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Pressure swing adsorption (PSA) technology is used in various applications. PSA is a cost-effective process with the ability to produce high-purity bio-hydrogen (99.99%) with high recovery rates. In this article, a PSA process for the production of bio-hydrogen is proposed; it uses two columns packed with type 5A zeolite, and it has a four-step configuration (adsorption, depressurization, purge, and repressurization) for bio-hydrogen production and regeneration of the beds. The aim of this work is to design and use an active fault-tolerant control (FTC) controller to raise and maintain a stable purity of 0.9999 in molar fraction (99.99%), even with the occurrence of actuator faults. To validate the robustness and performance of the proposed discrete FTC, it has been compared with a discrete PID (proportional–integral–derivative) controller in the presence of actuator faults and trajectory changes. Both controllers achieve to maintain stable purity by reducing the effect of faults; however, the discrete PID controller is not robust to multiple faults since the desired purity is lost and fails to meet international standards to be used as bio-fuel. On the other hand, the FTC scheme reduces the effects of individual and multiple faults by striving to maintain a purity of 0.9999 in molar fraction and complying with international standards to be used as bio-fuel. [ABSTRACT FROM AUTHOR]

The production of biofuels has had a great impact on climate change and the reduction of the use of fossil fuels. There are different technologies used for the separation and production of biofuels, which allow having compounds such as ethanol, methane, oxygen, and hydrogen, one of these promising technologies is the Pressure Swing Adsorption process (PSA). The objectives of this article focus on the production and purification of compounds that achieve purities of 99.5% bioethanol, 94.85% biohydrogen, 95.00% medical oxygen, and 99.99% biomethane through the PSA process; also, a significant review is contemplated to identify the different natural and synthetic adsorbents that have greater adsorption capacity, the different configurations in which a PSA operates are studied and identified, and the different mathematical models that describe the dynamic behavior of all the variables are established that interact in this PSA process, parametric studies are carried out in order to identify the variables that have the greatest effect on the purity obtained. The results obtained in this review allow facilitating the calculation of parameters, the optimization of the process, the automatic control to manipulate certain variables and to achieve the rejection of disturbances to have a recovery and production of biofuels with a high degree of purity. [ABSTRACT FROM AUTHOR]

Bioethanol can be used as fuel obtained from second-generation raw material (cane bagasse) in order not to affect food sovereignty. One of the processes that have achieved a greater production and recovery of bioethanol is pressure swing adsorption (PSA), which uses zeolites to separate and purify the ethanol-water mixture. The aim of this work focuses on implementing a discrete Fault Tolerant Control and discrete PID on a virtual PSA plant for ethanol production maintaining the purity stable under the effects of combined faults in the actuator (flow valve) that can affect the PSA plant. It was observed that both controllers have great performance implementing it in the Hammerstein–Wiener model, but when performing the tests with the PSA plant, the FTC presented greater robustness and performance (achieving a stable purity of 0.9892 molar fraction) to reduce the effects of combined faults considering changes of trajectories, on the other hand, the discrete PID presents difficulties to reduce the effect of the ramp-type fault since the purity drops to 0.82 in molar fraction. The discrete FTC achieves to produce bioethanol (above 99% wt) with purity values that international fuel standards allow. • The PSA plant produces bio-ethanol above 99% wt and meets international standards. • The proposed robust controller reduces the impact of constant and non-constant actuator faults. • The discreet FTC has great performance and robustness since it maintains bioethanol above 99% wt. • The discrete PID control maintains bioethanol of 99% wt only with single faults. [ABSTRACT FROM AUTHOR]

Currently, various light-emitting diode (LED) lighting systems are being developed because LEDs are one of the most used lighting sources for work environments, buildings, homes, and public roads in terms of some of their applications. Similarly, they have low energy consumption, quick responses, and excellent optimal performance in their operation. However, these systems still need to precisely regulate lighting, maintain stable voltage and current in the presence of faults and disturbances, and have a wide range of operations in the event of trajectory changes or monitoring tasks regarding the desired voltage and current. This work presents the design and application of two types of robust controllers (structure-at-infinity control and geometric control) applied to an LED driver using a buck converter. The controllers aim to follow the desired trajectories, attenuate disturbances at the power supply input, and compensate for faults in the actuator (MOSFET) to keep the capacitor voltage and inductor current stable. When comparing the results obtained with the two controllers, it was observed that both present excellent performance in the presence of constant disturbances. However, in scenarios in which variable faults and path changes are implemented, the structure-at-infinity control method shows an overimpulse of output voltage and current ranging from 39 to 42 volts and from 0.3 to 0.45 A, with a margin of error of 1%, and it can generate a failure in the LED driver using a buck converter. On the other hand, when using geometric control, the results are satisfactory, achieving attenuating constant disturbances and variable faults, reaching the desired voltage (40 v to 35 v) and current (0.3 to 0.25 A) with a margin of error of 0.05%, guaranteeing a system without overvoltages or the accelerated degradation of the components due to magnetic conductivity. [ABSTRACT FROM AUTHOR]

This paper introduces a new approach to controlling Pressure Swing Adsorption (PSA) using a neural network controller based on a Model Predictive Control (MPC) process. We use a Hammerstein–Wiener (HW) model representing the real PSA process data. Then, we design an MPC-controlled model based on the HW model to maintain the bioethanol purity near 99 % molar fraction. This work proposes an Artificial Neural Network (ANN) that captures the dynamics of the PSA model controlled by the MPC strategy. Both controllers are validated using the HW model of the PSA process, showing great performance and robustness against disturbances. The results show that we can follow the desired trajectory and attenuate disturbances, achieving the purity of bioethanol at a molar fraction value of 0.99 using the ANN based on the MPC strategy with 94 % of fit in the control signal and a 97 % fit in the purity signal, so we can conclude that our ANN can be used to attenuate disturbances and maintain purity in the PSA process. [ABSTRACT FROM AUTHOR]

In this paper, a discrete state-feedback controller is applied to control the current in power LEDs by using a buck converter. Sufficient conditions for the existence of the controller are given in terms of linear matrix inequalities (LMIs) with D-stability theory. In order to consider the specific closed-loop dynamics of the closed-loop LED driver, the genetic algorithm (GA) technique is applied, as a complement of the D-stability theory. Therefore, the proposed GA technique is used to search offline the optimal closed-loop eigenvalues to have a desired response of the closed-loop system, subject to a proposed cost function equation. The main contribution of this work is the design and the experimental validation of both the state-feedback controller and the GA to achieve the desired closed-loop dynamics of the LED-driver system. Finally, simulations and experimental results are done in order to illustrate the effectiveness of the proposed methodology. [ABSTRACT FROM AUTHOR]

The present paper addresses linear parameter-varying systems with high-order time-varying parameter dependency known as polynomial LPV systems and their controller design. Throughout this work, a procedure ensuring a state-feedback controller from a parameterized linear matrix inequality (PLMI) solution is presented. As the main contribution of this paper, the controller is designed by considering the time-varying parameter rate as a tuning parameter with a continuous control gain in such a way that the closed-loop eigenvalues lie in a complex plane subset, with high-order time-varying parameters defining the system dynamics. Simulation results are presented, aiming to show the effectiveness of the proposed controller design. [ABSTRACT FROM AUTHOR]

An experimental validation of fractional-order PID (FOPID) controllers, which were applied to a two coupled tanks system, is presented in this article. Two FOPID controllers, a continuous FOPID (cFOPID) and a discrete FOPID (dFOPID), were implemented in real-time. The gains tuning process was accomplished by applying genetic algorithms while considering the cost function with respect to the tracking error and control effort. The gains optimization process was performed directly to the two-tanks non-linear model. The real-time implementation used a National Instruments PCIe-6321 card as a data acquisition system; for the interface, we used a Simulink Matlab and Simulink Desktop Real-Time Toolbox. The performance of the fractional controllers was compared with the performance of classical PID controllers. [ABSTRACT FROM AUTHOR]

Synthetic biology aims to develop cells with entirely new functions not found in nature. These functions are manifested through pathways created of genes from other microorganisms linked by molecular techniques such as Bio-Brick Assembly. Some of these linkages can adopt a Boolean behavior and generate what is known as a genetic circuit that is mainly composed of the functional parts of a gene (Promoter, RBS, ORF, Terminator). These interchangeable parts form what is called a Bio-Brick, which can act as a logical gateway by showing an excellent stability and the activation of genetic memory that can lasts after several generations. As a result of the different types of behavior that Bio-Bricks present, they are highly attractive for the industry because it would be enough to choose the best type of circuit for multiple applications both in the biomedical industry (cancer drugs, malaria, specific antibodies, microbiome engineering) or the energy industry in order to produce second-generation biofuels that can compete effectively with fossil fuels; it has also been discovered that due to its usefulness in different fields, it represents a solution to problems such as high greenhouse gas emissions or the current pandemic caused by the appearance of the SARS-CoV-2 virus. Key words: synthetic biology, genetic circuits, Bio-Brick, microbiome engineering, synthetic pathways, biofuel. [ABSTRACT FROM AUTHOR]

Induction motors are the horsepower in the industrial environment, and among them, 3-phase induction motors (3PIMs) stand out for their robustness and standard 3-phase power supply. In the literature, there are many approaches to diagnose faults for the nonlinear 3PIM model, and the vast majority focus on a single motor fault, although others address more faults but at the cost of greater computational complexity. In this sense, one of the methods with less computational load and early detection is the parity equation approach, which is based on analyzing the discrepancy between the input and output signals of a real process and a linear mathematical model to generate a residual signal, which contains important information about the fault and is obtained through a suitable selection of a weighting matrix W to isolate the faults as much as possible. The problem in this case study is that the 3PIM model is a nonlinear system. In this work, the fault detection method based on the parity equations approach applied in the 3PIM is explored using a simplified and proposed model of the 3PIM working in the D-Q synchronous reference frame, which is matched with the direct current motor model to guarantee both the existence of the parity space and to ensure a large set of detectable faults in the 3PIM parameters. Simulation and experimental results validate the proposed scheme and confirm a very simple set of residual equations to guarantee both early detection and a large set of detectable faults in: Stator and rotor resistances, stator and rotor inductances, as well as current, voltage, and speed sensors. Additionally, development of human machine interface (HMI) is implemented to validate the proposed scheme. [ABSTRACT FROM AUTHOR]

• Vermicomposting-tea is an attractive methodology for producing biohydrogen at 25 °C. • Vermicomposting-tea fermentation requires neither salts nor vitamins. • Using molasses as a substrate contributes to the circular economy of this waste. • Upstream processing and optimization were established for scaling-up. • This consortium is capable of tolerating heat-shocks of up to 24 h. This study aimed to establish the optimal operational conditions for hydrogen production using vermicomposting-tea and sugarcane molasses as substrate. The experiments were carried out by triplicate in 110 ml serological bottles, a Box-Behnken design of experiments was performed in anaerobic dark conditions. The maximal hydrogen production (HP), hydrogen production rate (HPR), and hydrogen yield (HY) attained were 1021.0 m l L - 1 , 5.32 m l L - 1 h - 1 , and 60.3 m l L H 2 - 1 / g T C C , respectively. The statistical model showed that the optimal operational conditions for pH, molasses concentration, and temperature were 6.5; 30 % (v/v) and 25 °C. The bioreactor run showed 17.202 L of hydrogen, 0.58 Lh - 1 , and 77.2 m l H 2 g T C C - 1 For HP, HPR, and HY. Chemometric analysis for the volatile fatty acids obtained at the fermentation showed that only two principal components are required to explain 90 % of the variance. The representative pathways for hydrogen production were acetic and butyric acids. This study established the operational conditions for the upstream processing amenable to pilot and industrial-scale operations. Our results add value to molasses within the circular economy for hydrogen production using a novel consortium from vermicompost. [ABSTRACT FROM AUTHOR]

Bio-ethanol has become one of the most important renewable resources, since it comes from renewable raw material, does not contaminate on a large scale, and can be used as an oxygenating additive or fuel applied to bivalent engines. The contribution of this work focuses on designing and applying two different controllers to evaluate the effectiveness and performance: a Fault Tolerant Control (FTC) and Fuzzy PID applied to the Pressure Swing Adsorption process (PSA) with the objective that the PSA process works properly and with the ability to compensate for the faults that have occurred by correcting the control action. As a consequence of this, the process is able to continue producing Bio-ethanol complying with international purity standards. In both controllers, it stabilizes quickly and achieves the reference again eliminating the constant-type faults. However, in the case of a variable-type fault, the Fuzzy PID cannot eliminate the fault, reflecting in the results purities less than 88.4% wt of ethanol. On the other hand, the results obtained using the FTC are favorable since it achieves eliminate the fault, presenting results of purity of 99.5% wt of ethanol and it manages to comply with the international purity standards of ethanol to be used as fuel or oxygenating additive. • The PSA process purifies ethanol to a concentration of 99% wt of ethanol. • The rigorous PSA model acts as a virtual plant finding approximate solutions. • The identified model allows the design of the controllers, applied to the PSA process. • The FTC compensate constant and variable faults. [ABSTRACT FROM AUTHOR]