Permeability and Diffusivity of d-Limonene Vapor in Polymeric Sealant Films

The permeability (P) and Diffusivity (D) of d-limonene vapor in nine polymeric sealant films were measured and compared at a vapor concentration of 0.719 mg/L over the range 25–45°C. The sorption of d-limonene (q_s) was determined by a temperature programmed desorption (TPD) method. Equations to predict P and D for the different films were derived as a function of q_s or temperature (T_mp) of differential scanning calorimeter measured melting points (DSCmp) of the films. Results indicated a tendency of test films with smaller values of q_s and higher T_mp to have higher barriers against loss of d-limonene due to absorption.     

Sorption of Volatile Compounds in Aqueous Solution by Ethylene-Vinyl Alcohol Copolymer Films

Sorption of volatile compounds by ethylene-vinyl alcohol copolymer (EVOH) films from an aqueous solution was investigated to evaluate the merit of their use for food packaging. With regard to EVOH, equilibrium swelling values gave rise to a bimodal solubility parameter distribution with maxima at δ values of 8.5 assigned to ethylene units and 14.5 to vinyl alcohol units. Comparing distribution ratios of EVOH with those of middle-density polyethylene (MDPE), the ratios were 1:100 for terpene hydrocarbons, 1:10 for esters, 1:2 for alcohols, and almost 1:1 for aldehydes. By biaxial orientation of EVOH film, the sorption could be depressed below 60%. These results suggested EVOH films are more appropriate than MDPE for food container lining.     

Discrete-time optimal regulator with closed-loop poles in a prescribed region

This paper is concerned with the problem of designing discrete-time optimal control systems with closed-loop poles in a prescribed region of stability. First, by utilizing the property of the Riccati equation with Q being zero, we develop a method for allocating poles in a disc with centre at the origin of the complex plane and with radius less than 1. Secondly, we deal with pole placement in a disc which is in the unit disc and also contacts the point 1 + j0 of the complex plane. To this end, a bilinear transformation and continuous-time regulator results are employed. In each case, the radius of the disc can be specified as a design parameter, and the weighting matrices of the performance index are obtained to fulfil the desired pole allocations. The design procedures are also illustrated by numerical examples.     

Parameter identification for a two-dimensional image fieId†

This paper presents a new approach to image enhancement based on a maximum likelihood identification method. It is assumed that the images are corrupted by a white gaussian noise field. A two-dimensional extension of the classical ARMA model is developed as a mathematical model for the image fields. Since the maximum likelihood identification leads to a parametric optimization problem, Davidon's algorithm is applied for numerical solutions. The advantage of the present method is that the enhanced images based on the predicted estimates are directly obtained from the noise-corruptod images, so that the autocovariance function of the original image is not required. To improve the quality of the enhanced images, a filtering algorithm is also derived. Digital simulation studies are carried out for various artificial images to show the feasibility of this approach.     

Robust Kalman filter for linear discrete-time system with gaussian sum noises

This paper considers the filtering problem for discrete-time linear systems where the distributions of the process and observation noises are of gaussian sum distributions. Since the gaussian sum noise can be considered to be a sample from one of the gaussian distributions forming the gaussian sum, we define the distribution selection parameters that specify sample noises from the gaussian sum distribution. By using the maximum a posteriori (MAP) estimates of the selection parameters, a robust state estimation algorithm combined with the Kalman filter is developed. Simulation studies are also included to show the effectiveness of the present algorithm.