Cyber-Physical Systems (CPSs) represent systems where computations are tightly coupled with the physical world, meaning that physical data is the core component that drives computation. Industrial ...automation systems, wireless sensor networks, mobile robots and vehicular networks are just a sample of cyber-physical systems. Typically, CPSs have limited computation and storage capabilities due to their tiny size and being embedded into larger systems. With the emergence of cloud computing and the Internet-of-Things (IoT), there are several new opportunities for these CPSs to extend their capabilities by taking advantage of the cloud resources in different ways. In this survey paper, we present an overview of research efforts on the integration of cyber-physical systems with cloud computing and categorize them into three areas: (1) remote brain, (2) big data manipulation, (3) and virtualization. In particular, we focus on three major CPSs namely mobile robots, wireless sensor networks and vehicular networks.
In this work, we show how optimal control theory can be used to optimize membrane filtration processes. The objective is to determine the optimal switching between filtration and backwash sequences ...in order to maximize the net water production per membrane area of microfiltration or ultrafiltration systems over a given period of time. The optimal solutions, whether the backwash flux is constant or variable, have been derived for a membrane filtration process operating at constant transmembrane pressure using a class of filtration models defined only by their qualitative behaviors. The optimal solution is applied in a simulation case study by considering a specific model validated on data recovered from the literature. The robustness of the approach has been evaluated for different disturbances.
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•Complexation-UF was successfully used to separate α-CD from a α-CD/β-CD mixture.•Igepal/CD molar ratio, assuring complete β-CD complexation, was determined.•Pressure, Igepal/β-CD and ...α-CD/β-CD ratio influence the α-CD separation factor.
This work is aimed at developing a new process to separate α-cyclodextrin (CD) from binary α-CD/β-CD mixtures. To achieve this objective, a membrane process was designed with water as solvent and using the selective accommodation of a guest Igepal Co-890 (IG) within the β-CD cavity. In the first part, host-guest inclusion study suggested the formation of IG2/β-CD complex in presence of IG excess. Moreover, increasing IG/CD molar ratio to 1.5 leads to the complete complexation of β-CD while α-CD remains free. The second part was devoted to the separation of α- and β-CD using UF membranes (GH and GK from GE-Osmonics). The influence of parameters including membrane molecular weight cut-off (MWCO), transmembrane pressure (ΔP), IG/β-CD and α-CD/β-CD molar ratios, was investigated. MWCO, ΔP, IG/β-CD and α-CD/β-CD molar ratios respectively of 1000 Da, 2 bar, 1.5 and 11:89 are the optimized values to reach an α-CD separation factor as high as 38. The experimental data fits very well with predicted values calculated using the parameters found in the complexation study and rejection of single solutions indicating that selectivity predominantly originates from steric exclusion of species by membrane GH.
Optimal Control of Membrane-Filtration Systems Kalboussi, Nesrine; Rapaport, Alain; Bayen, Terence ...
IEEE transactions on automatic control,
05/2019, Letnik:
64, Številka:
5
Journal Article
Recenzirano
Odprti dostop
This paper studies an optimal control problem related to membrane-filtration processes. A generic mathematical model of membrane fouling is used to capture the dynamic behavior of the filtration ...process, which consists in the attachment of matter onto the membrane during the filtration period, and the detachment of matter during the cleaning period. We consider the maximization of the net water production of a membrane filtration system (i.e., the filtrate) over a finite time horizon, where the control variable is the sequence of filtration/backwashing cycles over the operation time of process. Based on the Pontryagin's maximum principle, we characterize the optimal control strategy and show that it exhibits a singular arc. Moreover, we prove the existence of an additional switching curve before reaching the terminal state, and also the possibility of having a dispersal curve as a locus where both the different strategies are optimal.
An optimal control strategy for municipal wastewater MBR treatment was applied to investigate its efficiency in minimizing the pumping energy of the system. Based on a simple mathematical model to ...capture the dynamic evolution of the TransMembrane Pressure (TMP), an optimal switching instant between filtration/backwash was determined to reduce the supplementary pumping energy caused by fouling for a predefined net permeate volume. A MBR pilot treating municipal wastewater was used to generate dynamic data of TMP. The pilot was operated with two different strategies: a classical strategy with known operating conditions (10 min filtration and 45 s backwash) and an optimal strategy where the frequency was determined based on adjustment of model parameters. Results demonstrated that a satisfactory agreement was achieved between experimental data and model prediction. The optimal strategy was then applied experimentally on the MBR pilot. The two strategies were compared in terms of energy consumption and fouling degree. The results showed the feasibility of the optimal solution and its reliability to reduce the pumping energy of the system by 7 % and decrease residual fouling by 14 % compared with a classical strategy.
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•Optimal control approach was used to reduce pumping energy induced by fouling.•The optimal strategy proved its efficiency to optimize the backwash frequency.•The optimal solution is adapted to be applied in practice.•Lower residual fouling rate are observed with optimal backwash strategy.•Pump energy consumption is saved by 7 % compared to the classical backwash strategy.
This work deals with the membrane fouling mode and the unclogging in seawater ultrafiltration process. The identification of the fouling mechanism by modeling the experimental flux decline was ...performed using both the classical models of Hermia and the combined models of Bolton. The results show that Bolton models did not bring more precise information than the Hermia's and the flux decline can be described by one of the four Hermia's models since the backwash interval is ${\leq}60$ min. An experimental screening study has been then conducted to choose among 5 parameters (backwash interval, duration, pulses and the flow-rate or injected hypochlorite concentration) those that are the most influential on the fouling and the net water production. It has emerged that fouling is mainly affected by the backwash interval; its prolongation from 30 to 60 min engenders an increase in the reversible fouling and a decrease in the irreversible fouling. This later is also significantly reduced when the hypochlorite concentration increases from 4.5 to 10 ppm. Moreover, the net water production significantly increases with increasing the filtration duration up to 60 min and decreases with decreasing the backwash duration and backwash flow-rate from 10 to 40 s and from 15 to ${\geq}20L.min^{-1}$, respectively.
This work deals with the membrane fouling mode and the unclogging in seawater ultrafiltration process. The identification of the fouling mechanism by modeling the experimental flux decline was ...performed using both the classical models of Hermia and the combined models of Bolton. The results show that Bolton models did not bring more precise information than the Hermia’s and the flux decline can be described by one of the four Hermia’s models since the backwash interval is ≤ 60 min. An experimental screening study has been then conducted to choose among 5 parameters (backwash interval, duration, pulses and the flow-rate or injected hypochlorite concentration) those that are the most influential on the fouling and the net water production. It has emerged that fouling is mainly affected by the backwash interval; its prolongation from 30 to 60 min engenders an increase in the reversible fouling and a decrease in the irreversible fouling. This later is also significantly reduced when the hypochlorite concentration increases from 4.5 to 10 ppm. Moreover, the net water production significantly increases with increasing the filtration duration up to 60 min and decreases with decreasing the backwash duration and backwash flow-rate from 10 to 40 s and from 15 to ≥ 20 L.min-1, respectively. KCI Citation Count: 0
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