Feedback induction of limit cycle in a bioreactor: controlling towards scale-down

"The feedback stabilization of periodic orbits (induction of limit cycle) via PI-like control is proposed as plausible tool for scale-down studies. An isothermal continuous stirred tank bioreactor (CSTB), with nonideal mixing, is studied. Kinetics is assumed to be governed by Haldane law. The Ready-to-use equations for selecting the control gains are given. Thus, osccilatory behavior with arbitrary frequency and amplitude can be induced into the PI-controlled CSTB.

Detection of mixed-culture growth in the total biomass data by wavelet transforms

"We have shown elsewhere that the presence of mixed-culture growth of microbial species in fermentation processes can be detected with high accuracy by employing the wavelet transform. This is achieved because the crosses in the different growth processes contributing to the total biomass signal appear as singularities that are very well evidenced through their singularity cones in the wavelet transform. However, we used very simple two-species cases. In this work, we extend the wavelet method to a more complicated illustrative fermentation case of three microbial species for which we employ several wavelets of different number of vanishing moments in order to eliminate possible numerical artifacts. Working in this way allows to filter in a more precise way the numerical values of the Hölder exponents. Therefore, we were able to determine the characteristic Hölder exponents for the corresponding crossing singularities of the microbial growth processes and their stability logarithmic scale ranges up to the first decimal in the value of the characteristic exponents. Since calibrating the mixed microbial growth by means of their Hölder exponents could have potential industrial applications, the dependence of the Hölder exponents on the kinetic and physical parameters of the growth models remains as a future experimental task.

PI-controlled bioreactor as a generalized Liénard system

"It is shown that periodic orbits can emerge in Cholette’s bioreactor model working under the influence of a PI-controller. We find a diffeomorphic coordinate trans-formation that turns this controlled enzymatic reaction system into a general-ized Lie´nard form. Furthermore, we give sufficient conditions for the existence and uniqueness of limit cycles in the new coordinates. We also perform numerical simu-lations illustrating the possibility of the existence of a local center (period annulus). A result with possible practical applications is that the oscillation frequency is a function of the integral control gain parameter.

Cellular automata modeling of continuous stirred tank reactors

"The classical dynamical systems model of continuous stirred tank reactors (CSTR) in which a first order chemical reaction takes place is reformulated in terms of stochastic cellular automata by extending previous works of Seyborg [3] and Neuforth [4] by including the feed flow of chemical reactants. We show that this cellular automata procedure is able to simulate the dilution rate and the mixing process in the CSTR, as well as the details of the heat removal due to the jacket. The cellular automata approach is expected to be of considerable applicability at any industrial scales and especially for any type of microchemical systems.

Application of multifractal wavelet analysis to spontaneous fermentation processes

"An algorithm is presented here to get more detailed information, of mixed cul-ture type, based exclusively on the biomass concentration data for fermentation processes. The analysis is performed with only the on-line measurements of the re-dox potential being available. It is a two-step procedure which includes an Artiffial Neural Network (ANN) that relates the redox potential to the biomass concen-trations in the first step. Next, a multifractal wavelet analysis is performed using the biomass estimates of the process. In this context, our results show that the redox potential is a valuable indicator of microorganism metabolic activity during the spontaneous fermentation. In this paper, the detailed design of the multifractal wavelet analysis is presented, as well as its direct experimental application at the laboratory level.

Software Components for Smart Industry Based on Microservices: A Case Study in pH Control Process for the Beverage Industry

[EN] Modern industries require constant adaptation to new trends. Thus, they seek greater flexibility and agility to cope with disruptions, as well as to solve needs or meet the demand for growth. Therefore, smart industrial applications require a lot of flexibility to be able to react more quickly to continuous market changes, offer more personalized products, increase operational efficiency, and achieve optimum operating points that integrate the entire value chain of a process. This requires the capture of new data that are subsequently processed at different levels of the hierarchy of automation processes, with requirements and technologies according to each level. The result is a new challenge related to the addition of new functionalities in the processes and the interoperability between them. This paper proposes a distributed computational component-based framework that integrates communication, computation, and storage resources and real-time capabilities through container technology, microservices, and the publish/subscribe paradigm, as well as contributing to the development and implementation of industrial automation applications by bridging the gap between generic architectures and physical realizations. The main idea is to enable plug-and-play software components, from predefined components with their interrelationships, to achieve industrial applications without losing or degrading the robustness from previous developments. This paper presents the process of design and implementation with the proposed framework through the implementation of a complex pH control process, ranging from the simulation part to its scaling and implementation to an industrial level, showing the plug-and-play assembly from a definition of components with their relationships to the implementation process with the respective technologies involved. The effectiveness of the proposed framework was experimentally verified in a real production process, showing that the results scaled to an industrial scale comply with the simulated design process. A qualitative comparison with traditional industrial implementations, based on the implementation requirements, was carried out. The implementation was developed in the beverage production plant "Punta Delicia", located in Colima, Mexico. Finally, the results showed that the platform provided a high-fidelity design, analysis, and testing environment for cyber information flow and their effect on the physical operation of the pH control.This work has been supported by for research cooperation between Universidad de Colima (Mexico), Universidad Autonoma de Occidente (Colombia), Universitat Politecnica de Valencia (Spain) and the juice production plant Punta Delicia located in Colima, Mexico.Serrano-Magaña, H.; González-Potes, A.; Ibarra-Junquera, V.; Balbastre, P.; Martínez-Castro, D.; Simó Ten, JE. (2021). Software Components for Smart Industry Based on Microservices: A Case Study in pH Control Process for the Beverage Industry. Electronics. 10(7):1-21. https://doi.org/10.3390/electronics1007076312110

Effects of Fruit Position in Standard Place Pack Cartons and Gamma 1 Irradiation on the Postharvest Quality of ‘Barnfield’ Navel Oranges

The objective of this study was to determine if oranges in the top and bottom layers within a Standard Place Pack were impacted differently by irradiation after long-term storage. ‘Barnfield’ Navel oranges were packed in Standard Place Pack cartons and treated with 0, 0.15, or 1 kGy of gamma irradiation. The fruit were stored for 3 weeks at 5 °C and then for 1 week at 20 °C. After storage, the fruit from the top and bottom layers were separately evaluated for quality. The development of stem-end rind breakdown (SERB) was the main cause of quality loss and was greater in irradiated fruit in the top layer. Fruit in the bottom layer showed more physical damage (flattening) but lower incidence of SERB. The changes in individual sugar content were minimal but significant for layer. The content of individual organic acids was consistently lower in irradiated fruit from the bottom layer. Layer type showed a stronger effect on phenolic compounds than irradiation dose. The tristimulus color, total soluble solids, titratable acidity, and firmness of fruit were not influenced by irradiation dose or layer type. The results show that damage in irradiated Navel oranges depends on dose and layer, with the top layers showing greater physiological damage and bottom layers showing more physical damage