Processes2015, 3(4), 769-778; doi:10.3390/pr3040769 - published 26 November 2015 Show/Hide Abstract
Abstract: The possibility for simultaneous controlled partition of the biologically active alkaloid S-(+)-glaucine, presented in a crude ionic liquid-aqueous plant extract, and separation of the ionic liquid (IL) employed by means of ionic liquid-based aqueous biphasic systems (IL-ABS) was investigated in this study. The ABS were formed by the addition of inorganic salts with distinct water-structuring properties such as Na2CO3, MgSO4, (NH4)2SO4, and NaH2PO4 to an enriched of glaucine extract of Glaucium flavum Cr. (Papaveraceae). The influence of the salt type and concentration on the phase-forming ability, as well as the pH value on the partition of glaucine between the two phases formed, was comprehensively studied. It was found that the target alkaloid is predominantly transferred into the IL-rich phase, regardless the influential factors. The results obtained were further used as a platform for the development of an improved extractive procedure, ensuring simultaneous glaucine recovery, IL recycling and water removal in a single technological step. Thus, based on the formation of a three-phase system consisting of butyl acetate, IL-rich phase, and salt-rich phase, nearly quantitative recovery of glaucine (>99%), IL recycling (ca. 90%), and water removal (ca. 85%) were achieved by salt-induced separation of the crude plant extract.
Processes2015, 3(4), 749-768; doi:10.3390/pr3040749 - published 10 November 2015 Show/Hide Abstract
Abstract: Water-soluble polymers of acrylamide (AAm) and acrylic acid (AAc) have significant potential in enhanced oil recovery, as well as in other specialty applications. To improve the shear strength of the polymer, a third comonomer, 2-acrylamido-2-methylpropane sulfonic acid (AMPS), can be added to the pre-polymerization mixture. Copolymerization kinetics of AAm/AAc are well studied, but little is known about the other comonomer pairs (AMPS/AAm and AMPS/AAc). Hence, reactivity ratios for AMPS/AAm and AMPS/AAc copolymerization must be established first. A key aspect in the estimation of reliable reactivity ratios is design of experiments, which minimizes the number of experiments and provides increased information content (resulting in more precise parameter estimates). However, design of experiments is hardly ever used during copolymerization parameter estimation schemes. In the current work, copolymerization experiments for both AMPS/AAm and AMPS/AAc are designed using two optimal techniques (Tidwell-Mortimer and the error-in-variables-model (EVM)). From these optimally designed experiments, accurate reactivity ratio estimates are determined for AMPS/AAm (rAMPS = 0.18, rAAm = 0.85) and AMPS/AAc (rAMPS = 0.19, rAAc = 0.86).
Processes2015, 3(4), 731-748; doi:10.3390/pr3040731 - published 3 November 2015 Show/Hide Abstract
Abstract: Polymers are the products of processes and their microstructure can be changed significantly by the reactor systems employed, especially for nonlinear polymers. The Monte Carlo simulation technique, based on the random sampling technique, is used to explore the effect of reactor types on the branched polymer structure, formed through free-radical polymerization with simultaneous long-chain branching and scission, as in the case of low-density polyethylene synthesis. As a simplified model for a tower-type multi-zone reactor, a series of continuous stirred-tank reactors, consisting of one big tank and the same N-1 small tanks is considered theoretically. By simply changing the tank arrangement, various types of branched polymers, from star-like globular structure to a more randomly branched structure, can be obtained, while keeping the following properties of the final products, the monomer conversion to polymer, the average branching and scission densities, and the relationship between the mean-square radius of gyration and molecular weight.
Processes2015, 3(4), 730; doi:10.3390/pr3040730 - published 25 September 2015 Show/Hide Abstract
Abstract: We have become aware that a review paper  recently published in Processes contained a considerable amount of identical text and a similar structure to a previously published review paper , although some novel content was presented, including new citations and a section on smart diagnosis. [...]
Processes2015, 3(3), 701-729; doi:10.3390/pr3030701 - published 21 September 2015 Show/Hide Abstract
Abstract: In recent years, model optimization in the field of computational biology has become a prominent area for development of pharmaceutical drugs. The increased amount of experimental data leads to the increase in complexity of proposed models. With increased complexity comes a necessity for computational algorithms that are able to handle the large datasets that are used to fit model parameters. In this study the ability of simultaneous, hybrid simultaneous, and sequential algorithms are tested on two models representative of computational systems biology. The first case models the cells affected by a virus in a population and serves as a benchmark model for the proposed hybrid algorithm. The second model is the ErbB model and shows the ability of the hybrid sequential and simultaneous method to solve large-scale biological models. Post-processing analysis reveals insights into the model formulation that are important for understanding the specific parameter optimization. A parameter sensitivity analysis reveals shortcomings and difficulties in the ErbB model parameter optimization due to the model formulation rather than the solver capacity. Suggested methods are model reformulation to improve input-to-output model linearity, sensitivity ranking, and choice of solver.