Prediction of the maximum spoutable height in spout-fluid beds

The development of the semi-theoretical correlation in Hadzisdmajlovic et al. (1983) for predicting the maximum spoutable height in a spout-fluid bed, is observed to involve certain discrepancies. Based on their experimental data, a new correlation is proposed.     

Parametric modeling of somatosensory evoked potentials

In this paper, we examine methods of characterizing somatosensory evoked potentials (SEP's) in both the time and frequency domains. We have found that the truncated impulse response (TIR) method produced an accurate time domain model of the SEP signals at model orders greatly reduced from the original state space matrix. The TIR method was valuable for smoothing signals that were slightly corrupted by noise. In this case, the simulated data sequence was close to the original data sequence in the mean squared error sense. For signals that were greatly corrupted by noise, the TIR method was not able to perform as well. Therefore, the TIR method was not a feature extraction method but was valuable for data simulation. In the frequency domain, we have used the autoregressive moving average model (ARMA) to parameterize the SEP signal. An overdetermined set of Yule-Walker equations was created to determine the autoregressive (AR) parameters of the original data with the model order established by the singular value decomposition. From these AR parameters, a residual time series was generated which was used to find the moving average parameters. The resulting ARMA model was used to produce a simulated data sequence. The frequency domain characteristics of the simulated sequence and the corresponding power spectral density of the ARMA filter were very close to the periodogram of the original data sequence. Accurate parameterization was achieved for the SEP waveforms at low filter lengths.     

Minimum effort factor approach for sensor-based control of a four-joint 6-dof redundant manipulator

A sensor-driven control model and a minimum effort control algorithm in terms of time and energy expended during the execution of a movement strategy are described and validated for a multijointed cooperating robotic manipulator. Considering smooth, human-like (anthropomorphic) movements, using joint motion profiles achievable in real time as well as sensory information from all joints, and evaluating the total work expended by each manipulator joint during the execution of a movement strategy, a minimum effort motion trajectory is synthesized to precisely and efficiently position the robotic arm end-effector. This sensor-based approach significantly reduces the computational requirements for such cooperative motion. The minimum effort control algorithm generates several human-like arm movement strategies and selects the best strategy on the basis of expendable effort. The algorithm has an inherent basis to deal with obstacles in an efficient way. Detailed examples are described from the simulation studies. © 1994 John Wiley & Sons, Inc.     

智能工程与控制技术：历史,发展与未来

本文综述了智能工程和控制技术的发展历程和基本问题。文中着重论述了人工智能在过程控制系统中的必要性及开发实时智能控制系统的步骤；对符号推理系统、耦合推理系统、人工神经网络和集成分布式智能系统的特点和局限进行了比较。最后讨论了计算机集成过程系统（ＣＩＰＳ）的基本问题、基础技术和发展前景。     

Effect of pressure gradient on MHD boundary layer over a flat plate

Summary The magnetohydrodynamic (MHD) boundary layer flow over a flat plate is examined here for two cases, viz. a uniform free-stream velocity and a uniform hydrostatic pressure. The nonlinear boundary layer equations are solved using a reliable finite-difference method. The boundary layer physical parameters such as skin-friction coefficient, displacement, momentum and energy thicknesses of the boundary layer are determined. It is found that the normal surface velocity gradient decreases with the local magnetic interaction parameter for the cases of a uniform hydrostatic pressure, whereas in the case of a uniform free-stream volocity it increases with the interaction parameter.     

Intracellular sequestration of sodium by a novel Na+/H+ exchanger in yeast is enhanced by mutations in the plasma membrane H+-ATPase. Insights into mechanisms of sodium tolerance

Sodium tolerance in yeast is disrupted by mutations in calcineurin, a Ca2+/calmodulin-dependent protein phosphatase, which is required for modulation of Na+ uptake and efflux mechanisms. Five Na+-tolerant mutants were isolated by selecting for suppressors of calcineurin mutations, and mapped to the PMA1 gene, encoding the plasma membrane H+-ATPase. One mutant, pma1-alpha4, which has the single amino acid change Glu367 --> Lys at a highly conserved site within the catalytic domain of the ATPase, was analyzed in detail to determine the mechanism of Na+ tolerance. After exposure to Na+ in the culture medium, 22Na influx in the pma1 mutant was reduced 2-fold relative to control, consistent with a similar decrease in ATPase activity. Efflux of 22Na from intact cells was relatively unchanged in the pma1 mutant. However, selective permeabilization of the plasma membrane revealed that mutant cells retained up to 80% of intracellular Na+ within a slowly exchanging pool. We show that NHX1, a novel gene homologous to the mammalian NHE family of Na+/H+ exchangers, is required for Na+ sequestration in yeast and contributes to the Na+-tolerant phenotype of pma1-alpha4.     

橡塑共混热塑性弹性体的形态结构与性能

综述了影响共混热塑性弹性体的形态结构与性能的主要因素。