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Abstract  

A method for determination of the composition of binary mixtures of a metal or radionuclide species by optimized repeated two-phase separations (SORTS) was proposed and theoretically substantiated. Its principle consists in repeated equilibration of two immiscible phases, one being the original liquid or solid matrix with minimal adjustment of its composition and varying the phase ratio (separation stage cut) as the optimized parameter. The batch separation technique may consist in the repeated solvent extraction or aqueous biphasic distribution, or in the replicate equilibration with solvent or leaching solution. Results of SORTS can be presented e.g. by Tukey box diagrams as the characteristic fingerprints of original species composition.

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both OFAT (one factor at a time), and DOE were both applied to conclude optimum separation conditions. Face centered cube response surface experimental design was chosen to carry out the optimization experiments studying the effect of six factors

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Abstract  

The production of astatine isotope 211 for nuclear therapeutic applications requires to minimize its210At contaminations. This work provides a numerical programme, allowing an optimization of bombarding conditions of the cyclotron isotope production in order to obtain high yields of the mean isotope as well as lowest contaminations of other by-produced nuclides. Finally, results are compared with experimental values.

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Abstract  

XRFS can be successfully used for routine on-line analysis of different agricultural products, for instance where food quality control is necessary. The optimization of the system for such purposes and the results obtained are shown on the example of the analysis of coffee.

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Herein, we illustrate how microreactor technology can be used as a tool for reaction screening and optimization, in addition to improving the reaction chemistry. We report the in-situ generation of azo compounds by reactive quenching of diazonium intermediates in microreactors. This involves an electrophilic aromatic substitution reaction, namely, an azo-coupling reaction performed in continuous-flow systems in the presence of a phase transfer catalyst with great emphasis on compounds that do not easily couple. Capitalizing on the benefits of a large surface area and the short molecular diffusion distances observed in microreactors, in-situ phase transfer catalyzed azo-coupling reaction of diphenylamine to p-nitroaniline was investigated. A rapid and easy optimization protocol was established which yielded a 99%, 22%, and 33% conversion of diphenylamine, carbazole, and triphenylamine, respectively, in approximately 2.4 min.

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Summary

Charged-coupled device (CCD) noise can be a serious problem during videoscanning, especially when scanning dark plates with weakly fluorescent spots. The proper denoising of videoscans inside mathematical environments is a critical part of any advanced chemometric processing. The paper reports comparison and optimization of representative videoscan denoising by different techniques. Several kind of filters (averaging, circular, Gaussian, Savitzky-Golay, median, Wiener, FIR) and wavelet shrinkage (twelve mother wavelets from the Daubechies, Symmlet, and Coiflet family, five decomposition levels, and soft/hard thresholding) were optimized against noise autocorrelation or mean-squared error to the reference image. The reference image was obtained by grabbing and averaging 256 CCD frames. The median filter is the winner of the competition; other filters except Gaussian and wavelet shrinkage at high decomposition level are also sufficient and good ways of videoscan denoising. The Gaussian filter and wavelet shrinkage at low decomposition level performed worst and could not be recommended.

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Random Amplified Polymorphic DNA (RAPD) technique is a powerful tool for genetic studies. It can be also applied for determination of bacterial species. The goal of this work was to optimize conditions for RAPD reaction, and to obtain RAPD patterns specific for some plant-associated bacteria. RAPD could be a good choice for screening and preliminary bacterial determination. Application of RAPD can determine that some of bacterial species are not reason of infection, and make additional tests for them unnecessary. This can provide time, labor, and as well as money saving, which is important particularly if expensive tests are applied. Optimization of reaction conditions in this work made possible good repeatability of RAPD electrophoretic patterns for particular bacterial species.

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Abstract  

In radiochemical analysis, specially by using high resolution alpha-spectrometry, a key issue is the determination of the radiochemical yield. Radiochemical yield allows to determine the concentration of the radionuclide of interest and the quality of the chemical separation. To determine the radiochemical yield it is necessary to know the solid state detector efficiency, which can be obtained by calibration with a circular calibrated source. In this paper the optimization of the parameters affecting both the calibration and measurement of a source by alpha-spectrometry is described. The optimization is based on two sets of data: experimental and theoretical. Experimental data were obtained from the calibration of the solid state detector with four calibrated 241Am sources. Theoretical data were calculated by geometry formulas and were verified experimentally.

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Analytical as well as computer aided thermal optimization of a construction of a stripegeometry double-heterostructure GaAs/(AlGa)As diode laser were performed in the present work. The influence of various construction parameters of the laser on its thermal resistance is shown.

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Abstract  

Excitation functions fornatZn (p, xn) and (p, pxn) nuclear reactions in the 5–45 MeV proton energy range were measured. Evaluations were made both of target thickness and proton energy in order to optimize the67Ga production rate, at the same time minimizing contamination by the66Ga. Optimal irradiation conditions, depending both on the beam current available and on the power dissipated into the target were determined.

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