Characterization of spherically focused transducers using an ultrasonic measurement model approach

A new and computationally efficient method is developed for characterizing a spherically focused, ultrasonic transducer (and its accompanying test system). Procedures for determining the probe's effective radius, effective focal length, and system efficiency factor are described. Predicted responses that make use of these effective parameters are shown to correspond very well to measured responses for a number of different transducers.     

Increasing the accuracy of design methods using inhomogeneous experimental data

A method is proposed for utilizing inhomogeneous experimental data. It can be applied in order to increase the accuracy of methods for estimating the probability indicators for the properties of devices when planning their manufacture by making use of inhomogenous experimental data obtained at the end of the life cycle of such devices. Translated from Izmeritel'naya Tekhnika, No. 2, pp. 16–19, February, 1998.     

Analysis and design of focused interdigital transducers

Focused interdigital transducers (FIDTs) can generate surface acoustic wave (SAW) with high intensity and high beamwidth compression ratio. Owing to these features, they are very suitable to be used as the sources of microacoustic channels or waveguides in the near future. The focusing properties of FIDTs are dominated solely by their geometric shapes. Therefore, to obtain optimal performance, it is essential to analyze the FIDTs with a variety of geometric shapes. However, among the existing studies concerning the diffraction of FIDTs, a detailed analysis and design of FIDTs is still in paucity. In this paper, we adopted the exact angular spectrum of plane wave theory (ASoW) to calculate the amplitude fields of FIDTs on Y-Z lithium niobate (LiNbO3) with the shape as a concentric circular arc and the concentric wave surface. Based on the calculation results, we discussed the variations of the amplitude fields induced by changing number of pairs, degree of arc, and geometric focal length. In addition, the focusing properties of FIDTs on the (100)-oriented GaAs substrate were also analyzed and discussed. We also summarized the guiderules for designing a FIDT via four important factors. It is worth noting that the results of this study provide an important basis for designing various FIDTs to fit the desired applications.     

Synchronous generator third-order model parameter estimation using online experimental data

A method to estimate the dynamic parameters of the commonly used third-order d-q model of a synchronous generator, based on measured electrical power, reactive power, terminal voltage, field current, field voltage and rotor angle following a small perturbation of the field voltage, is described. The parameters are estimated from two newly developed nonlinear functions for electrical power and terminal voltage by using a nonlinear least squares (NLS) algorithm. Results of simulation studies and experimental data collected from an 80 MVA, 10.5 kV generator show the efficacy of the proposed method and also reveal that the proposed method is valid for a wide range of operating conditions. For cases where rotor angle is not available, a new method for rotor angle estimation is also proposed.     

Analysis of data obtained from a frequency-multiplexed phase-modulation fluorometer using an autoregressive model

In order to derive plural values of fluorescence lifetimes simultaneously from a multi-component sample, we formulate a mathematical method for analyzing data obtained from a frequency-multiplexed phase-modulation fluorometer (FM-PMF) using an autoregressive (AR) model. Various parameter settings necessary for performing accurate data analysis based on the AR model are studied through numerical simulations. Measurement results of fluorescence lifetimes of real samples, 10 ppm quinine sulfate in 0.1 N H(2)SO(4), 10 ppm rhodamine 6G in ethanol, and their mixture with a volume ratio of 1:1, demonstrate that the proposed method works quite well.     

Air pollution prediction by using an artificial neural network model

Clean Technologies and Environmental Policy - Air pollutants impact public health, socioeconomics, politics, agriculture, and the environment. The objective of this study was to evaluate the...     

Analysis of predicted residual stress in a weld and comparison with experimental data using regression model

Residual stress in a welded plate is computed in the first part of the paper using a weld analysis software program VrWeld () that computes the 3D transient temperature field, the evolution of micro-structure and the evolution of stress-strain fields. The computed residual stress is compared to the residual stress distribution measured by Paradowska (J Mater Process 164–165:1099–1105, 2005) with a neutron diffraction method to show that the computational model captures the physics well. Two uncertainty analyses are conducted in the second part to investigate the question of how variations in parameters contribute to the result from part one provided that computational model can predict residual stress well resulted in part one. The difference between the two is the number of parameters. The former has only one parameter and we employed the computational model for perturbation analysis in order to find the uncertainty due to perturbation in the parameter. For such a test, the number of test required in sample space to approximate normality by central limit theorem, is feasible considering computational resources although it is not true when we have higher number of interrelated parameters. The latter therefore has 4 highly interrelated parameters to show that an alternative way can be employed instead of using directly computational model for such a case. Uncertainty analyses are based on Monte Carlo method in this paper and the idea is that if numerical modeling is valid and also there is a need for a great number of tests for Monte Carlo analysis that make it unfeasible to run such an analysis directly by computational model then extracting a regression model from the computational model and working with it, is an effective alternative.     

Biomechanical analyses of whiplash injuries using an experimental model

Neck pain and headaches are the two most common symptoms of whiplash. The working hypothesis is that pain originates from excessive motions in the upper and lower cervical segments. The research design used an intact human cadaver head-neck complex as an experimental model. The intact head-neck preparation was fixed at the thoracic end with the head unconstrained. Retroreflective targets were placed on the mastoid process, anterior regions of the vertebral bodies, and lateral masses at every spinal level. Whiplash loading was delivered using a mini-sled pendulum device. A six-axis load cell and an accelerometer were attached to the inferior fixation of the specimen. High-speed video cameras were used to obtain the kinematics. During the initial stages of loading, a transient decoupling of the head occurs with respect to the neck exhibiting a lag of the cranium. The upper cervical spine-head undergoes local flexion concomitant with a lag of the head while the lower column is in local extension. This establishes a reverse curvature to the head-neck complex. With continuing application of whiplash loading, the inertia of the head catches up with the neck. Later, the entire head-neck complex is under an extension mode with a single extension curvature. The lower cervical facet joint kinematics demonstrates varying local compression and sliding. While the anterior- and posterior-most regions of the facet joint slide, the posterior-most region of the joint compresses more than the anterior-most region. These varying kinematics at the two ends of the facet joint result in a pinching mechanism. Excessive flexion of the posterior upper cervical regions can be correlated to headaches. The pinching mechanism of the facet joints can be correlated to neck pain. The kinematics of the soft tissue-related structures explain the mechanism of these common whiplash associated disorders.     

Memory core design and drive pulse optimization using a charge model of the storage core and its computer implementation

The representation of the switching characteristics of the ferrite memory core by flux-charge curves and the derivation of significant design or application parameters for a new, undeveloped ferrite memory core are described. The technique used is that of appropriately scaling flux and charge by a computer program. User options permit computation of signal and noise amplitudes and waveforms, read current and percent flux switched, core height and threshold, or outer and inner diameters, depending on the information available as input data. Effects of parameter tolerances can be evaluated, and technology advances effecting device improvement can be indicated and accommodated.     

An initial data model,using the object-oriented paradigm,for sculptured-feature-based design

This paper presents an initial object [1] model based on entity/relationship [2] structures for sculptured-feature-based design. The model provides the basis for a system that will allow designers to define their products in terms of interacting features they recognise, and categories that are meaningful to their organisation. Design solutions can also be explored and ultimately defined by means of parametric shape algorithms and values relevant to a particular product domain. Finally, the three-dimensional geometry can be evaluated throughout the design activity for visualisation, analysis, and ultimately manufacture.     

绿色包装设计模式的解析

论述了绿色包装设计对于人与自然的生态平衡关系,以及如何提高其产品在国内外的市场竞争力.促使人们重新面对一个基本问题:市场需求什么样的产品包装,如何设计这些产品包装.基于可持续发展的战略思想,提出了探索新的包装设计模式,传达绿色资讯,引导绿色消费.     

Optimal experimental design in an epidermal growth factor receptor signalling and down-regulation model

We apply the methods of optimal experimental design to a differential equation model for epidermal growth factor receptor signalling, trafficking and down-regulation. The model incorporates the role of a recently discovered protein complex made up of the E3 ubiquitin ligase, Cbl, the guanine exchange factor (GEF), Cool-1 (beta -Pix) and the Rho family G protein Cdc42. The complex has been suggested to be important in disrupting receptor down-regulation. We demonstrate that the model interactions can accurately reproduce the experimental observations, that they can be used to make predictions with accompanying uncertainties, and that we can apply ideas of optimal experimental design to suggest new experiments that reduce the uncertainty on unmeasurable components of the system.     

Analysis of experimental design with multivariate response: A contribution using multiblock techniques

In many application areas, experimental approaches both involve an experimental design that determines changes in the studying factors and an untargeted analytical method (IR, LC-MS, NMR,…) used to characterize the samples by a large number of variables. This leads to a resulting data set which can be structured in blocks with respect to the different levels of the experimental factors. Among the methods that have been developed to address this situation, the ANOVA-Simultaneous Component Analysis (ASCA) is the only one which proposes the use of a multiblock technique to date. Nevertheless, other possibilities are achievable. Therefore in this article, we propose 1) to adopt another way of defining and organizing the blocks from the initial matrix and 2) to apply Multiple Co-inertia Analysis (MCoA) a multiblock method different from Simultaneous Component Analysis to manage this new scenario. The complementarities of our proposal with ASCA are demonstrated on a case study related to cheese processing.     

Analysis of experimental data on low-cycle fatigue in nonproportional deformation

We have analyzed experimental data on low-cycle fatigue in biaxial nonproportional deformation of various materials. To establish a correlation with the fatigue limit, we have proposed a strain parameter-the reduced range of strain. For most of the materials under consideration this correlation dependence can be obtained from uniaxial low-cycle fatigue experiments and can be represented by a linear function. Institute of Problems of Strength, National Academy of Sciences of Ukraine, Kiev, Ukraine. Translated from Problemy Prochnosti, No. 1, pp. 13–21, January–February, 2000.     

On the confidence limit of the systematic error of an LSM model that approximates experimental data

A method is proposed for evaluation of the confidence limit of a least-squares-method model for approximation of experimental data. Translated from Izmeritel'naya Tekhnika, No. 7, pp. 8–11, July, 2000.     

An artificial neural network model for virtual Superpave asphalt mixture design

This study presents an artificial neural network (ANN) model to predict the asphalt mixture volumetrics at Superpave gyration levels. The input data-set needed by the algorithm is composed of gradation of the mix, bulk specific gravity of aggregates, low- and high-performance grade of the binder, binder content of the mix and the target number of gyrations (i.e. N_ini, N_des and N_max). The proposed ANN model uses a three-layer scaled conjugate gradient back-propagation (feed-forward) network. The ANN was trained using data obtained from numerous roads with a total of 1817 different mix designs. Results revealed that the ANN was able to predict V_a within V_a (measured) ± 1.0% range 85–93% of the time and within V_a (measured) ± 0.5% range 60–70% of the time. Currently with the developed ANN model, Superpave mix design can take approximately between 1.5 and 4.5 days, which corresponds to 3–6 days of savings.     

Computational strategy for the crash design analysis using an uncertain computational mechanical model

The framework of this paper is the robust crash analysis of a motor vehicle. The crash analysis is carried out with an uncertain computational model for which uncertainties are taken into account with the parametric probabilistic approach and for which the stochastic solver is the Monte Carlo method. During the design process, different configurations of the motor vehicle are analyzed. Usual interpolation methods cannot be used to predict if the current configuration is similar or not to one of the previous configurations already analyzed and for which a complete stochastic computation has been carried out. In this paper, we propose a new indicator that allows to decide if the current configuration is similar to one of the previous analyzed configurations while the Monte Carlo simulation is not finished and therefore, to stop the Monte Carlo simulation before the end of computation.     

Comparison of experimental pressure drop data for two phase flows to prediction methods using a general model

In this paper, existing and new two phase pressure drop data are used to run an extensive comparison to predictive methods. The database used is for seven refrigerants (R22, R134a, R404A, R407C, R410A, R417A, and R507A) over a wide range of operating conditions. The procedure used for the comparison is a model of general validity since it is independent of the data reduction procedure. Four quoted methods and a new one by Moreno Quibén and Thome are used. The statistical analysis showed that the methods by Grönnerud and by Moreno Quibén and Thome are equally the best. Segregating the data by flow regimes and taking into account for the prediction of the data trends, the method by Moreno Quibén and Thome is able to give reliable predictions in all the range of vapour qualities, especially in the regions of the intermittent flow and dry-out.     

Theoretical and experimental studies on tightly focused vector vortex beams

The high-NA focusing properties of vector vortex beams are studied theoretically and experimentally. The vector vortex beams are generated by space-variant segmented subwavelength metallic gratings first. Then the mathematical expressions for the focused fields are derived based on the vector diffraction theory, and some numerical simulations are presented that show that the focused fields are not dark at the center and the focusing spot size of vector vortex beams with high topological charges approaches the diffraction limitation at high NA. Finally, to verify the theoretical analysis, the tightly focused fields are measured based on a confocal microscopy system when the NA of the objective lens is 0.90. The research results confirm the potential of vector vortex beams in some applications, such as optical trapping, laser printing, lithography, and material processing.