Bz>0) 35 nT is the amplification of eastward magnetopause currents and DP2 current system are observed. Strengthening and dynamics of the westward electrojet is not observed. • We find that during periods of intensity growth of negative values of IMF Bz to -50 nT within a few hours there is a shift of the centers of auroral electrojet to the equator up to latitudes about 10-20 degrees along the meridian with a speed of 1-4 km/s with a simultaneous amplifications of Jw repeated in 1-2 hours with a duration of 1-2 hours at latitudes from low to auroral latitudes and with a possible extension to electrojets up to the polar cap latitudes and the abrupt extension of the subsequent Jw electrojets localization region by azimuth. • It is shown that after the electrojet displacement to the equator during southward direc-tion of IMF Bz and enhancement of the SW electric field the IMF Bz turning to the north accompanied by the poleward expansion of Jw electrojet at a speed of 1 km/s in a wide

  5. Atmospheric polycyclic aromatic hydrocarbons in an industrialized city, Kocaeli, Turkey: study of seasonal variations, influence of meteorological parameters and health risk estimation.

    Science.gov (United States)

    Gaga, Eftade O; Ari, Akif; Döğeroğlu, Tuncay; Çakırca, E Emel; Machin, Nesrin E

    2012-08-01

    Ambient gas and particle phase samples were collected during two sampling periods from a residential area of an industrialized city, Kocaeli, Turkey. The sampling occurred during winter months when structures were being heated, and summer months when structures were not being heated. Σ(13)PAH (gas + particle) concentrations ranged between 6.2 ng m(-3) (DahA) and 98.6 ng m(-3) (Phe) in the heating (winter) period and 3.0 ng m(-3) (BaA) and 35.1 ng m(-3) (Phe) in the non-heating (summer) period. Phe, Flt and Pyr were found to be at high concentrations in both sampling periods. Winter time to summer time concentration ratios for individual ambient PAH concentration ratios ranged between 1.2 (DahA) and 17.5 (Flu), indicating the effect of the emissions from residential heating on measured concentrations of PAHs, but great industrial plants and the only incinerator facility of Turkey are other important pollution sources around the city. Temperature dependence of gas phase PAHs was investigated using the Clausius-Clapeyron equation. A high slope obtained (5069.7) indicated the effect of the local sources on measured gas phase PAHs. Correlation of the supercooled vapor pressure (P) with the gas particle partitioning coefficient (K(p)) and particle phase fraction was also evaluated. The relationship between the meteorological parameters and individual PAH (gas + particle) concentrations was investigated further by multiple linear regression analysis. It was found that the temperature had a significant effect on all of the measured PAH concentrations, while the effects of the wind speed and direction were not significant on the individual PAHs. On the other hand, PAH concentrations showed a strong linear relationship with the ventilation coefficient (VC) which showed the influence of local sources on measured PAHs. Benzo[a]pyrene toxic equivalent (BaP(eq.)) concentrations were used for health risk assessment purposes. The winter period risk level (2.92 × 10(-3)) due to

  6. Personalization of cardiac motion and contractility from images using variational data assimilation.

    Science.gov (United States)

    Delingette, Herve; Billet, Florence; Wong, Ken C L; Sermesant, Maxime; Rhode, Kawal; Ginks, Matthew; Rinaldi, C Aldo; Razavi, Reza; Ayache, Nicholas

    2012-01-01

    Personalization is a key aspect of biophysical models in order to impact clinical practice. In this paper, we propose a personalization method of electromechanical models of the heart from cine-MR images based on the adjoint method. After estimation of electrophysiological parameters, the cardiac motion is estimated based on a proactive electromechanical model. Then cardiac contractilities on two or three regions are estimated by minimizing the discrepancy between measured and simulation motion. Evaluation of the method on three patients with infarcted or dilated myocardium is provided. © 2011 IEEE

  7. Design and finite element method analysis of laterally actuated multi-value nano electromechanical switches

    KAUST Repository

    Kloub, Hussam

    2011-09-01

    We report on the design and modeling of novel nano electromechanical switches suitable for implementing reset/set flip-flops, AND, NOR, and XNOR Boolean functions. Multiple logic operations can be implemented using only one switching action enabling parallel data processing; a feature that renders this design competitive with complementary metal oxide semiconductor and superior to conventional nano-electromechanical switches in terms of functionality per device footprint. The structural architecture of the newly designed switch consists of a pinned flexural beam structure which allows low strain lateral actuation for enhanced mechanical integrity. Reliable control of on-state electrical current density is achieved through the use of metal-metal contacts, true parallel beam deflection, and lithographically defined contact area to prevent possible device welding. Dynamic response as a function of device dimensions numerically investigated using ANSYS and MatLab Simulink. © 2011 The Japan Society of Applied Physics.

  8. Opto-Electromechanical Devices for Low-Noise Detection of Radio Waves

    DEFF Research Database (Denmark)

    Bagci, Tolga

    coated membrane and an LC circuit (at ≈ 0.7 MHz). We have characterized the electromechanical coupling by both optical and electrical means, along with the observation of mechanically induced transparency and normal mode splitting due to strong coupling. Finally, we have analyzed the noise performance......There is currently an increasing interest in developing hybrid devices that unite the desirable features of different systems. Opto-electromechanics has emerged as one of these promising hybrid fields, where the functionality of conventional electrical circuits can be combined with the salient...... factors. For example, a hybrid system like this, would enable the use of well-established shot-noise limited optical sensing technologies for detecting weak radio-frequency (rf) signals, rf-to-optical photon conversion and transmission of information in low-loss fiber-optic links over long distances...

  9. Electromechanical and Dynamic Characterization of In-House-Fabricated Amplified Piezo Actuator

    Directory of Open Access Journals (Sweden)

    P. K. Panda

    2012-01-01

    Full Text Available A diamond-shaped amplified piezo actuator (APA fabricated using six multilayered piezo stacks with maximum displacement of 173 μm at 175 V and the amplification factor of 4.3. The dynamic characterization of the actuator was carried out at different frequencies (100 Hz–1 kHz and at different AC voltages (20 V–40 V. The actuator response over this frequency range was found neat, without attenuation of the signal. Numerical modeling of multilayered stack actuator was carried out using empirical equations, and the electromechanical analysis was carried out using ABAQUS software. The block force of the APA was 81 N, calculated by electromechanical analysis. This is similar to that calculated by dynamic characterization method.

  10. On non-linear dynamics of a coupled electro-mechanical system

    DEFF Research Database (Denmark)

    Darula, Radoslav; Sorokin, Sergey

    2012-01-01

    , for mechanical system, is of the second order. The governing equations are coupled via linear and weakly non-linear terms. A classical perturbation method, a method of multiple scales, is used to find a steadystate response of the electro-mechanical system exposed to a harmonic close-resonance mechanical......Electro-mechanical devices are an example of coupled multi-disciplinary weakly non-linear systems. Dynamics of such systems is described in this paper by means of two mutually coupled differential equations. The first one, describing an electrical system, is of the first order and the second one...... excitation. The results are verified using a numerical model created in MATLAB Simulink environment. Effect of non-linear terms on dynamical response of the coupled system is investigated; the backbone and envelope curves are analyzed. The two phenomena, which exist in the electro-mechanical system: (a...

  11. Higher-order nonlinear electromechanical effects in wurtzite GaN/AlN quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Bahrami-Samani, Mehrdad; Patil, Sunil R; Melnik, Roderick, E-mail: mbahrami@wlu.c, E-mail: spatil@wlu.c, E-mail: rmelnik@wlu.c [M2NeT Laboratory, Wilfrid Laurier University, 75 University Avenue W, Waterloo, ON, N2L 3C5 (Canada)

    2010-12-15

    As we demonstrated earlier, conventional mathematical models based on linear approximations may be inadequate in the analysis of properties of low-dimensional nanostructures and band structure calculations. In this work, a general three-dimensional axisymmetric coupled electromechanical model accounting for lattice mismatch, spontaneous polarization and higher-order nonlinear electrostriction effects has been applied to analyze properties of GaN/AlN quantum dots coupled with wetting layer. The generalized model that accounts for five independent electrostriction coefficients has been solved numerically via a finite-element implementation. The results, exemplified for truncated conical GaN/AlN quantum dots, demonstrate that the effect of nonlinear electrostriction in GaN/AlN nanoheterostructure quantum dots could be significant. In particular, the influence of nonlinear electromechanical effects on optoelectronic properties is highlighted by the results on band structure calculations based on a multiband effective mass theory.

  12. Chaos and Adaptive Control of the Fractional-Order Magnetic-Field Electromechanical Transducer

    Science.gov (United States)

    Luo, Shaohua; Li, Shaobo; Tajaddodianfar, Farid

    2017-12-01

    In this paper, we investigate chaos and adaptive control of the magnetic-field electromechanical transducer wherein the electric characteristics of the capacitor contain the fractional-order derivative. The phase diagrams for different values of the fractional-order exhibit chaotic characteristics of the magnetic-field electromechanical transducer. In the process of controller design, a continuous frequency distributed model is utilized to construct the indirect Lyapunov stability criterion and a Chebyshev neural network with weight, and fractional-order adaptive law is introduced to approximate the complicated unknown function. To suppress chaotic oscillation, an adaptive control scheme by fusing Chebyshev neural network and backstepping is presented to guarantee that the closed-loop system is globally asymptotically stable. To illustrate the feasibility of the proposed approach, simulation studies are done in the end.

  13. Non-resonant electromechanical energy harvesting using inter-ferroelectric phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Pérez Moyet, Richard; Rossetti, George A., E-mail: george.rossetti-jr@uconn.edu [Department of Materials Science and Engineering and Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States); Stace, Joseph; Amin, Ahmed [Sensors and Sonar Systems Department, Naval Undersea Warfare Center Newport, Newport, Rhode Island 02841 (United States); Finkel, Peter [Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2015-10-26

    Non-resonant electromechanical energy harvesting is demonstrated under low frequency excitation (<50 Hz) using [110]{sub C}-poled lead indium niobate-lead magnesium niobate-lead titanate relaxor ferroelectric single crystals with compositions near the morphotropic phase boundary. The efficiency of power generation at the stress-induced phase transition between domain-engineered rhombohedral and orthorhombic ferroelectric states is as much as four times greater than is obtained in the linear piezoelectric regime under identical measurement conditions but during loading below the coercive stress of the phase change. The phase transition mode of electromechanical transduction holds potential for non-resonant energy harvesting from low-frequency vibrations and does not require mechanical frequency up-conversion.

  14. In silico investigation of the short QT syndrome, using human ventricle models incorporating electromechanical coupling

    Directory of Open Access Journals (Sweden)

    Ismail eAdeniran

    2013-07-01

    Full Text Available Introduction Genetic forms of the Short QT Syndrome (SQTS arise due to cardiac ion channel mutations leading to accelerated ventricular repolarisation, arrhythmias and sudden cardiac death. Results from experimental and simulation studies suggest that changes to refractoriness and tissue vulnerability produce a substrate favourable to re-entry. Potential electromechanical consequences of the SQTS are less well understood. The aim of this study was to utilize electromechanically coupled human ventricle models to explore electromechanical consequences of the SQTS. Methods and results: The Rice et al. mechanical model was coupled to the ten Tusscher et al. ventricular cell model. Previously validated K+ channel formulations for SQT variants 1 and 3 were incorporated. Functional effects of the SQTS mutations on transients, sarcomere length shortening and contractile force at the single cell level were evaluated with and without the consideration of stretch activated channel current (Isac. Without Isac, the SQTS mutations produced dramatic reductions in the amplitude of transients, sarcomere length shortening and contractile force. When Isac was incorporated, there was a considerable attenuation of the effects of SQTS-associated action potential shortening on Ca2+ transients, sarcomere shortening and contractile force. Single cell models were then incorporated into 3D human ventricular tissue models. The timing of maximum deformation was delayed in the SQTS setting compared to control. Conclusion: The incorporation of Isac appears to be an important consideration in modelling functional effects of SQT 1 and 3 mutations on cardiac electro-mechanical coupling. Whilst there is little evidence of profoundly impaired cardiac contractile function in SQTS patients, our 3D simulations correlate qualitatively with reported evidence for dissociation between ventricular repolarization and the end of mechanical systole.

  15. Electromechanical characterization of piezoelectric actuators subjected to a variable pre-loading force at cryogenic temperature

    Energy Technology Data Exchange (ETDEWEB)

    Fouaidy, M.; Saki, M.; Hammoudi, N.; Simonet, L. [IPN, CNRS-IN2P3, Orsay (France)

    2007-07-01

    A dedicated apparatus was designed and constructed for studying the electromechanical behavior of prototype piezoelectric actuators subjected to a variable pre-loading force at cryogenic temperatures. This device was successfully used for testing a piezoelectric actuator of PICMA type from PI{sup TM}, for T in the range 2 K-300 K. The dielectric properties as well as dynamic properties were measured including the actuator characteristics when used as force sensor. The corresponding data are reported and discussed. (authors)

  16. Lead-free BNT-based composite materials: enhanced depolarization temperature and electromechanical behavior.

    Science.gov (United States)

    Bai, Wangfeng; Zheng, Peng; Wen, Fei; Zhang, Jingji; Chen, Daqin; Zhai, Jiwei; Ji, Zhenguo

    2017-11-14

    The development of (Bi0.5Na0.5)TiO3-based solid solutions with both high depolarization temperature Td and excellent piezoelectric and electromechanical properties for practical application is intractable because improved thermal stability is usually accompanied by a deterioration in piezoelectric and electromechanical performance. Herein, we report a 0-3 type 0.93(Bi0.5Na0.5)TiO3-0.07BaTiO3 : 30 mol%ZnO composite (BNT-7BT : 0.3ZnO), in which the ZnO nanoparticles exist in two forms, to resolve the abovementioned long-standing obstacle. In this composite, Zn ions fill the boundaries of BNT-7BT grains, and residual Zn ions diffuse into the BNT-7BT lattice, as confirmed by XRD, Raman spectroscopy, and microstructure analysis. The BNT-7BT composite ceramics with a 0-3 type connectivity exhibited enhanced frequency-dependent electromechanical properties, fatigue characteristics, and thermal stabilities. More importantly, low poling field-driven large piezoelectric properties were observed for the composite ceramics as compared to the case of the pure BNT-7BT solid solution. A mechanism related to the ZnO-driven phase transition from the rhombohedral to tetragonal phase and built-in electric field to partially compensate the depolarization field was proposed to explain the achieved outstanding piezoelectric performance. This is the first time that the thermal stability, electromechanical behavior, and low poling field-driven high piezoelectric performance of BNT-based ceramics have been simultaneously optimized. Thus, our study provides a referential methodology to achieve novel piezoceramics with excellent piezoelectricity by composite engineering and opens up a new development window for the utilization of conventional BNT-based and other lead-free ceramics in practical applications.

  17. Modernization of the Grinding Electromechanical Drive System of the Automated Coffee Machine

    OpenAIRE

    Ilie Nuca; Adrian Țurcanu

    2014-01-01

    The paper refers to espresso coffee machines high quality and some possibilities to increase the level of automation and productivity. Existing machines require manual adjustment of coffee grinder depending on the quality of coffee beans. To eliminate this flaw has been developed and implemented an adjustable electromechanical system with DC servomotor and numerical control of coffee grinder. Computer simulation results demonstrate the functionality of the proposed electrome...

  18. Predictive modeling of composite material degradation using piezoelectric wafer sensors electromechanical impedance spectroscopy

    Science.gov (United States)

    Gresil, Matthieu; Yu, Lingyu; Sutton, Mike; Guo, Siming; Pollock, Patrick

    2012-04-01

    The advancement of composite materials in aircraft structures has led to on increased need for effective structural health monitoring (SHM) technologies that are able to detect and assess damage present in composites structures. The work presented in this paper is interested in understanding using self-sensing piezoelectric wafer active sensors (PWAS) to conduct electromechanical impedance spectroscopy (EMIS) in glass fiber reinforced plastic (GFRP) to perform structures health monitoring. PWAS are bonded to the composite material and the EMIS method is used to analyze the changes in the structural resonance and anti-resonance. As the damage progresses in the specimen, the impedance spectrum will change. In addition, multi-physics based finite element method (MP-FEM) is used to model the electromechanical behavior of a free PWAS and its interaction with the host structure on which it is bonded. The MPFEM permits the input and the output variables to be expressed directly in electric terms while the two way electromechanical conversion is done internally in the MP_FEM formulation. To reach the goal of using the EMIS approach to detect damage, several damages models are generated on laminated GFRP structures. The effects of the modeling are carefully studied through experimental validation. A good match has been observed for low and very high frequencies.

  19. Atrial electromechanical cycle length mapping in paced canine hearts in vivo.

    Science.gov (United States)

    Costet, Alexandre; Bunting, Ethan; Grondin, Julien; Gambhir, Alok; Konofagou, Elisa E

    2015-07-01

    Atrial arrhythmias affect millions of people worldwide. Characterization and study of arrhythmias in the atria in the clinic is currently performed point by point using mapping catheters capable of generating maps of the electrical activation rate or cycle length. In this paper, we describe a new ultrasound-based mapping technique called electromechanical cycle length mapping (ECLM) capable of estimating the electromechanical activation rate, or cycle length, i.e., the rate of the mechanical activation of the myocardium which follows the electrical activation. ECLM relies on frequency analysis of the incremental strain within the atria and can be performed in a single acquisition. ECLM was validated in a canine model paced from the left atrial appendage, against pacing rates within the reported range of cycle lengths previously measured during atrial arrhythmias such as atrial fibrillation. Correlation between the global estimated electromechanical cycle lengths and pacing rates was shown to be excellent (slope = 0.983, intercept = 3.91, r(2) = 0.9999). The effect of the number of cardiac cycles on the performance of ECLM was also investigated and the reproducibility of ECLM was demonstrated (error between consecutive acquisitions for all pacing rates: 6.3 ± 4.3%). These findings indicate the potential of ECLM for noninvasively characterizing atrial arrhythmias and provide feedback on the treatment planning of catheter ablation procedures in the clinic.

  20. Analysis of the actuating effects of triple-layer piezoelectric cantilevers considering electromechanical coupling correction

    Science.gov (United States)

    Gong, Li Jiao; Pan, Cheng Liang; Pan, Qiao Sheng

    2017-02-01

    A dynamic analytical model is developed to predict the performance of a triple-layer piezoelectric cantilever as actuators in relation to materials with large piezoelectric and electromechanical coupling (EMC) coefficients under axial stress and plane strain conditions. The dynamic electromechanical behavior of a symmetrical triple-layer piezoelectric cantilever (STLPC) actuator is investigated. The analytical model of STLPC based on electromechanical coupling correction coefficient (EMCC) is established in one-dimensional (1D) form and applied to 1D and 2D deformations. Furthermore, the theoretical analysis of the EMCC model is critically evaluated and compared with the simulations using a finite element method (FEM). Results show that the EMCC model can be accurately applied to analyze the actuation performance of STLPC. Analyzed results show that the proposed model is accurately applied to large and small piezoelectric coupling conditions. The piezoelectric cantilever with large piezoelectric and EMC coefficients can be accurately analyzed by the proposed model accounted for small EMC condition in a traditional model. Design optimization based on actuators is also discussed. Optimal thickness ratios between elastic and piezoelectric layers are effectively calculated and obtained.

  1. Electromechanical Battery EMB Mass Minimization taking into Account its Electrical Machines Rotor Energy

    Directory of Open Access Journals (Sweden)

    Podgornovs Andrejs

    2014-12-01

    Full Text Available In this paper the electromechanical battery (EMB with synchronous machine is described. Theoretically, if electrical machines rotor stored energy is known, it is possible to reduce the flywheel mass of electromechanical battery. For example, the efficiency of energy recovery (kilowatt-hours out versus kilowatthours in in nowadays appliances exceeds 95 % which is considerably better than of any electrochemical battery, such as lead-acid battery. For the rotor stored energy amount calculation, it is necessary to find all geometrical dimensions of the electrical machine. To achieve this goal the iterative calculation method was used. Electromechanical battery mass was analyzed as a discharge process rotation speed function. Taking into account the rotor stored energy, we can increase the minimum rotation speed thus reducing the electrical machine mass and increasing the flywheel mass, which provides EMB cost reduction. Additionally, the possibilities of using numerical approximation calculations of magnetization curves are discussed. Each iteration of numerical application necessary for the method for rapid calculation is essential when calculating the field problems. Nowadays there are a lot of computer added design programs for electromagnetic field calculation in different types of applications, electrical machines and apparatus. For the electromagnetic field calculation process some more commonly used magnetization curve approximation methods are described, and the machine calculation time is tested for different numbers of calculations.

  2. Design and Development of Electro-Mechanical Twins Tipping Buckets Runoff-Meter

    Directory of Open Access Journals (Sweden)

    Olotu Yahaya

    2014-07-01

    Full Text Available Electro-mechanical tipping bucket runoff-meter was designed and developed to measure surface runoff water using locally-sourced components. The instrument consists of metallic-fabricated runoff plot area of 2 m 2 , depth 0.25 m and metal gauge of 3mm. The tipping operation was initiated by arranging the sensitive electro-mechanical components such digital micro-switch (SW1,SW2, SW3 and SW4, pair of open/close circuit breakers (No,Nc, electronic speed gear and circular rotating disc to a pair of twins buckets of runoff volume 0.141 liter capacity per bucket which corresponds to 0.25 mm runoff depth. The whole arrangement was powered by a 12V by 75 AH battery and the tipping processes was being recorded by the electro-mechanical data logger. The instrument has a measuring accuracy of ±0.001 liter per tip. It was calibrated to measure minimum and maximum runoff volume from 0.14l to 200 liters, these values correspond to 0.25 mm and 800 mm runoff depths respectively. Therefore, precise results obtained using the instrument could be used to establish strong database for measuring and storing accurate surface runoff data which in turn could be applied for hydrological modeling for sustainable water resources management and design of hydraulic structures

  3. Calculation and measurement of electromechanical coupling coefficient of capacitive micromachined ultrasonic transducers.

    Science.gov (United States)

    Yaralioglu, Goksen G; Ergun, Arif Sanli; Bayram, Baris; Haeggström, Edward; Khuri-Yakub, Butrus T

    2003-04-01

    The electromechanical coupling coefficient is an important figure of merit of ultrasonic transducers. The transducer bandwidth is determined by the electromechanical coupling efficiency. The coupling coefficient is, by definition, the ratio of delivered mechanical energy to the stored total energy in the transducer. In this paper, we present the calculation and measurement of coupling coefficient for capacitive micromachined ultrasonic transducers (CMUTs). The finite element method (FEM) is used for our calculations, and the FEM results are compared with the analytical results obtained with parallel plate approximation. The effect of series and parallel capacitances in the CMUT also is investigated. The FEM calculations of the CMUT indicate that the electromechanical coupling coefficient is independent of any series capacitance that may exist in the structure. The series capacitance, however, alters the collapse voltage of the membrane. The parallel parasitic capacitance that may exist in a CMUT or is external to the transducer reduces the coupling coefficient at a given bias voltage. At the collapse, regardless of the parasitics, the coupling coefficient reaches unity. Our experimental measurements confirm a coupling coefficient of 0.85 before collapse, and measurements are in agreement with theory.

  4. Multiscale simulations of defect dipole-enhanced electromechanical coupling at dilute defect concentrations

    Science.gov (United States)

    Liu, Shi; Cohen, R. E.

    2017-08-01

    The role of defects in solids of mixed ionic-covalent bonds such as ferroelectric oxides is complex. Current understanding of defects on ferroelectric properties at the single-defect level remains mostly at the empirical level, and the detailed atomistic mechanisms for many defect-mediated polarization-switching processes have not been convincingly revealed quantum mechanically. We simulate the polarization-electric field (P-E) and strain-electric field (ɛ-E) hysteresis loops for BaTiO3 in the presence of generic defect dipoles with large-scale molecular dynamics and provide a detailed atomistic picture of the defect dipole-enhanced electromechanical coupling. We develop a general first-principles-based atomistic model, enabling a quantitative understanding of the relationship between macroscopic ferroelectric properties and dipolar impurities of different orientations, concentrations, and dipole moments. We find that the collective orientation of dipolar defects relative to the external field is the key microscopic structure feature that strongly affects materials hardening/softening and electromechanical coupling. We show that a small concentration (≈0.1 at. %) of defect dipoles dramatically improves electromechanical responses. This offers the opportunity to improve the performance of inexpensive polycrystalline ferroelectric ceramics through defect dipole engineering for a range of applications including piezoelectric sensors, actuators, and transducers.

  5. Temporal change in the electromechanical properties of dielectric elastomer minimum energy structures

    Energy Technology Data Exchange (ETDEWEB)

    Buchberger, G., E-mail: erda.buchberger@jku.at; Hauser, B.; Jakoby, B.; Hilber, W. [Institute for Microelectronics and Microsensors, Johannes Kepler University Linz, 4040 Linz (Austria); Schoeftner, J. [Institute of Technical Mechanics, Johannes Kepler University Linz, 4040 Linz (Austria); Bauer, S. [Department of Soft Matter Physics, Johannes Kepler University Linz, 4040 Linz (Austria)

    2014-06-07

    Dielectric elastomer minimum energy structures (DEMES) are soft electronic transducers and energy harvesters with potential for consumer goods. The temporal change in their electromechanical properties is of major importance for engineering tasks. Therefore, we study acrylic DEMES by impedance spectroscopy and by optical methods for a total time period of approx. 4.5 months. We apply either compliant electrodes from carbon black particles only or fluid electrodes from a mixture of carbon black particles and silicone oil. From the measurement data, the equivalent series capacitances and resistances as well as the bending angles of the transducers are obtained. We find that the equivalent series capacitances change in average between −12 %/1000 h and −4.0 %/1000 h, while the bending angles decrease linearly with slopes ranging from −15 %/1000 h to −7 %/1000 h. Transducers with high initial bending angles and electrodes from carbon black particles show the smallest changes of the electromechanical characteristics. The capacitances decrease faster for DEMES with fluid electrodes. Some DEMES of this type reveal huge and unpredictable fluctuations of the resistances over time due to the ageing of the contacts. Design guidelines for DEMES follow directly from the observed transient changes of their electromechanical performance.

  6. Electrical Impedance Spectroscopy for Electro-Mechanical Characterization of Conductive Fabrics

    Directory of Open Access Journals (Sweden)

    Tushar Kanti Bera

    2014-06-01

    Full Text Available When we use a conductive fabric as a pressure sensor, it is necessary to quantitatively understand its electromechanical property related with the applied pressure. We investigated electromechanical properties of three different conductive fabrics using the electrical impedance spectroscopy (EIS. We found that their electrical impedance spectra depend not only on the electrical properties of the conductive yarns, but also on their weaving structures. When we apply a mechanical tension or compression, there occur structural deformations in the conductive fabrics altering their apparent electrical impedance spectra. For a stretchable conductive fabric, the impedance magnitude increased or decreased under tension or compression, respectively. For an almost non-stretchable conductive fabric, both tension and compression resulted in decreased impedance values since the applied tension failed to elongate the fabric. To measure both tension and compression separately, it is desirable to use a stretchable conductive fabric. For any conductive fabric chosen as a pressure-sensing material, its resistivity under no loading conditions must be carefully chosen since it determines a measurable range of the impedance values subject to different amounts of loadings. We suggest the EIS method to characterize the electromechanical property of a conductive fabric in designing a thin and flexible fabric pressure sensor.

  7. Electrical Impedance Spectroscopy for Electro-Mechanical Characterization of Conductive Fabrics

    Science.gov (United States)

    Bera, Tushar Kanti; Mohamadou, Youssoufa; Lee, Kyounghun; Wi, Hun; Oh, Tong In; Woo, Eung Je; Soleimani, Manuchehr; Seo, Jin Keun

    2014-01-01

    When we use a conductive fabric as a pressure sensor, it is necessary to quantitatively understand its electromechanical property related with the applied pressure. We investigated electromechanical properties of three different conductive fabrics using the electrical impedance spectroscopy (EIS). We found that their electrical impedance spectra depend not only on the electrical properties of the conductive yarns, but also on their weaving structures. When we apply a mechanical tension or compression, there occur structural deformations in the conductive fabrics altering their apparent electrical impedance spectra. For a stretchable conductive fabric, the impedance magnitude increased or decreased under tension or compression, respectively. For an almost non-stretchable conductive fabric, both tension and compression resulted in decreased impedance values since the applied tension failed to elongate the fabric. To measure both tension and compression separately, it is desirable to use a stretchable conductive fabric. For any conductive fabric chosen as a pressure-sensing material, its resistivity under no loading conditions must be carefully chosen since it determines a measurable range of the impedance values subject to different amounts of loadings. We suggest the EIS method to characterize the electromechanical property of a conductive fabric in designing a thin and flexible fabric pressure sensor. PMID:24892493

  8. MODELING OF ELECTROMECHANICAL TRANSIENTS IN ASYNCHRONOUS MOTORS BASED ON THE USE OF TCHEBYSHEV’S POLYNOMIALS

    Directory of Open Access Journals (Sweden)

    I. V. Tokmakov

    2015-12-01

    Full Text Available The article is dedicated to development of numerical method of electromechanical transient processes calculation in asynchronous motors. Electromechanical transient processes might be quite continuous that causes the calculation time increase and accumulation of errors due to use of modern software solutions. The aim of this work is to design more accelerated method of calculation of electromechanical transient processes in asynchronous motors and to create the convenient and practical model scheme of method. The method is based on approximation of state equations solution with the help of expansion of the solution with orthogonal Chebyshev’s polynomials. The scheme interpretation of this method is presented; it considers the rotor rotation frequency as some current. The given method allows to substitute operations with momentary values of currents by operations with currents images, which are interpreted as constant currents at equivalent circuit. As the result the initial integro-differential equations of state are substituted by the algebraic equations of current images. Also there is method of calculation of production image of the currents which are present at electrical machine. CPU time is decreased more than twice compared to common methods due to calculation of transient process in asynchronous motor according to the given method. Considered method is convenient for calculations of transient processes in complex circuits that include not only asynchronous motors but other electrical machines

  9. The effect of air pollution on diurnal variation of performance in anaerobic tests, cardiovascular and hematological parameters, and blood gases on soccer players following the Yo-Yo Intermittent Recovery Test Level-1.

    Science.gov (United States)

    Boussetta, Nesrin; Abedelmalek, Salma; Aloui, Khouloud; Souissi, Nizar

    2017-01-01

    This study aimed to investigate the effect of air pollution on diurnal variation of performance in anaerobic tests, cardiovascular and hematological parameters, and blood gases on soccer players following the Yo-Yo Intermittent Recovery Test Level-1 (YYIRT1). In a randomized order, 11 healthy soccer players (mean age: 21.8 [range: 20-24] years; height: 178.00 [range: 1.64-1.83] cm; body mass index [BMI]: 23.57 [range: 20.45-28.03] kg.m-2) performed a YYIRT1 at two different times of day (TOD) (08:00 h and 18:00 h) in two areas (i.e. polluted (PA) and non-polluted (NPA)) with a recovery period of ≥ 72 h in between, to determine the maximal oxygen uptake (VO2max). In each test session: resting oral temperature is measured, anaerobic performances (pre- and post-YYIRT1) were performed, cardiovascular parameters and blood samples were collected at: rest, 3 min and 60 min after the YYIRT1, to assess blood gases and hematological parameters. Our results showed that, agility performance, VO2max, red blood cells (RBC), hemoglobin (Hb), pH, and bicarbonate levels (HCO3-) decrease significantly (p effect was slightly accentuated at 18:00 h for some parameters (i.e. Agility, HCO3-, HR, PvCO2, RBC, SBP). However, performances of sprint and Sargent jump test (SJT), oral temperature, rate of perceived exertion scales (RPE), partial pressure of O2 (PvO2), diastolic blood pressure (DBP), and monocytes (MON) were not affected by pollution (p > 0.05). In conclusion, pollution seems to be critical for health stability and performance in response to YYIRT1 especially in the evening and the winter season. Therefore, coaches and athletes should draw attention to the potential importance of land use planning in their training sessions and competitions in the morning in polluted area to minimize the risk of pollution exposure.

  10. Assessment of atrial electromechanical delay and left atrial mechanical functions in patients with psoriasis vulgaris.

    Science.gov (United States)

    Aksan, Gökhan; Nar, Gökay; Soylu, Korhan; İnci, Sinan; Yuksel, Serkan; Ocal, Hande Serra; Yuksel, Esra Pancar; Gulel, Okan

    2015-04-01

    Increased frequency of atrial fibrillation (AF) has been demonstrated in psoriasis cases. Prolongation of the duration of atrial electromechanical delay (AEMD) is a well-known characteristic of the atrium, which is vulnerable to AF. In the current study, our aims are to investigate AEMD durations and mechanical functions of the left atrium (LA) in patients with psoriasis. A total of 90 patients, 45 with psoriasis vulgaris and 45 as the control group, were included in the study. Atrial electromechanical coupling (PA) and intra- and inter-atrial electromechanical delay (IA-AEMD) were measured with tissue Doppler echocardiography. P-wave dispersion (PWD) was calculated from the 12-lead electrocardiogram. The severity of the disease was evaluated by the Psoriasis Area and Severity Index. The durations of PA lateral and PA septal were significantly high in the psoriasis group when compared with the control group (47.7 ± 9.8 vs. 57.1 ± 8.4 msec, P < 0.001 and 38.6 ± 9.9 vs. 43.6 ± 8 msec, P = 0.016, respectively). The durations of IA-AEMD, intra-right electromechanical delay, and intra-left electromechanical delay in the psoriasis group were significantly prolonged compared with the control group (15.2 ± 4.1 vs. 21.7 ± 5.6 msec, P < 0.001; 6 ± 2.5 vs. 8.7 ± 2.7 msec, P < 0.001; and 9.1 ± 3.9 vs. 13.5 ± 5.2 msec, P < 0.001; respectively). PWD was significantly higher in patients with psoriasis vulgaris compared with controls (36.1 ± 7.9 vs. 40.2 ± 9.1 msec, P = 0.043). In the present study, we found prolongation in the durations of AEMD and PWD in the psoriasis group compared with the control group. These results might be an early predictor of AF and other arrhythmias. © 2014, Wiley Periodicals, Inc.

  11. MATHEMATICAL MODEL OF SEMICONDUCTOR CONVERTER WITH FIVE-ZONE REGULATION OF THE OUTPUT VOLTAGE AND ELECTROMECHANICAL LOAD

    Directory of Open Access Journals (Sweden)

    V. V. Mikhailenko

    2014-02-01

    Full Text Available Purpose. This work is directed on study of the electromagnetic processes in electric circuits with semiconductor commutators. It is necessary to develop the new mathematical models of functions determination and algorithmic equations for analysis of formed and transition processes in electric circuits of the variable structure. To research the mathematical models with semiconductor commutators and sections, in which sine, constant and pulsed voltages appear. Methodology. The mathematical model of the semiconductor converter with electromechanical load was created for achievement the purpose in view. It is shown that appearance of nonlinear element complicates powerfully the problems of the calculation and studies appearing in circuits of the electromagnetic processes. The most complications appear in circuits of the variable structure, in which sine, constant and pulsed current arise under the action of appropriete voltages. Findings. The new mathematical models of the electromagnetic processes were designed in three-phase electric circuit of the semiconductor converters with multiserver zoned regulation of phase voltages (without losses in semiconductor commutators for quick estimation the load parameters influence on level and form of the output voltage. Originality. The method of multi-parameter functions was developed. The last are included in algorithmic equations for analysis of formed and transition processes in network with semiconductor commutators and reactive elements, in the considerations direction of phase to neutral voltages usage in the power circuit. It is motivated that use of the multi-parameter modulating functions method in electric circuit of variable structures is expedient if in their sections there are not more than three independent reactive elements. The new mathematical model of formed and transition processes in electric circuits of the semiconductor converters, modulation type with multiserver zoned use of phase to

  12. Sliding mode control on electro-mechanical systems

    Directory of Open Access Journals (Sweden)

    Utkin Vadim I.

    2002-01-01

    Full Text Available The first sliding mode control application may be found in the papers back in the 1930s in Russia. With its versatile yet simple design procedure the methodology is proven to be one of the most powerful solutions for many practical control designs. For the sake of demonstration this paper is oriented towards application aspects of sliding mode control methodology. First the design approach based on the regularization is generalized for mechanical systems. It is shown that stability of zero dynamics should be taken into account when the regular form consists of blocks of second-order equations. Majority of applications in the paper are related to control and estimation methods of automotive industry. New theoretical methods are developed in the context of these studies: sliding made nonlinear observers, observers with binary measurements, parameter estimation in systems with sliding mode control.

  13. Variations of the ionospheric parameters and vertical electron density distribution at the northern edge of the EIA from 2010 to 2015 along 95°E and comparison with the IRI-2012

    Science.gov (United States)

    Kalita, Bitap Raj; Bhuyan, Pradip Kumar

    2017-07-01

    The vertical electron density profiles over Dibrugarh (27.5°N, 95°E, 43° dip) a low mid latitude station normally located at the northern edge of the EIA for the period of July 2010 till October 2015 are constructed from the measured bottom side profiles and ionosonde-GPS TEC assisted Topside Sounder Model (TSM) topside profiles. The bottom side density profiles are obtained by using POLAN on the manually scaled ionograms. The topside is constructed by the modified ionosonde assisted TSM model (TaP-TSM assisted by POLAN) which is integrated with POLAN for the first time. The reconstructed vertical profile is compared with the IRI predicted density profile and the electron density profile obtained from the COSMIC/FORMOSAT radio occultation measurements over Dibrugarh. The bottom side density profiles are fitted to the IRI bottom side function to obtain best-fit bottom side thickness parameter B0 and shape parameter B1. The temporal and solar activity variation of the B-parameters over Dibrugarh are investigated and compared to those predicted by IRI-2012 model with ABT-2009 option. The bottom side thickness parameter B0 predicted by the IRI model is found to be similar to the B0 measured over Dibrugarh in the night time and the forenoon hours. Differences are observed in the early morning and the afternoon period. The IRI doesn't reproduce the morning collapse of B0 and overestimates the B0 over Dibrugarh in the afternoon period, particularly in summer and equinox. The IRI model predictions are closest to the measured B0 in the winter of low solar activity. The B0 over Dibrugarh is found to increase by about 15% with solar activity during the period of study encompassing almost the first half of solar cycle 24 but solar activity effect was not observed in the B1 parameter. The topside profile obtained from TaP profiler is thicker than the IRI topside in equinox from afternoon to sunrise period but is similar to the IRI in summer daytime. The differences in the

  14. Simulating the parameters of multi-modal groundwater residence-time distributions using parsimonious and automatically generated numerical models that incorporate spatial variation of drainage density, aquifer thickness, recharge, and aquifer properties

    Science.gov (United States)

    Starn, J. J.; Belitz, K.; Kauffman, L. J.; Yager, R. M.

    2016-12-01

    Groundwater residence-time distributions (RTDs) are important for assessing groundwater vulnerability. Two methods for calculating RTDs are common: lumped parameter models (LPMs) and distributed numerical models (DNMs). Model parameters in either approach can be determined by fitting to tracer data. LPMs represent simple flow systems and have few parameters; however, they may not be appropriate where internal aquifer processes are important, in transient flow systems, or in spatially complex flow systems. DNMs are not constrained by assumptions of uniform aquifer thickness, recharge, or aquifer properties, but are time-consuming and expensive to construct. This approach seeks to bridge the gap between LPMs and DNMs. Generalized DNMs (GDNMs) are created having a small number of parameters compared to typical DNMs. GDNMs are created automatically at the HUC8 scale based on nationally available data sets and incorporate spatial variation not present in LPMs such as drainage density, aquifer thickness, recharge, and aquifer properties. Typical creation time from a model domain shapefile to a "calibrated" model is about 10 minutes. GDNMs were created in various hydrogeologic settings in the glaciated U.S. where age-tracer data exist. GDNMs are "calibrated" by automatically adjusting hydraulic conductivity in a small number of zones to minimize the fraction of cells where the simulated water table is above land surface and below perennial streams. RTDs are calculated for groundwater basins, public-supply wells, and stream reaches using particle tracking. RTDs, which often are multi-modal, are summarized by fitting statistical distributions (additive combinations of Weibull, gamma, or inverse Gaussian) to particle RTDs. GDNMs are tested by comparing simulated and observed heads and by applying convolution to generate breakthrough curves for tracers that can be compared to observed concentrations. GDNMs also are compared to highly distributed DNMs from other sources. The

  15. Electromechanical characterization of superconducting wires and tapes at 77 K

    CERN Document Server

    Bjoerstad, Roger

    The strain dependency of the critical current in state-of-the-art cuprate high-temperature superconductors (HTS) has been characterized. A universal test machine (UTM) combined with a critical current measurement system has been used to characterize the mechanical and the superconducting properties of conductors immersed in an open liquid nitrogen dewar. A set-up has been developed in order to perform simultaneous measurements of the superconductor lattice parameter changes, critical current, as well as the stress and strain at 77 K in self-field in a high energy synchrotron beamline. The HTS tapes and wires studied were based on YBCO, Bi-2223 and Bi-2212. The YBCO tapes were produced by SuperPower and American Superconductors (AMSC). Two types of Bi-2223 tapes, HT and G, were produced by Sumitomo Electric Industries (SEI). The Bi-2212 wires were produced by Oxford Superconducting Technology (OST) using Nexans granulate precursor, before undergoing a specialized over pressure (OP) processing and heat treatmen...

  16. Electromechanical impedance-based fault detection in a rotating machine by using an operating condition compensation approach

    Science.gov (United States)

    Tsuruta, K. M.; Rabelo, D. S.; Guimarães, C. G.; Cavalini, A. A.; Finzi Neto, R. M.; Steffen, V.

    2017-04-01

    The electromechanical impedance is a condition-based maintenance (CBM) methodology that uses sensors network to evaluate health condition of mechanical systems. Piezoelectric transducers are used as sensors and actuators to damage detection. Such approach monitors changes in the electric impedance of piezoelectric transducers that are bonded to the host structure. Normally the evaluation of the impedance responses is performed by using damage metrics, which permit to quantify the influence of damage. This is possible since the sensor electrical impedance is directly related to the mechanical impedance of the structure. However, the frequency response functions (FRFs) resulting from this method are susceptible to environmental and operational conditions that must be accounted for in order to avoid false diagnostics. Thus, the aim of this paper relies on the correct detection of incipient faults in rotating shafts under operating condition by using a real-time Impedance-based Structural Health Monitoring (ISHM) method. For this purpose, a data normalization procedure for compensation of changes in environmental and operating conditions is used to minimize changes in impedance signatures resulting from these external influences. Changes on dynamic load result from altering the rotation speed and unbalance level, while temperature changes stem from daily room temperature variations. The compensation technique is based on a hybrid optimization method associated with a given damage metrics. Additionally, a statistical model is used for threshold determination based on the Statistical Process Control (SPC) method. Experimental results show that an incipient damage associated with temperature and dynamic loads effects could be successfully detected with a probability of detection above 95 % confidence for the majority of the sensors used.

  17. Design and fabrication of a flexible MEMS-based electromechanical sensor array for breast cancer diagnosis.

    Science.gov (United States)

    Pandya, Hardik J; Park, Kihan; Desai, Jaydev P

    2015-06-23

    The use of flexible micro-electro-mechanical systems (MEMS) based device provides a unique opportunity in bio-medical robotics such as characterization of normal and malignant tissues. This paper reports on design and development of a flexible MEMS-based sensor array integrating mechanical and electrical sensors on the same platform to enable the study of the change in electro-mechanical properties of the benign and cancerous breast tissues. In this work, we present the analysis for the electrical characterization of the tissue specimens and also demonstrate the feasibility of using the sensor for mechanical characterization of the tissue specimens. Eight strain gauges acting as mechanical sensors were fabricated using poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) conducting polymer on poly(dimethylsiloxane) (PDMS) as the substrate material. Eight electrical sensors were fabricated using SU-8 pillars on gold (Au) pads which were patterned on the strain gauges separated by a thin insulator (SiO2 1.0μm). These pillars were coated with gold to make it conducting. The electromechanical sensors are integrated on the same substrate. The sensor array covers 180μm × 180μm area and the size of the complete device is 20mm in diameter. The diameter of each breast tissue core used in the present study was 1mm and the thickness was 8μm. The region of interest was 200μm × 200μm. Microindentation technique was used to characterize the mechanical properties of the breast tissues. The sensor is integrated with conducting SU-8 pillars to study the electrical property of the tissue. Through electro-mechanical characterization studies using this MEMS-based sensor, we were able to measure the accuracy of the fabricated device and ascertain the difference between benign and cancer breast tissue specimens.

  18. Multi-material micro-electromechanical fibers with bendable functional domains

    Science.gov (United States)

    Nguyen-Dang, Tung; Page, Alexis G.; Qu, Yunpeng; Volpi, Marco; Yan, Wei; Sorin, Fabien

    2017-04-01

    The integration of increasingly complex functionalities within thermally drawn multi-material fibers is heralding a novel path towards advanced soft electronics and smart fabrics. Fibers capable of electronic, optoelectronic, piezoelectric or energy harvesting functions are created by assembling new materials in intimate contact within increasingly complex architectures. Thus far, however, the opportunities associated with the integration of cantilever-like structures with freely moving functional domains within multi-material fibers have not been explored. Used extensively in the micro-electromechanical system (MEMS) technology, electro-mechanical transductance from moving and bendable domains is used in a myriad of applications. In this article we demonstrate the thermal drawing of micro-electromechanical fibers (MEMF) that can detect and localize pressure with high accuracy along their entire length. This ability results from an original cantilever-like design where a freestanding electrically conductive polymer composite film bends under an applied pressure. As it comes into contact with another conducting domain, placed at a prescribed position in the fiber cross-section, an electrical signal is generated. We show that by a judicious choice of materials and electrical connectivity, this signal can be uniquely related to a position along the fiber axis. We establish a model that predicts the position of a local touch from the measurement of currents generated in the 1D MEMF device, and demonstrate an excellent agreement with the experimental data. This ability to detect and localize touch over large areas, curved surfaces and textiles holds significant opportunities in robotics and prosthetics, flexible electronic interfaces, and medical textiles. , which features invited work from the best early-career researchers working within the scope of J. Phys. D. This project is part of the Journal of Physics series’ 50th anniversary celebrations in 2017. Fabien Sorin

  19. Optical Mass Displacement Tracking: A simplified field calibration method for the electro-mechanical seismometer.

    Science.gov (United States)

    Burk, D. R.; Mackey, K. G.; Hartse, H. E.

    2016-12-01

    We have developed a simplified field calibration method for use in seismic networks that still employ the classical electro-mechanical seismometer. Smaller networks may not always have the financial capability to purchase and operate modern, state of the art equipment. Therefore these networks generally operate a modern, low-cost digitizer that is paired to an existing electro-mechanical seismometer. These systems are typically poorly calibrated. Calibration of the station is difficult to estimate because coil loading, digitizer input impedance, and amplifier gain differences vary by station and digitizer model. Therefore, it is necessary to calibrate the station channel as a complete system to take into account all components from instrument, to amplifier, to even the digitizer. Routine calibrations at the smaller networks are not always consistent, because existing calibration techniques require either specialized equipment or significant technical expertise. To improve station data quality at the small network, we developed a calibration method that utilizes open source software and a commonly available laser position sensor. Using a signal generator and a small excitation coil, we force the mass of the instrument to oscillate at various frequencies across its operating range. We then compare the channel voltage output to the laser-measured mass displacement to determine the instrument voltage sensitivity at each frequency point. Using the standard equations of forced motion, a representation of the calibration curve as a function of voltage per unit of ground velocity is calculated. A computer algorithm optimizes the curve and then translates the instrument response into a Seismic Analysis Code (SAC) poles & zeros format. Results have been demonstrated to fall within a few percent of a standard laboratory calibration. This method is an effective and affordable option for networks that employ electro-mechanical seismometers, and it is currently being deployed in

  20. Parameter identification from frequency response of MEMS energy harvesters

    Science.gov (United States)

    Truong, Binh Duc; Le, Cuong Phu; Halvorsen, Einar

    2017-06-01

    In this study, we present theoretical analysis and numerical results on a simple technique for extracting unknown model parameters for MEMS electrostatic energy harvesters. We show that the frequency response can be utilized in a least-squares minimization scheme to estimate the damping coefficient, mechanical stiffness and transducer/load parasitic capacitances. The accuracy of the method is tested by application to simulated cases of linear and non-linear harvesters. A single data sweep from such a pseudo-experiment suffices to determine the unknown parameters of the electromechanical model with accuracy. The method is shown to work satisfactorily for both linear and nonlinear devices.

  1. Estimation of Eastern Denmark’s Electromechanical Modes from Ambient Phasor Measurement Data

    DEFF Research Database (Denmark)

    Vanfretti, Luigi; Garcia-Valle, Rodrigo; Uhlen, Kjetil

    2010-01-01

    In this paper we report on the preliminary results of a collaborative investigation effort between researchers in North America and Europe aiming to baseline the electromechanical modes and mode shapes of the Nordic system from synchronized phasor measurement data. We provide an overview on the D...... at the Radsted and Hovegård substations in Eastern Denmark. The estimated modes are in agreement with those shown in eigenanalysis studies, and other measurement-based investigations. More importantly, the emergence of a new 0.8 Hz mode in Sjælland is reported....

  2. Electromechanical coupling in suspended nanomechanical resonators with a two-dimensional electron gas

    Science.gov (United States)

    Shevyrin, A. A.; Pogosov, A. G.; Bakarov, A. K.; Shklyaev, A. A.

    2017-06-01

    A physical model describing the piezoelectric-effect-mediated influence of bending of a thin suspended cantilever with a two-dimensional electron gas on the conductivity is proposed. The model shows that the conductivity change is almost entirely caused by the rapid change in mechanical stress near the boundary of suspended and non-suspended areas, rather than by the stress itself. An experiment confirming that the electromechanical coupling is associated with the piezoelectric effect is performed. The experimentally measured conductance sensitivity to the cantilever’s vibrations agree with the developed physical model.

  3. Use of Commercial Electrical, Electronic and Electromechanical (EEE) Parts in NASA's Commercial Crew Program (CCP)

    Science.gov (United States)

    Gonzalex, Oscar

    2012-01-01

    NASA's Commercial Crew and Cargo Program (CCP) is stimulating efforts within the private sector to develop and demonstrate safe, reliable, and cost-effective space transportation capabilities. One initiative involves investigating the use of commercial electronic parts. NASA's CCP asked the NASA Engineering and Safety Center (NESC) to collect data to help frame the technical, cost, and schedule risk trades associated with electrical, electronic and electromechanical (EEE) parts selection and specifically expressed desire of some of the CCP partners to employ EEE parts of a lower grade than traditionally used in most NASA safety-critical applications. This document contains the outcome from the NESC's review and analyses.

  4. Influence of micro- and nanofillers on electro-mechanical performance of silicone EAPs

    DEFF Research Database (Denmark)

    Bejenariu, Anca Gabriela; Daugaard, Anders Egede; Skov, Anne Ladegaard

    A well-known technique to improve the tear strength of rubbers is to add micro- or nanofillers. The effects of different micro- and nanofillers on the electro-mechanical behavior of silicone based dielectric elastomer are studied in this work. Several types of fillers and varied loadings are used...... to increase the overall permittivity of the silicone networks. The effect of particle size and particle size distribution on the electrical and viscoelastic properties is investigated. The aim of the paper is to find the right filler and the appropriate concentration for a suitable EAP material...

  5. A Method for Evaluating the Electro-Mechanical Characteristics of Piezoelectric Actuators during Motion

    Directory of Open Access Journals (Sweden)

    Hongzhi Jia

    2012-08-01

    Full Text Available The electro-mechanical characteristics of piezoelectric actuators which have being driven are evaluated in this paper. The force generated by actuators is measured as an inertial force of a corner cub prism which is attached to the actuators. The Doppler frequency shift of a laser beam, due to the motion of actuator, is accurately measured by a heterodyne interferometer. Subsequently, the mechanical quantities, such as velocity, acceleration, force, power and displacement, are calculated from the Doppler frequency shift. With the measurement results of current and voltage of the actuator, the relationships between electrical and mechanical characteristics are evaluated.

  6. Control and measurement of an electro-mechanical system with a phase qubit

    Science.gov (United States)

    Lecocq, Florent; Teufel, John; Allman, Michael; Cicak, Katarina; da Silva, Fabio; Sirois, Adam; Whittaker, Jed; Aumentado, Joe; Simmonds, Ray

    2013-03-01

    We discuss a hybrid device that merges an electro-mechanical system with a metastable phase qubit. The phase qubit can act as a single photon source and detector, allowing the preparation and readout of a lumped element electrical resonator, whose capacitance is formed by a mechanically compliant vacuum-gap capacitor. Via radiation pressure induced parametric coupling, we can map the quantum state of the 10 GHz electrical resonator on to the long-lived, ~10 MHz fundamental mode of the mechanical oscillator. This work opens the way toward the preparation of complex phonon states of mechanical motion. We will discuss current progress with this device.

  7. Poly ionic liquid-based nano composites for smart electro-mechanical devices

    Science.gov (United States)

    Ahmed, Kumkum; Khosla, Ajit; Kawakami, Masaru; Furukawa, Hidemitsu

    2017-04-01

    Conducting polymer composites become increasingly significant for variety of applications in electrical and mechanical devices. Poly (ionic liquid)s (PILs) achieved remarkable interest in this field for the unique properties and added advantages in mechanical stability, improved processability, durability, and spatial controllability. Carbon nanotube (CNT) as filler material to the matrix of PIL can achieve the desired composite material with improved electrical and mechanical properties. In this work, we developed PIL-CNT nanocomposites by using quaternary ammonium type IL monomer and multiwall CNT. Their mechanical, thermal and thermomechanical properties have been studied and future possibilities of employing in electromechanical devices have been explored.

  8. Nondestructive Wireless Monitoring of Early-Age Concrete Strength Gain Using an Innovative Electromechanical Impedance Sensing System

    Directory of Open Access Journals (Sweden)

    C. P. Providakis

    2013-01-01

    Full Text Available Monitoring the concrete early-age strength gain at any arbitrary time from a few minutes to a few hours after mixing is crucial for operations such as removal of frameworks, prestress, or cracking control. This paper presents the development and evaluation of a potential active wireless USB sensing tool that consists of a miniaturized electromechanical impedance measuring chip and a reusable piezoelectric transducer appropriately installed in a Teflon-based enclosure to monitor the concrete strength development at early ages and initial hydration states. In this study, the changes of the measured electromechanical impedance signatures as obtained by using the proposed sensing system during the whole early-age concrete hydration process are experimentally investigated. It is found that the proposed electromechanical impedance (EMI sensing system associated with a properly defined statistical index which evaluates the rate of concrete strength development is very sensitive to the strength gain of concrete structures from their earliest stages.

  9. The Relationships between Atrial Electromechanical Delay and CHA2DS2-VASc Score in Patients Diagnosed with Paroxysmal AF.

    Science.gov (United States)

    Nar, Gökay; İnci, Sinan; Aksan, Gökhan; Soylu, Korhan; Demirelli, Selami; Nar, Rukiye

    2015-09-01

    This study aims to evaluate the relationship between atrial electromechanical delay (AEMD) times and CHA2DS2-VASc scores in patients diagnosed with paroxysmal atrial fibrillation (PAF). The study included a total of 74 patients, 34 of whom were diagnosed with PAF and 40 were included in the control group. The CHA2DS2-VASc score was calculated for each patient. Additionally, blood samples were taken from all patients and transthoracic echocardiographic measurements were made. Left atrial mechanical functions and AEMD were calculated. Mean CHA2DS2-VASc score measured was 2.24 ± 1.53 in PAF group. There was no significant difference between the groups when the patients were evaluated for baseline characteristics and laboratory parameters (P > 0.05) The echocardiographic evaluation of LA mechanical functions showed that only LA minimum volume (19 ± 6.4 vs. 16.7 ± 4.6, P = 0.02) and LA presystolic volume (28.9 ± 7 vs. 25.1 ± 5.7, P = 0.01) were higher in the PAF group. When AEMD was compared between the groups; lateral PA, septal PA, tricuspid PA, Interatrial EMD, and intraatrial EMD were significantly extended compared to control group (P < 0.001) CHA2DS2-VASc score was correlated with Lateral atrial PA (P < 0.001, r = 0.524), Septal atrial PA (P < 0.001, r = 0.45), Interatrial EMD (P < 0.001, r = 0.54), and intraatrial EMD (P < 0.001, r = 0.51) times. The present study shows that AEMD times increase in patients with PAF compared to the control group. Furthermore, this study revealed a correlation between AEMD times and CHA2DS2-VASc score, as well showed that extended AEMD time may be associated with thromboembolism risk. © 2014, Wiley Periodicals, Inc.

  10. Influence of the thermodynamic parameters on the temper embrittlement of SA508 Gr.4N Ni-Cr-Mo low alloy steel with variation of Ni, Cr and Mn contents

    Science.gov (United States)

    Park, Sang-Gyu; Lee, Ki-Hyoung; Min, Ki-Deuk; Kim, Min-Chul; Lee, Bong-Sang

    2012-07-01

    It is well known that SA508 Gr.4N low alloy steel offers improved fracture toughness and strength compared to commercial low alloy steels such as SA508 Gr.3 Mn-Mo-Ni low alloy steel. In this study, the effects of Cr, Mn, and Ni on temper embrittlement in SA508 Gr.4N low alloy steel were evaluated from the viewpoint of thermodynamic parameters such as P diffusivity and C activity. The changes of the ductile-brittle transition temperatures before and after aging were correlated with varying alloying element content, and the diffusivity of P and the activity of C were calculated and correlated with the transition behaviors. The addition of Ni, Cr, and Mn reduce the resistance to temper embrittlement, showing increased Transition-Temperature Shift (TTS) and an increased fraction of intergranular fracture. Although the diffusivity of P is changed by the addition of alloying elements, it does not considerably affect the temper embrittlement. The Mn and Cr content in the matrix significantly reduce the C activity, with showing an inversely proportional relationship to TTS. The change of susceptibility to temper embrittlement caused by Cr and Mn addition could be explained by the variation of C activity. Unlike Cr and Mn, Ni has little effect on the temper embrittlement and C activity.

  11. Influence of the thermodynamic parameters on the temper embrittlement of SA508 Gr.4N Ni-Cr-Mo low alloy steel with variation of Ni, Cr and Mn contents

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang-Gyu; Lee, Ki-Hyoung [Nuclear Materials Research Division, Korea Atomic Energy Research Institute, 150-1 Deogjin-dong, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Min, Ki-Deuk [Division of Material Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Kim, Min-Chul, E-mail: mckim@kaeri.re.kr [Nuclear Materials Research Division, Korea Atomic Energy Research Institute, 150-1 Deogjin-dong, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Lee, Bong-Sang [Nuclear Materials Research Division, Korea Atomic Energy Research Institute, 150-1 Deogjin-dong, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)

    2012-07-15

    It is well known that SA508 Gr.4N low alloy steel offers improved fracture toughness and strength compared to commercial low alloy steels such as SA508 Gr.3 Mn-Mo-Ni low alloy steel. In this study, the effects of Cr, Mn, and Ni on temper embrittlement in SA508 Gr.4N low alloy steel were evaluated from the viewpoint of thermodynamic parameters such as P diffusivity and C activity. The changes of the ductile-brittle transition temperatures before and after aging were correlated with varying alloying element content, and the diffusivity of P and the activity of C were calculated and correlated with the transition behaviors. The addition of Ni, Cr, and Mn reduce the resistance to temper embrittlement, showing increased Transition-Temperature Shift (TTS) and an increased fraction of intergranular fracture. Although the diffusivity of P is changed by the addition of alloying elements, it does not considerably affect the temper embrittlement. The Mn and Cr content in the matrix significantly reduce the C activity, with showing an inversely proportional relationship to TTS. The change of susceptibility to temper embrittlement caused by Cr and Mn addition could be explained by the variation of C activity. Unlike Cr and Mn, Ni has little effect on the temper embrittlement and C activity.

  12. Selection of optimal sintering temperature of K0.5Na0.5NbO3 ceramics for electromechanical applications

    Directory of Open Access Journals (Sweden)

    Gaurav Vats

    2014-03-01

    Full Text Available This paper has considered the selection of the optimal processing parameter (sintering temperature leading to best possible properties of K0.5Na0.5NbO3 (KNN for electromechanical applications. Vital piezoelectric properties for such applications include the piezoelectric coupling coefficient (kp, piezoelectric coefficient (d31, Curie temperature (Tc, remanent polarization (Pr, coercive field (Ec, density (ρ, elastic compliance (S11E and S12E and dielectric loss (tan δ. The weights and priority of these physical properties for KNN are calculated using the modified digital logic (MDL method. The priority order of these properties used for the selection of optimal processing parameters is as d31>tan δ>S11E=S12E>Tc=Pr>ρ>kp>Ec. The weights obtained using MDL are further incorporated with analytic hierarchy process (AHP and VlseKriterijumska Optimisacija I Kompromisno Resenje (VIKOR in order to determine the optimal sintering temperature for KNN. Both methods suggest that 1080 °C and 1120 °C are the most and least desirable sintering temperatures, respectively. Finally, sensitivity analysis is performed for the robustness of our results and prediction of most influential parameter in terms of sensitivity. tan δ is found to be the most sensitive property for alteration in the present ranking.

  13. Ferroelectric KNNT Fibers by Thermoplastic Extrusion Process: Microstructure and Electromechanical Characterization

    Directory of Open Access Journals (Sweden)

    Tony Lusiola

    2015-05-01

    Full Text Available B-site substitution in KNN with tantalum results in a higher d33 and dielectric constant. This higher value makes KNNT interesting for lead-free actuator applications. KNNT fibers with diameters of 300 and 500 μm have been extruded and sintered at 1200 °C in a KNNT-enriched atmosphere. Subsequently, the influence of fiber diameter on the microstructure (porosity and grain size was investigated. The measurements revealed that with decreasing fiber diameter, the porosity increases, whereas the grain size decreases. The influence of these microstructural differences on the piezoelectric properties was evaluated using a novel characterization procedure for single fibers. The larger diameter fibers show an increase in the electromechanical properties measured, i.e., d33, tanδ, Pr, Ec and the free longitudinal fiber displacement, when compared to smaller diameter fibers. The lower alkali losses result in a larger grain size, a higher density during sintering and lead to higher electromechanical properties.

  14. A Study of Concrete Slab Damage Detection Based on the Electromechanical Impedance Method

    Directory of Open Access Journals (Sweden)

    Xianyan Hu

    2014-10-01

    Full Text Available Piezoelectric lead zirconate titanate (PZT is being gradually applied into practice as a new intelligent material for structural health monitoring. In order to study the damage detection properties of PZT on concrete slabs, simply supported reinforced concrete slabs with piezoelectric patches attached to their surfaces were chosen as the research objects and the Electromechanical Impedance method (EMI was adopted for research. Five kinds of damage condition were designed to test the impedance values at different frequency bands. Consistent rules are found by calculation and analysis. Both the root mean square deviation (RMSD and the correlation coefficient deviation (CCD damage indices are capable of detecting the structural damage. The newly proposed damage index Ry/Rx can also predict the changes well. The numerical and experimental studies verify that the Electromechanical Impedance method can accurately predict changes in the amount of damage in reinforced concrete slabs. The damage index changes regularly with the distance of damages to the sensor. This relationship can be used to determine the damage location. The newly proposed damage index Ry/Rx is accurate in determining the damage location.

  15. Operation of a high quality-factor gyroscope in electromechanical nonlinearities regime

    Science.gov (United States)

    Taheri-Tehrani, P.; Defoort, M.; Horsley, D. A.

    2017-07-01

    This paper describes the operation of a high quality factor gyroscope in various regimes where electromechanical nonlinearities introduce different forms of amplitude-frequency (A-f) dependence. Experiments are conducted using an epitaxially-encapsulated 2  ×  2 mm2 quad-mass gyroscope (QMG) with a quality factor of 85 000. The device exhibits third-order Duffing nonlinearity at low bias voltages (15 V) due to the mechanical nonlinearity in the flexures and at high bias voltages (35 V) due to third-order electrostatic nonlinearity. At intermediate voltages (~26 V), these third-order nonlinearities cancel and the amplitude-frequency dependence is greatly reduced. A model is developed to demonstrate the connection between the electromechanical nonlinearities and the amplitude-frequency dependence, also known as the backbone curve. Gyroscope operation is demonstrated in each nonlinear operating regime and the key performance measures of the gyroscope’s performance, angle random walk (ARW) and bias instability, are measured as a function of drive-mode vibration amplitude. We find that low ARW can be achieved even though the gyroscope’s drive mode exhibits large amplitude-frequency dependence, and that bias instability is largely independent of the operating regime.

  16. Electromechanical modeling and experimental analysis of a compression-based piezoelectric vibration energy harvester

    Directory of Open Access Journals (Sweden)

    X.Z. Jiang

    2014-07-01

    Full Text Available Over the past few decades, wireless sensor networks have been widely used in the field of structure health monitoring of civil, mechanical, and aerospace systems. Currently, most wireless sensor networks are battery-powered and it is costly and unsustainable for maintenance because of the requirement for frequent battery replacements. As an attempt to address such issue, this article theoretically and experimentally studies a compression-based piezoelectric energy harvester using a multilayer stack configuration, which is suitable for civil infrastructure system applications where large compressive loads occur, such as heavily vehicular loading acting on pavements. In this article, we firstly present analytical and numerical modeling of the piezoelectric multilayer stack under axial compressive loading, which is based on the linear theory of piezoelectricity. A two-degree-of-freedom electromechanical model, considering both the mechanical and electrical aspects of the proposed harvester, was developed to characterize the harvested electrical power under the external electrical load. Exact closed-form expressions of the electromechanical models have been derived to analyze the mechanical and electrical properties of the proposed harvester. The theoretical analyses are validated through several experiments for a test prototype under harmonic excitations. The test results exhibit very good agreement with the analytical analyses and numerical simulations for a range of resistive loads and input excitation levels.

  17. Strongly-coupled 2D membrane resonators in superconducting electromechanical circuits

    Science.gov (United States)

    Northeast, David; Knobel, Robert

    Nanomechanical devices have allowed for the study of the motion of macroscopic objects near their quantum ground state for mechanical motion. Coupling these devices to resonant electrical circuits provides a method of measuring with standard laboratory electronics, and a means to interact and cool towards the ground state. We report on current work, in microwave LC resonators, toward the use of graphene and niobium diselenide (NbSe2) membranes as one electrode in a parallel plate capacitor with a mechanical degree of freedom. The membrane's light mass, non-linear response to an applied force and tunability potentially enable stronger electromechanical amplification and coupling. Previous work using graphene in similar systems shows that graphene's electrical resistance is a limiting factor when attempting to cool via electromechanical sideband interactions. In contrast, NbSe2 is a superconductor even in single layer form, and this property has the potential to provide a system with lower loss while driving with increasing photon number, as compared to the graphene-based systems. In this talk we show fabrication, modelling and progress towards quantum-limited measurements. We acknowledge support for this work from NSERC and CMC Microsystems.

  18. Electromechanical control of nitrogen-vacancy defect emission using graphene NEMS

    Science.gov (United States)

    Reserbat-Plantey, Antoine; Schädler, Kevin G.; Gaudreau, Louis; Navickaite, Gabriele; Güttinger, Johannes; Chang, Darrick; Toninelli, Costanza; Bachtold, Adrian; Koppens, Frank H. L.

    2016-01-01

    Despite recent progress in nano-optomechanics, active control of optical fields at the nanoscale has not been achieved with an on-chip nano-electromechanical system (NEMS) thus far. Here we present a new type of hybrid system, consisting of an on-chip graphene NEMS suspended a few tens of nanometres above nitrogen-vacancy centres (NVCs), which are stable single-photon emitters embedded in nanodiamonds. Electromechanical control of the photons emitted by the NVC is provided by electrostatic tuning of the graphene NEMS position, which is transduced to a modulation of NVC emission intensity. The optomechanical coupling between the graphene displacement and the NVC emission is based on near-field dipole-dipole interaction. This class of optomechanical coupling increases strongly for smaller distances, making it suitable for nanoscale devices. These achievements hold promise for selective control of emitter arrays on-chip, optical spectroscopy of individual nano-objects, integrated optomechanical information processing and open new avenues towards quantum optomechanics.

  19. Unified model for the electromechanical coupling factor of orthorhombic piezoelectric rectangular bar with arbitrary aspect ratio

    Science.gov (United States)

    Rouffaud, R.; Levassort, F.; Hladky-Hennion, A.-C.

    2017-02-01

    Piezoelectric Single Crystals (PSC) are increasingly used in the manufacture of ultrasonic transducers and in particular for linear arrays or single element transducers. Among these PSCs, according to their microstructure and poled direction, some exhibit a mm2 symmetry. The analytical expression of the electromechanical coupling coefficient for a vibration mode along the poling direction for piezoelectric rectangular bar resonator is established. It is based on the mode coupling theory and fundamental energy ratio definition of electromechanical coupling coefficients. This unified formula for mm2 symmetry class material is obtained as a function of an aspect ratio (G) where the two extreme cases correspond to a thin plate (with a vibration mode characterized by the thickness coupling factor, kt) and a thin bar (characterized by k33'). To optimize the k33' value related to the thin bar design, a rotation of the crystallogaphic axis in the plane orthogonal to the poling direction is done to choose the highest value for PIN-PMN-PT single crystal. Finally, finite element calculations are performed to deduce resonance frequencies and coupling coefficients in a large range of G value to confirm developed analytical relations.

  20. Modification and Performance Evaluation of a Low Cost Electro-Mechanically Operated Creep Testing Machine

    Directory of Open Access Journals (Sweden)

    John J. MOMOH

    2010-12-01

    Full Text Available Existing mechanically operated tensile and creep testing machine was modified to a low cost, electro-mechanically operated creep testing machine capable of determining the creep properties of aluminum, lead and thermoplastic materials as a function of applied stress, time and temperature. The modification of the testing machine was necessitated by having an electro-mechanically operated creep testing machine as a demonstration model ideal for use and laboratory demonstrations, which will provide an economical means of performing standard creep experiments. The experimental result is a more comprehensive understanding of the laboratory experience, as the technology behind the creep testing machine, the test methodology and the response of materials loaded during experiment are explored. The machine provides a low cost solution for Mechanics of Materials laboratories interested in creep testing experiment and demonstration but not capable of funding the acquisition of commercially available creep testing machines. Creep curves of strain versus time on a thermoplastic material were plotted at a stress level of 1.95MPa, 3.25MPa and 4.55MPa and temperature of 20oC, 40oC and 60oC respectively. The machine is satisfactory since it is always ready for operation at any given time.