Application of a modified simplex method to the multivariable optimization of a new FIA system for the determination of osmium

A methodology based on the coupling of experimental design and a modified simplex method is proposed for the optimization of a new flow injection-kinetic system for the spectrophotometric determination of Os (IV) with m-acetylchlorophosphonazo, which has for the first time been used as chromogenic reagent in the quantitative analysis of this element. An orthogonal array design is utilized to design the experimental protocol, in which six variables are varied simultaneously, and obtain the initial simplex using 25 experiments. A modified simplex method is applied to continuously optimize the data of the orthogonal array design; the search for optimum conditions of 6 variables using the modified simplex method required only 25 experiments. The efficiency and simplicity of the coupling of the experimental design and the modified simplex method are attractive for the development of new analytical methods. The method has been applied to the determination of Os (IV) in a refined ore as well as in a secondary alloy and provided satisfactory results.     

Application of a modified simplex method to the multivariable optimization of a new FIA system for the determination of osmium

A methodology based on the coupling of experimental design and a modified simplex method is proposed for the optimization of a new flow injection-kinetic system for the spectrophotometric determination of Os (IV) with m-acetylchlorophosphonazo, which has for the first time been used as chromogenic reagent in the quantitative analysis of this element. An orthogonal array design is utilized to design the experimental protocol, in which six variables are varied simultaneously, and obtain the initial simplex using 25 experiments. A modified simplex method is applied to continuously optimize the data of the orthogonal array design; the search for optimum conditions of ¶6 variables using the modified simplex method required only 25 experiments. The efficiency and simplicity of the coupling of the experimental design and the modified simplex method are attractive for the development of new analytical methods. The method has been applied to the determination of Os (IV) in a refined ore as well as in a secondary alloy and provided satisfactory results.     

Design, setup and first results of a miniaturized time-of-flight mass spectrometer with a simple reflector of a new design

A new kind of reflector with only one element has been constructed and used in a miniaturized time-of- flight mass spectrometer. Details from the simulation of the instrument with SIMION and its design are presented and discussed. The instrumental setup is displayed and some first results from measurements are presented. Laser- generated electron ionization (LEI) and resonance-enhanced multi-photon ionization (REMPI) are used for ion production. While both methods yield good mass spectra, the mass resolving power of the instrument is different for both methods. The results of the measurements are compared and discussed with respect to the design. It is found that the resolution of the new instrument is satisfactory for mass spectrometric measurements of small molecules and not limited by the reflector.     

Photosalient Effect of a Diarylethene with a Perfluorocyclohexene Ring

Crystals of a diarylethene with a perfluorocyclohexene ring exhibit a remarkable photosalient effect upon UV light irradiation that is attributed to the structural changes that occur when going from open‐ to closed‐ring isomers in the crystalline state, together with the existence of two conformers with different photoconversions compared with those of a perfluorocyclopentene derivative. Our current results give a design principle for molecular structures so as to achieve the photosalient effect for photochromic crystals.     

Optimization of a direct-current plasma emission echelle spectrometer

Simplex optimization and Box-Behnken partial factorial experimental design techniques were used to optimize the quantitative performance of a direct-current plasma system. Argon pressure and plasma position were selected as variables. The simplex optimization located the region of optimum sensitivity, and the partial factorial design generated quadratic equations describing the relationship between the variables in this area. Results compared well with the results of a univariate search done in the region of optimum sensitivity. Canonical analysis of the response-surface equations showed that there was no unique optimum, but rather a stationary ridge, with combinations of conditions which give similar sensitivities. Studies of response surfaces for imprecision and drift failed identify one optimal region. Comparison of the imprecision and drift contours with the sensitivity results showed that a significant improvement in precision or drift cannot be made by changing the instrumental conditions.     

Optimal design of nanoplasmonic materials using genetic algorithms as a multiparameter optimization tool

An optimal control approach based on multiple parameter genetic algorithms is applied to the design of plasmonic nanoconstructs with predetermined optical properties and functionalities. We first develop nanoscale metallic lenses that focus an incident plane wave onto a prespecified, spatially confined spot. Our results illustrate the mechanism of energy flow through wires and cavities. Next we design a periodic array of silver particles to modify the polarization of an incident, linearly polarized plane wave in a desired fashion while localizing the light in space. The results provide insight into the structural features that determine the birefringence properties of metal nanoparticles and their arrays. Of the variety of potential applications that may be envisioned, we note the design of nanoscale light sources with controllable coherence and polarization properties that could serve for coherent control of molecular, electronic, or electromechanical dynamics in the nanoscale.     

Optimisation of the formulation of a bubble bath by a chemometric approach market segmentation and optimisation

The optimisation of the formulation of a commercial bubble bath was performed by chemometric analysis of Panel Tests results. A first Panel Test was performed to choose the best essence, among four proposed to the consumers; the best essence chosen was used in the revised commercial bubble bath. Afterwards, the effect of changing the amount of four components (the amount of primary surfactant, the essence, the hydratant and the colouring agent) of the bubble bath was studied by a fractional factorial design. The segmentation of the bubble bath market was performed by a second Panel Test, in which the consumers were requested to evaluate the samples coming from the experimental design. The results were then treated by Principal Component Analysis. The market had two segments: people preferring a product with a rich formulation and people preferring a poor product. The final target, i.e. the optimisation of the formulation for each segment, was obtained by the calculation of regression models relating the subjective evaluations given by the Panel and the compositions of the samples. The regression models allowed to identify the best formulations for the two segments ofthe market.     

Development of a Biomimetic MEMS based Capacitive Tactile Sensor

This paper presents the development of a low-cost MEMS based biomimetic tactile device intended to be incorporated as the core element in a biomimetic fingerpad. The developed silicon based sensing devices consist of an array of capacitive sensors with optimized design to measure force ranges encountered during tactile exploration of surfaces with different textures. As with the biological finger, the sensor array contains sensors of different sensitivity and position/orientation, guaranteeing a high informative content of data obtained from surface-finger interaction. This paper presents the design of the device, fabrication processes used and experimental results of sensor performance.     

一种基于电洗脱的核酸纯化回收芯片的设计及优化

提出了一种基于电洗脱原理的核酸纯化回收芯片, 通过对芯片上电极进行适当的切换操作, 可一次完成核酸样品分离和纯化回收. 同时采用数值模拟的方法对纯化回收芯片管道的几何形状及电场分布进行了优化设计, 并进行了实验验证. 实验结果与模拟分析非常吻合, 证明优化设计达到了预期的效果.     

Initial design of a dilute sulfuric acid pretreatment process for aspen wood chips

A preliminary process design for dilute sulfuric acid pretreatment of aspen wood chips in order to obtain fermentable sugars has been prepared and subjected to an economic evaluation. The process design was prepared according to experimental data on the kinetics of dilute sulfuric acid prehydrolysis and particle size effects obtained in this study and our previous work. The initial economic evaluation shows woodchips are 56% of the cost of production, whereas the reactor is only 4%, and the comminution operation is just under 10%, indicating that the process economics are extremely vulnerable to feedstock costs and are thus yield-sensitive. Although chances for major cost improvements by modification of the reactor design and finding alternatives to dry milling of aspen chips to small (20–80 mesh) particles needed for acid penetration and enzymatic saccharification are not great, design improvements of the process will necessitate development of a cheaper acid resistant pretreatment reactor and a less energy intensive comminution system. Experimental results on effects of particle size on the dilute acid pretreatment design are presented.     

The performance and application of a multidimensional system for gas chromatography

We have previously described [1] the design of a simple heart-cuttings device based on the Deans' principle of remote pressure switching [2]. Since that time, further work has been conducted to refine the design of the heart-cutting device and to develop complementary backflushing and cryofocusing units. This paper describes the results obtained from an intensive evaluation of the three modules in various combinations and considers parameters critical to the practical application of multidimensional gas chromatography (MDGC).     

Targeting retroviral Zn finger-DNA interactions: a small-molecule approach using the electrophilic nature of trans-platinum-nucleobase compounds

Noncovalent interactions are ubiquitous in ternary systems involving metal ions, DNA/RNA, and proteins and represent a structural motif for design of selective inhibitors of biological function. This contribution shows that small molecules containing platinated purine nucleobases mimic the natural DNA(RNA)-tryptophan recognition interaction of zinc finger peptides, specifically the C-terminal finger of HIV NCp7 protein. Interaction with platinum results in Zn ejection from the peptide accompanied by loss of tertiary structure. Targeting the NCp7-DNA interaction for drug design represents a conceptual advance over electrophiles designed for chemical attack on the zinc finger alone. These results demonstrate examples of a new platinum structural class targeting specific biological processes, distinct from the bifunctional DNA-DNA binding of cytotoxic agents like cisplatin. The results confirm the validity of a chemical biological approach for metallodrug design for selective ternary DNA(RNA)-protein interactions.     

Development of a Statistical Model for Selective Flocculation of Iron Ore Slimes

In this study, an attempt has been made to identify the significant factors that affect the selective flocculation of iron ore slimes using full factorial design. For this purpose, three factors pH, pulp density, and the flocculant dose were investigated. A 2³ factorial design was employed and the results were analyzed statistically. The result indicated that the pH, pulp density, and their interactions significantly affect the grade of the concentrate. Regression model using the design matrix showed that the predicted values are in well agreement with experimental values for grade and recovery. From the studies, it was possible to enhance the grade to 62.78% Fe with a recovery of 84.23% at pH 10, pulp density 1% and a flocculant dose of 0.03 mg/g.     

Microflow photochemistry—a reactor comparison study using the photochemical synthesis of terebic acid as a model reaction

The continuous-microflow photochemical synthesis of terebic acid from maleic acid was investigated in two different microreactor set-ups. The results were subsequently compared to analogue experiments in a conventional chamber reactor. Based on conversion rates, reactor design and energy efficiency calculations, the simple microcapillary reactor showed the best overall performance.     

Novel method for constructing a large-scale design space in lubrication process by using bayesian estimation based on the reliability of a scale-up rule

A reliable large-scale design space was constructed by integrating the reliability of a scale-up rule into the Bayesian estimation without enforcing a large-scale design of experiments (DoE). A small-scale DoE was conducted using various Froude numbers (X(1)) and blending times (X(2)) in the lubricant blending process for theophylline tablets. The response surfaces, design space, and their reliability of the compression rate of the powder mixture (Y(1)), tablet hardness (Y(2)), and dissolution rate (Y(3)) on a small scale were calculated using multivariate spline interpolation, a bootstrap resampling technique, and self-organizing map clustering. A constant Froude number was applied as a scale-up rule. Experiments were conducted at four different small scales with the same Froude number and blending time in order to determine the discrepancies in the response variables between the scales so as to indicate the reliability of the scale-up rule. Three experiments under an optimal condition and two experiments under other conditions were performed on a large scale. The response surfaces on the small scale were corrected to those on the large scale by Bayesian estimation using the large-scale results and the reliability of the scale-up rule. Large-scale experiments performed under three additional sets of conditions showed that the corrected design space was more reliable than the small-scale design space even when there was some discrepancy in the pharmaceutical quality between the manufacturing scales. This approach is useful for setting up a design space in pharmaceutical development when a DoE cannot be performed at a commercial large manufacturing scale.     

Design of a five-coordinate heme protein maquette: a spectroscopic model of deoxymyoglobin

The substitution of 1-methyl-l-histidine for the histidine heme ligands in a de novo designed four-alpha-helix bundle scaffold results in conversion of a six-coordinate cytochrome maquette into a self-assembled five-coordinate mono-(1-methyl-histidine)-ligated heme as an initial maquette for the dioxygen carrier protein myoglobin. UV-vis, magnetic circular dichroism, and resonance Raman spectroscopies demonstrate the presence of five-coordinate mono-(1-methyl-histidine) ligated ferrous heme spectroscopically similar to deoxymyoglobin. Thermodynamic analysis of the ferric and ferrous heme dissociation constants indicates greater destabilization of the ferric state than the ferrous state. The ferrous heme protein reacts with carbon monoxide to form a (1-methyl-histidine)-Fe(II)(heme)-CO complex; however, reaction with dioxygen leads to autoxidation and ferric heme dissociation. These results indicate that negative protein design can be used to generate a five-coordinate heme within a maquette scaffold.     

Robust stabilization of a chemical reactor

Robust static output feedback control was applied to a continuous stirred tank reactor with parametric uncertainty and multiple steady states in which exothermic reaction takes place. The problem of robust controller design was converted to a solution of linear matrix inequalities and a computationally simple non-iterative algorithm is presented. The possibility of using robust static output feedback for stabilization of reactors with uncertainty and comparison of robust P and PI controllers with an optimal controller is demonstrated by simulation results.     

Radiotracer investigation in a rotary fluidized bioreactor

A rotary fluidized bioreactor (RFBR) designed for treatment of wastewater was required to be investigated for its hydrodynamic behaviour and validation of design. A radiotracer investigation was carried out to measure residence time distribution (RTD) of wastewater in the RFBR using ⁸²Br as a radiotracer. The radiotracer was instantaneously injected into the inlet feed line and monitored at the inlet and outlet of the reactor using collimated scintillation detectors connected to a data acquisition system. The measured RTD data was treated and simulated using a tanks-in-series model and model parameters i.e. number of tanks describing the degree of mixing was obtained. The results of the investigation showed no flow abnormalities and the reactor behaved as an ideal continuously stirred-tank reactor at all the operating conditions. Based on the results, the design of the reactor was validated.     

Miniature time-of-flight mass spectrometer using a flexible circuitboard reflector

An innovative design for a miniature time-of-flight mass spectrometer has been developed employing several newly designed components. These include: (1) a gridless, focusing ion source allowing for the use of very high extraction energies in a maintenance-free design, (2) a new method of construction for an ion reflector using rolled flexible circuitboard material, and (3) an improved center-hole microchannel plate detector assembly that significantly reduces the noise (or 'ringing') inherent in the coaxial design. A prototype time-of-flight instrument was constructed and used to evaluate the performance of these components. Compared to previous designs, results indicate that background noise for data acquired on this instrument is substantially reduced, resolution is improved, and the potential for mass producing this instrument in an inexpensive and rugged package for field-portable and remote installations is significantly enhanced. Copyright 2000 John Wiley & Sons, Ltd.     

Diagnosis of Impurity Levels in a Copolymerization Process

Summary: This work investigates a fault diagnosis problem in the copolymerization process of styrene and methyl methacrylate (STY/MMA). Two topics are discussed in this paper: the system observability and optimal experimental design (OED) to reduce fault misclassification. Lack of observability has been found to be one of the major causes of misclassification in fault diagnosis, which is not remediable by any means other than including the right measurements necessary for the observability. In this work, the system observability has been studied through simulation analysis. Then, two new experimental design methods are proposed to train the projection pursuit regression (PPR) algorithm for fault diagnosis purpose. The new design methods, referred to as Gaussian probability design and Fuzzy boundary design, are compared to a conventional factorial design, to evaluate their performance for the problem under study. The Gaussian probability design is based on the calculation of the probability of an experimental data point near a class boundary belonging to a specific class. The Fuzzy boundary design is based on a bootstrapping technique used in part for the learning process in developing neural network models. It investigates the insufficiency of training data based on the identification of class boundaries by a group of models, such as PPR models. Both Gaussian probability design and Fuzzy boundary design methods automatically search for the sparseness of the training data, and provide guidelines to include pairs of training data on two sides of a class boundary in the areas where the data density is the lowest. The proposed design methods outperform a conventional factorial design by reducing the fault misclassification more effectively with the same amount of additional training data.

Testing data in the process measurement space of temperature vs. conversion.