Dynamic Deviation Research Articles

Dynamic Behaviors of Mucky Clay Material under Cyclic Loads

A series of consolidated-undrained (CU) triaxial compression tests and dynamic triaxial tests on mucky clay material were performed in the present paper, and the dynamic behaviors of mucky clay material for different dynamic stress amplitudes and initial static deviator stresses were studied. It is indicated that both the accumulated strain and the pore water pressure increase rapidly with increasing number of cycles. While after a certain number of cycles, the accumulated strain tends to be stable and there is enough time for the equilibrium of pore water pressure. Results also show that the influences of dynamic stress amplitudes and initial static deviator stresses on the accumulated plastic strain and pore water pressure of the mucky clay material are significant.

Influences of Subgrade Structure Form on Dynamic Responses of Railway Subgrade under Cyclic Loading

This paper presents conducted field tests of cyclic loading for railway subgrade. These tests studied the influences of subgrade structure forms of embankment and cutting on the dynamic responses of railway subgrade. The considered dynamic responses included the distribution of dynamic stress in railway subgrade, and the elastic deformation, dynamic stiffness, and cumulative plastic deformation on subgrade surface. The number of cyclic loading in testing was separately about two millions for an embankment and a cutting. The dynamic deviator stress applied on subgrade surface was 92kPa to simulate the maximum stress induced by moving train for the designed railway. Gathered data showed that the dynamic stiffness on subgrade surface for a cutting was approximately a half of the one for an embankment. However, the cumulative plastic deformation was essentially the same for the two forms of subgrade (i.e. the embankment and the cutting). These results provide references for the design of railway subgrade.

Gaussian global-best harmony search algorithm for optimization problems

In this paper, a novel optimization approach is proposed using Gaussian distribution function to improve harmony search (HS) algorithm, namely “Gaussian global-best harmony search” (GGHS) algorithm. The harmony memory (HM) is adjusted using Gaussian random generation in GGHS. The GGHS algorithm consists of two adjustment steps; in the first stage, the harmony memory is adjusted by a dynamic bandwidth and the Gaussian distribution with a mean of 0 and a standard deviation of 1. In the second stage, the best memory is adjusted using a random Gaussian number with a mean of 0 and a dynamic standard deviation. The dynamic bandwidth and standard deviation are adaptively determined based on iteration number, the maximum and minimum of each design variable in the HM. Accuracy and efficiency of the GGHS algorithm have been evaluated using several benchmark mathematical examples. The numerical results illustrate that the GGHS algorithm is more accurate and efficient than other existing modified versions of harmony search algorithm. The capability of the dynamic bandwidth enhances the performance of this modified HS algorithm. The GGHS produces the better optimum results in comparison with other improved versions of harmony search algorithm.

Density, viscosity, refraction index and excess properties of binary mixtures of 1-(1-methypiperidinium-1-yl) pentane-(1-pyridinium) bis(trifluoromethane) sulfonamide with acetonitrile at T=(293.15 to 323.15) K

The density, viscosity, and refractive index of a pure asymmetrical dicationic ionic liquid, 1-(1-methypiperidinium-1-yl) pentane-(1-pyridinium) bis(trifluoromethane)sulfonamide, and its binary mixtures with acetonitrile were investigated at temperatures from 293.15 K to 323.15 K over the entire range of composition at ambient pressure. From the experimental data, the excess molar volumes, dynamic viscosity deviations, and refractive index deviations were, respectively,calculated and correlated with Redlich-Kister-type polynomials. The temperature dependence of viscosity for pure ionic liquid was described by modified Vogel–Tammann-Fulcher (VTF) equation. The enthalpy and entropy of activation for viscous flow were obtained. The values of molar refraction and polarizability indicated that the dominant interactions between ionic liquids and acetonitrile were dipole-dipole molecular interactions. These thermodynamic properties were discussed in terms of nature of molecular interactions between the ionic liquid and acetonitrile.

Iterative learning for machine tools using a convex optimisation approach

Abstract Dynamic, quasi-static and motion control deviations lead to nonlinear but systematic tracking errors. It is shown that these errors can be reduced significantly by adjusting the set points using an optimization based iterative learning approach. This method uses either values obtained from internal encoders or alternatively tool center point measurements. The approach is presented, discussed and validated using simulation and measurement results.

A Dynamic Coherency Identification Method Based on Frequency Deviation Signals

This paper presents a new method to dynamically determine coherent generators and electrical areas of an interconnected power system. The proposed method is based on dynamic frequency deviations of both generator and non-generator buses, with respect to the system nominal frequency. The proposed method 1) largely overcomes the limitations of the existing model-based and measurement-based coherency identification methods, 2) enables dynamic tracking of the coherency time-evolution, and 3) provides noise immunity which is imperative in practical implementation. The method also promises the potential for real-time coherency calculation. The proposed method is applied to the 16-machine/68-bus NPCC system based on time-domain simulation studies in the PSS/E platform and the results are compared with those of the classical slow-coherency (model-based) method and a measurement-based method.

Joint-digital-predistortion for wireless transmitter’s I/Q imbalance and PA nonlinearities using an asymmetrical complexity-reduced Volterra series model

I/Q imbalance and nonlinearities of power amplifier (PA) are the main impairments of wireless transmitters degrading the spectral purity and error vector magnitude (EVM). In order to jointly migrate them, an asymmetrical complexity-reduced Volterra series model is proposed, namely joint-digital predistortion (joint-DPD). Our joint-DPD is inspired by the interaction between such two impairments, providing high degree of dynamic nonlinearities with large memory depths. Also, by understanding the structure of joint-DPD for OFDM signals, lower computational complexity can be achieved by pruning the redundant terms with an asymmetrical structure. The corresponding analysis offers the theoretical basis and its related complexity over different Volterra-series-based joint-DPDs. The performances are evaluated under two scenarios. Especially when a 3.4-dB back-off input power is applied, where severe PA nonlinearities are presented with the I/Q imbalance, the measured (left, right) adjacent channel power ratio is improved from (?19.9, ?19.6 dBc) to (?37.3, ?37.9 dBc), and the EVM is reduced from 22.1 to 3.4 %. For performance comparison, other Volterra-series-based DPDs such as memory polynomial, dynamic deviation reduction and generalized memory polynomial, are also extended to joint-DPD.

A Modified Canonical Piecewise-Linear Function-Based Behavioral Model for Wideband Power Amplifiers

A band-limited canonical piecewise-linear function (CPWL)-based model is proposed for wideband power amplifiers (PAs). The model has a similar structure of the band-limited dynamic deviation reduction (DDR) Volterra series model but without high-order terms and long finite impulse response filters, which are replaced by CPWL. The model has lower complexity and more flexibility than the band-limited DDR Volterra series model and the model parameters can be estimated by the least-square method. Experimental results show that the proposed model nearly gives the same normalized mean square error and digital predistortion performance as the band-limited Volterra series when a wideband PA is excited by a 5-carrier long-term evolution advanced signal of 100-MHz bandwidth.

ModelPlex: verified runtime validation of verified cyber-physical system models

Formal verification and validation play a crucial role in making cyber-physical systems (CPS) safe. Formal methods make strong guarantees about the system behavior if accurate models of the system can be obtained, including models of the controller and of the physical dynamics. In CPS, models are essential; but any model we could possibly build necessarily deviates from the real world. If the real system fits to the model, its behavior is guaranteed to satisfy the correctness properties verified with respect to the model. Otherwise, all bets are off. This article introduces ModelPlex, a method ensuring that verification results about models apply to CPS implementations. ModelPlex provides correctness guarantees for CPS executions at runtime: it combines offline verification of CPS models with runtime validation of system executions for compliance with the model. ModelPlex ensures in a provably correct way that the verification results obtained for the model apply to the actual system runs by monitoring the behavior of the world for compliance with the model. If, at some point, the observed behavior no longer complies with the model so that offline verification results no longer apply, ModelPlex initiates provably safe fallback actions, assuming the system dynamics deviation is bounded. This article, furthermore, develops a systematic technique to synthesize provably correct monitors automatically from CPS proofs in differential dynamic logic by a correct-by-construction approach, leading to verifiably correct runtime model validation. Overall, ModelPlex generates provably correct monitor conditions that, if checked to hold at runtime, are provably guaranteed to imply that the offline safety verification results about the CPS model apply to the present run of the actual CPS implementation.

Screwdown load deviation model of 5 m heavy plate mill based on influence of back-up roll axial force

Screwdown load deviation threatens rolling mill safety and product quality. The contact between a 5 m rolling mill screwdown device and the back-up roll (BUR) bearing chock was simplified to a fixed hinge constraint, and the constraint of the keeper plates on the BUR bearing chock was simplified to a sliding hinge constraint. According to the BUR space force and moment equilibrium, a screwdown load deviation model affected by the BUR axial force was used to simulate the effect of the roll crossing degree on the screwdown load deviation. Screwdown load deviations were calculated for three rolling passes. The results are more consistent with the data than outputs calculated by a model that neglects axial force. Assumptions about the relationship between the load deviation and the work roll axial forces agree with the data. The results show that the BUR axial force causes a dynamic deviation of the screwdown load.

Quantum adiabatic evolution with energy degeneracy levels

A classical-kind phase-space formalism is developed to address the tiny intrinsic dynamical deviation from what is predicted by Wilczek-Zee theorem during quantum adiabatic evolution on degeneracy levels. In this formalism, the Hilbert space and the aggregate of degenerate eigenstates become the classical-kind phase-space and a high-dimensional subspace in the phase-space, respectively. Compared with the previous same study by a different method, the current result is qualitatively different in that the first-order deviation derived here is always perpendicular to the degeneracy subspace. A tripod scheme Hamiltonian with two degenerate dark states is employed to illustrate the adiabatic deviation with degeneracy levels.

Iterative Learning for Machine Tools Using a Convex Optimisation Approach

Dynamic, quasi-static and motion control deviations lead to nonlinear but systematic tracking errors. It is shown that these errors can be reduced significantly by adjusting the set points using an optimization based iterative learning approach. This method uses either values obtained from internal encoders or alternatively tool center point measurements. The approach is presented, discussed and validated using simulation and measurement results.

A Three-Port Nonlinear Dynamic Behavioral Model for Supply-Modulated RF PAs

We propose a three-port nonlinear dynamic behavioral model for supply-modulated power amplifiers (PAs). The proposed model not only accounts for the radio frequency (RF) input-output relationship, but also for the interaction between a modulated voltage supply, the RF output power and the supply current. The model is based on a modified Volterra formulation which accounts for the dynamic deviations with respect to a quasi-static model. The frequency-domain kernels of the proposed model are directly extracted from measurements performed with a low-frequency-extended large-signal network analyzer on an RF hand-set PA. The model is validated under random multitone modulated RF input and supply. The presented technique allows for the independent control of the RF and the supply ports. As such, it allows a separate description of both the dynamic contribution of the RF modulated input and of the dynamic supply voltage. The proposed model shows an improvement with respect to a quasi-static approach in predicting the RF output, the supply current, as well as the power-added efficiency.

Spinning, mechanical and thermal properties of metallocene polypropylene fibers

The higher mechanical properties of polypropylene (PP) fibers based on metallocene-catalyzed PP (miPP) in comparison with fibers based on Ziegler–Natta-catalyzed PP (zniPP) were presented in periodic literature in the last decade. At the same time the miPP fibers have lower crystallinity and lower melting temperature compared with conventional zniPP fibers. In our experimental work, the thermal and mechanical properties of both the miPP and zniPP multifilaments depending on their spinning and drawing conditions were investigated. The dynamic viscosity and deviation from the Newtonian flow of polymer melt were evaluated as important parameters for melt-spinning technology. The melting temperature, melting enthalpy and melting entropy of multifilaments were investigated using DSC analysis in dependence on spinning temperature and draw ratio of fibers. At the same time the mechanical properties of fibers tenacity, elongation and elastic modulus were measured. The DSC measurements were carried out using conventional method and constant length method at which the constant length of fibers was held (constrained fibers). The changes in melting temperature, melting enthalpy and melting entropy of drawn fibers were analyzed and correlated with mechanical properties of fibers. The mechanical and thermal properties of fibers were discussed with regard to the spinning and drawing conditions as well.

Multi-sensor calibration of low-cost magnetic, angular rate and gravity systems.

We present a new calibration procedure for low-cost nine degrees-of-freedom (9DOF) magnetic, angular rate and gravity (MARG) sensor systems, which relies on a calibration cube, a reference table and a body sensor network (BSN). The 9DOF MARG sensor is part of our recently-developed “Integrated Posture and Activity Network by Medit Aachen” (IPANEMA) BSN. The advantage of this new approach is the use of the calibration cube, which allows for easy integration of two sensor nodes of the IPANEMA BSN. One 9DOF MARG sensor node is thereby used for calibration; the second 9DOF MARG sensor node is used for reference measurements. A novel algorithm uses these measurements to further improve the performance of the calibration procedure by processing arbitrarily-executed motions. In addition, the calibration routine can be used in an alignment procedure to minimize errors in the orientation between the 9DOF MARG sensor system and a motion capture inertial reference system. A two-stage experimental study is conducted to underline the performance of our calibration procedure. In both stages of the proposed calibration procedure, the BSN data, as well as reference tracking data are recorded. In the first stage, the mean values of all sensor outputs are determined as the absolute measurement offset to minimize integration errors in the derived movement model of the corresponding body segment. The second stage deals with the dynamic characteristics of the measurement system where the dynamic deviation of the sensor output compared to a reference system is corrected. In practical validation experiments, this procedure showed promising results with a maximum RMS error of .

Assessing Short-Term Voltage Stability of Electric Power Systems by a Hierarchical Intelligent System

In the smart grid paradigm, growing integration of large-scale intermittent renewable energies has introduced significant uncertainties to the operations of an electric power system. This makes real-time dynamic security assessment (DSA) a necessity to enable enhanced situational-awareness against the risk of blackouts. Conventional DSA methods are mainly based on the time-domain simulation, which are insufficiently fast and knowledge-poor. In recent years, the intelligent system (IS) strategy has been identified as a promising approach to facilitate real-time DSA. While previous works mainly concentrate on the rotor angle stability, this paper focuses on another yet increasingly important dynamic insecurity phenomenon-the short-term voltage instability, which involves fast and complex load dynamics. The problem is modeled as a classification subproblem for transient voltage collapse and a prediction subproblem for unacceptable dynamic voltage deviation. A hierarchical IS is developed to address the two subproblems sequentially. The IS is based on ensemble learning of random-weights neural networks and is implemented in an offline training, a real-time application, and an online updating pattern. The simulation results on the New England 39-bus system verify its superiority in both learning speed and accuracy over some state-of-the-art learning algorithms.

Investigation of distillation systems using heavy or intermediate entrainers for separating toluene–methanol: process economics and control

ABSTRACTBACKGROUNDThe separation of methanol–toluene by introducing aniline or triethylamine (Et3N) is investigated, with aniline and Et3N as heavy and intermediate entrainers, respectively. First, the conventional extractive distillation process with aniline as the extractive entrainer (HE) and the direct/indirect separating sequences using Et3N as intermediate entrainer (IE‐D/IE‐I) have been designed and optimized with rigorous simulations. Subsequently, the dynamic performances of these optimized processes are investigated with simple temperature control strategies. Finally, the steady‐state process economics and dynamic performances for these processes are facilitated.RESULTSThe IE‐I process has a 7.26% total annual cost (TAC) saving compared with the HE process and the total energy cost of the IE‐I process is 18.79% lower than that of the HE process. As to dynamic performances, the maximum transient deviation of the methanol product purity in the IE‐I process is much smaller than that in the HE process when ±20% feed flow rate disturbances are introduced. And when −20% step toluene composition disturbance is introduced, the new steady‐state methanol product purity in the HE process is 99.5 mol% while that in the IE‐I process is 99.8%.CONCLUSIONSThe numerical and graphic comparisons indicate that the IE‐I process possesses advantages over the HE process to some extent. The small advantages possessed by the IE‐I process are mainly those of the use of lower‐grade heat source, lower energy consumption and smaller dynamic deviations under feed disturbances. © 2015 Society of Chemical Industry

Excess properties and spectroscopic studies of binary system 1,4-butanediol + water at T = (293.15, 298.15, 303.15, 308.15, 313.15 and 318.15) K

ABSTRACTDensity and dynamic viscosity data were measured over the whole concentration range for the binary system 1,4-butanediol (1) + water (2) at T = (293.15, 298.15, 303.15, 308.15, 313.15, and 318.15) K as a function of composition under atmospheric pressure. Based on density and dynamic viscosity data, excess molar density (ρE), dynamic viscosity deviation (Δν) and excess molar volume (VmE) were calculated. From the dynamic viscosity data, excess Gibbs energies (ΔG*E), Gibbs free energy of activation of viscous flow (ΔG*), enthalpy of activation for viscous flow (ΔH*) and entropy of activation for viscous flow (ΔS*) were also calculated. The ρE, VmE, Δν and ΔG*E values were correlated by a Redlich−Kister-type function to obtain the coefficients and to estimate the standard deviations between the experimental and calculated quantities. Based on FTIR and UV spectral results, the intermolecular interaction of 1,4-butanediol with H2O was discussed.

Density, viscosity and spectroscopic studies of the binary system 1,2-ethylenediamine + 1,4-butanediol at T = (293.15 to 318.15) K

Densities and viscosities were measured under atmospheric pressure over the entire concentration range for the binary system 1,2-ethanediamine (EDA)+1,4-butanediol (BDO) at T=293.15, 298.15, 303.15, 308.15, 313.15, and 318.15K as a function of composition. Based on density and viscosity data, excess molar volumes (VmE) and dynamic viscosity deviations (∆ν) were calculated. VmE and ∆ν values were correlated by a Redlich–Kister type function to obtain the coefficients and to estimate the standard deviation between the experimental and calculated quantities. Based on FTIR and UV–vis spectral results, the intermolecular interaction between EDA and BDO was discussed.

The role of botulinum toxin a in the establishment of symmetry in pediatric paralysis of the lower lip.

Botulinum toxin A has been described as an effective adjunct treatment for achieving symmetry in adults with facial paralysis. Few investigators have described the use of botulinum toxin A in pediatric patients with facial paralysis. To present our preliminary experience with botulinum toxin A in pediatric patients presenting with asymmetry of the lower lip. We performed a retrospective medical record review of all pediatric patients (age range, 4-17 years; mean [SD] age, 11.2 [4.7] years) with facial paralysis who were treated with botulinum toxin A injections from January 1, 2004, through December 31, 2012. Patients presented for treatment at The Hospital for Sick Children, Toronto, Ontario, Canada, or the Massachusetts Eye and Ear Infirmary, Boston. Using facial analysis software, we measured lower lip asymmetry in the patients' photographs before and after treatment, at rest, and in a dynamic state. We performed analysis of variance to assess for improvement in symmetry. We identified 18 patients with the following 3 primary indications for treatment: focal lip asymmetry (n = 11), extensive hemifacial asymmetry (n = 5), and focal synkinesis (n = 2). We found no complications related to botulinum toxin A treatment. The mean (SD) dynamic deviation before the injection was 3.5 (1.7) mm, whereas the mean dynamic deviation after the injection was 1.5 (0.8) mm. The mean (SD) deviation correction was evaluated at 61% (6%) and was statistically significant (P = .04). Botulinum toxin A injection is a safe procedure for improving localized asymmetry in pediatric patients with facial paralysis. Preliminary results indicate that botulinum toxin A may be an effective treatment for lower lip asymmetry in children and adolescents. 4.