A numerical investigation of direct and indirect closed-loop architectures for estimating nonminimum-phase zeros

ABSTRACT

This paper presents a numerical investigation of three direct architectures and three indirect architectures for identifying a plant operating in closed loop. Motivated by adaptive control of systems with nonminimum-phase (NMP) zeros and taking advantage of the fact that zeros are not moved by feedback, the performance metric is the accuracy of the estimates of the NMP zeros of the plant. Assuming known plant order, single-input, single-output, infinite-impulse-response models are constructed in the presence of process and sensor noise. Least squares provides the baseline estimation technique, and prediction error methods are used to account for correlation between the model input and noise. The goal is to compare the accuracy of the NMP-zero estimates obtained from each method and for each architecture.     

New CSPs based on peptidomimetics: efficient chiral selectors in enantioselective separations

Summary Two different families of peptidomimetics have been synthesized and used as chiral selectors for enantioselective chromatography. The functionalization of compounds with multiple nitrogen atoms allows their use in the preparation of chiral stationary phases (CSPs), with acrylic or styril comonomers, in both bead and monolithic formats. Some of these separation media, having the appropriate morphological properties for their use in chromatographic columns, were able to efficiently discriminate enantiomers of aminoacid derivatives and pharmaceuticals such as Oxazepam. Received: 24 September 2001/Revised version: 2 January 2002/ Accepted: 21 January 2002     

Multi-Scale Analysis of Vacuum Contact Drying

The modeling of the unit operation of vacuum contact drying is approached as a multi-scale problem. At the particle assembly length scale, effective transport properties (thermal conductivity, relative gas- and liquid-phase permeability) have been determined computationally by simulations on reconstructed porous media and verified by direct measurements. A distributed-parameter model of vacuum contact drying including liquid and vapor flow and differential energy balance has been formulated and used for the calculation of drying time as function of vacuum level, temperature, vessel diameter, and batch size at the unit operation length scale. Drying curves for a model system of sodium carbonate-isopropanol have been measured experimentally and compared with the model predictions. A very good agreement has been found.     

Expression,Receptor Binding,and Biophysical Characterization of Guinea Pig Insulin desB30: A Monomeric Insulin Variant

Here we report, for the first time, the heterologous expression of desB30 guinea pig insulin (GI desB30) in the yeast Saccharomyces cerevisiae. The affinities of GI desB30 for the insulin receptor A and the IGF‐I receptor were also quantified for the first time. Small‐angle X‐ray scattering and analytical ultracentrifugation studies confirmed that GI desB30 did not form dimers or hexamers, in contrast to human insulin. Sizeexclusion chromatography connected to inductively coupled plasma mass spectrometry revealed that GI desB30 has affinity towards several divalent metal ions. These studies did not indicate the formation of any larger structures of GI desB30 in the presence of various divalent metal ions, but did indicate that GI desB30 has an affinity towards Mn, Co, and Cu ions. Finally, the low affinity for the insulin receptor and the very low affinity for the IGF‐I receptor by GI desB30 were quantified.     

Implementation of best available techniques in the sanitation of relict burdens

The paper deals with the elimination of highly toxic and persistent relict burdens caused by polychlorinated dibenzo-p-dioxins, dibenzofurans, biphenyls, hexachlorobenzene, γ-isomer of hexachlorocyclohexane and other organic halogen derivatives. The technology is used in eliminating the aforementioned contaminants from soil, rubble and metal parts of former machinery with the use of best available techniques. Such a technology has been implemented in the northern part of the town of Neratovice and the Spolana company, plc, which formerly used to be a significant producer of pesticides in the Czech Republic.     

Immobilization of DNA on poly(glycidyl methacrylate-co-ethylene dimethacrylate), bead cellulose and sepharose

Summary The copolymer of glycidylmethacrylate with ethylene-dimethacrylate, its derivatives, bead cellulose and Sepharose were used for immobilization of DNA via new coupling methods: reaction with oxirane, acylhydrazide hydrazide, and diazonium salt. The susceptibility of immobilized DNA for DNAse was tested. The most efficient immobilization was achieved on carriers with acylhydrazide groups. The binding capacity of the carrier and the susceptibility of immobilized DNA for the DNase depends on the length of the spacer. The immobilized DNA is stable in solution for several weeks, and in the lyophilized state for several months.