Temperature control is widely perceived to be superior to direct composition control for the control of dividing-wall distillation columns (DWDCs) due to its advantages in dynamic characteristics. However, because of the limited estimation accuracy to the controlled product purities, the former cannot eliminate the steady-state errors in the maintained product purities as completely as the latter. In order to reduce the steady-state deviations in the maintained product purities, an effective temperature control method is proposed in the current article by means of a kind of simple but effective product quality estimator (PQE). For the proposed PQE, temperatures of three stages located in the controlled column section (TI1, TI2, and TI3) are employed as inputs, and a linear sum of these three inputted stage temperatures (α × TI1 + β × TI2 + γ × TI3) is given as output. A genetic algorithm with an elitist preservation strategy is used to optimize the locations of the three stage temperat... [more]

Products are manufactured as printed electronics through electro-conductive ink having properties suitable for flexible substrates. As printing process conditions affect the quality of the electronic properties of the final devices, it is essential to understand how the parameters of each process affect print quality. Spray printing, one of several printing processes, suits flexible large-area substrates and continuous processes with a uniform layer for electro-conductive aqueous ink. This study adopted the spray printing process for cellulose nanofiber (CNF)/carbon nanotube (CNT) composite conductive printing. Five spray parameters (nozzle diameter, spray speed, amount of sprayed ink, distance of nozzle to substrate, and nozzle pressure) were chosen to investigate the effects between process parameters and electrical properties relating to the morphology of the printing products. This study observed the controlling morphology through parameter adjustment and confirmed how it affects t... [more]

The stabilization problems for time-delay stochastic systems with multiplicative noise in the control variable are investigated in this paper. The innovative contributions are described as follows. Since the past work on stabilization is based on some delay-dependent algebraic Riccati equation (DARE), how to numerically calculate the stabilizing solution remains an unsolved and open problem. On the one hand, an iterative algorithm for computing the unique stabilizing solution of DARE is proposed, while the convergence property is also proved. On the other hand, the concepts of critical stabilization and essential destabilization are proposed as a supplement to stochastic stabilization in terms of spectrum technique. Moreover, the Lyapunov-based necessary and sufficient conditions are developed.

The aim of this study was to evaluate the effects of a complex Bacillus subtilis additive on the fermentation quality and bacterial community during the ensiling process of whole-plant corn silage (WPCS). The pH values of WPCS treated with the B. subtilis inoculant decreased faster than those of the control without inoculant, and significantly higher contents of lactic acid (LA) and acetic acid (AA) were observed. After 45 days of ensiling, the LA contents reached 7.95% (w/w). In the treatment group, the neutral detergent fibre (NDF) and acid detergent fibre (ADF) contents decreased significantly compared to the control, and the degradation rates of the NDF and ADF were 26.52% and 27.34% after 45 days, respectively. The deoxynivalenol (DON) content in the treatment group decreased to 205.67 μg/kg, which was significantly lower than the content of 382.51 μg/kg in the control group. The results indicated the positive effect of the B. subtilis inoculant in improving WPCS fermentation, esp... [more]

In this article, an improved constraint dealing method and an extended state space model-based constrained predictive functional control (PFC) approach is developed for the denitration process in cement production. To improve the control effect of the presented strategy, first, an enhanced form-based state space model in which the changes of the output predictions can be regulated to achieve smoother system dynamics is constructed. Then, a modified constraint dealing scheme, which integrates the relaxation factors to improve the success probability of solving the relevant optimization, is also introduced for the proposed method. On the basis of the two merits, better ensemble control performance is anticipated. Simulations on the regulation of the NOx concentration in the denitration process prove the validity of the proposed constrained PFC strategy.

Product quality is an important part of enterprise competitiveness. Product processing is the key process of quality formation. In smart factories, the improvement of data acquisition and processing capability provides a basis for data-based quality control. In order to reduce the occurrence of product quality problems, we abstracted the product processing process as a data processing unit, abstracted the process of changing the product quality state as a process of the processing quality characteristics data, divided the measured value of quality characteristics into three states according to the fluctuation of the measured value of product quality characteristics, and then the classification model of process equipment parameters was established. The experimental results show that the error rate of the real-time dynamic prediction of quality characteristics based on equipment parameters was acceptable, and its prediction could be used as a reference in real production. The research co... [more]

Today, more than ever, the popularity of decentralized payment systems has risen, creating an outbreak of new cryptocurrencies hitting the market. Unique websites have been staged for each cryptocurrency, where information and means for mining cryptocurrencies are available daily. People visit those cryptocurrency websites either from desktop or mobile devices. Thus, the impulsion for appropriate promotion of cryptocurrency websites and customer factors affecting it rises. The above process increases cryptocurrency organizations’ website visibility, raising the need for customer relationships and satisfaction optimization concerning organizations’ supply chain strategy. Research data were collected from 10 well-known cryptocurrency websites, regarding mobile and desktop devices, in 180 days, regarding on-site web analytics. Therefore, a model consisting of three stages was applied. Starting phase of the model pertains to statistical and regression analysis of cryptocurrency web analyti... [more]

With the development of hydropower, the heat problem of a rotor cannot be ignored. This paper presents a topology of an evaporative cooling system for rotors. The system seals the pole coil in a tank and immerses the coil in the insulating coolant with a suitable boiling point. The latent heat of vaporization during the boiling of coolant is used to control the temperature rise of the pole coil. After explaining the circulation principle of the system, the effectiveness of the cooling system is verified by experiments. A small-scale experimental platform has been set up to test the effectiveness of the new topology. The comparison experiment with air-cooling shows that the phase change cooling system can not only provide hundreds of times the heat transfer capacity of air-cooling, but also the temperature rise of the coil is half that of air cooling. Based on the experimental results, the calculated formula of the heat transfer coefficient of the evaporative cooling system in the rotat... [more]

(1) Background: A proposal for the automatic control of sugar cane honey factories based on simulation with real data is presented. (2) Methods: The P&ID diagram of the artisanal process is designed, as well as the measurement and control systems of the different process variables. A data acquisition and monitoring system is proposed with all the required equipment. Using GNU Octave software, the process was simulated, where the transfer functions and parameters of the different stages were determined. The transient responses of these systems are determined before step-jump type disturbances, as well as that of the controllers. (3) Results: A correct adjustment of the controllers is obtained, indicating those that work in a stable way before disturbance variations in the real ranges of plant work. (4) Conclusions: Simulation of controllers before different forcing functions in the ranges of the operating parameters allowed for establishing dynamic responses of each one, demonstrating t... [more]

Sucrose contributes to the key physical and sensory characteristics of cookies. Due to the negative health effects associated with excess sucrose consumption, the replacement of sucrose in baking applications is of interest. In this study, nine variations of rolled cookies were prepared (n = 3) using a sucrose control (C), Splenda for baking (SB), Equal for baking (EB), Truvia (TR), Sweet’N Low (SNL), and 1:1 (wt%) mixtures of sweeteners and sucrose (S). The cookies were characterized by a width-to-thickness (W/T) ratio, moisture loss, color, hardness, and fracturability. The W/T ratios of TR (5.7) and TR + sucrose (6.6) were similar, the closest to C (7.7), and bigger than (p < 0.05) all other treatments. Color was not affected (p > 0.05) by the sugar type or concentration. C showed the greatest hardness (5268 N), and SNL had the greatest fracturability (8667 N). Overall, regarding physiochemical characteristics, TR + sucrose (1:1 replacement) and SB (100% replacement) were the closes... [more]

For β-cell replacement therapies, one challenge is the manufacturing of enough β-cells (Edmonton protocol for islet transplantation requires 0.5−1 × 106 islet equivalents). To maintain their functionality, β-cells should be manufactured as 3D constructs, known as spheroids. In this study, we investigated whether β-cell spheroid manufacturing can be addressed by a stirred-tank bioreactor (STR) process. STRs are fully controlled bioreactor systems, which allow the establishment of robust, larger-scale manufacturing processes. Using the INS-1 β-cell line as a model for process development, we investigated the dynamic agglomeration of β-cells to determine minimal seeding densities, spheroid strength, and the influence of turbulent shear stress. We established a correlation to exploit shear forces within the turbulent flow regime, in order to generate spheroids of a defined size, and to predict the spheroid size in an STR by using the determined spheroid strength. Finally, we transferred th... [more]

Indocyanine green (ICG) is a near-infrared (NIR) organic reagent for clinical bioimaging and phototherapy. It is a suitable photosensitizer for photodynamic antimicrobial chemotherapy (PACT). In this study, various ICG-loaded nanofibrous membranes were prepared. The water vapor transmission rate (WVTR) of SF/PLGA/20ICG was 3040.49 ± 157.11 g·m−2 day−1, which allowed the maintenance of a humid environment above the wound. The growth inhibition rates for S. aureus and E. coli were 91.53% and 87.95%, respectively. The nanofibrous membranes exhibited excellent antimicrobial performance. Cellular experiments showed that the nanofibrous membranes have good cytocompatibility and antitumor efficacy. SF/PLGA/20ICG showed good potential for application in wound healing and cancer therapy.

Water pollution is an important aspect of a national water treatment. Sudden water safety incidents are random and destructive, often bringing about huge losses of life and property. Due to the uncertainty of sudden water pollution, it is difficult to respond in a timely and rapid manner. Emergency personnel must deal with emergencies quickly and effectively to reduce the harm caused by these emergencies. The randomness and uncertainty of sudden water pollution events make emergency work more complicated; it is difficult for current emergency plans to play guiding roles in complex responses. The decision-making and use of traditional water safety procedures largely depend on the experiences of command personnel, as well as on the emergency plan, which often has poor applicability. This can result in ineffective implementation of emergency actions and use of resources stemming from the high subjectivity and low efficiency of emergency plans. In this paper, we summarize previous research... [more]

This study examines the dynamics in a brushless DC motor (BLDCM) and methods used to control potentially chaotic behavior or behavior similar to chaotic processes in these systems. Bifurcation diagrams revealed complex nonlinear behaviors over a range of parameter values. In the resulting bifurcation diagram, period-doubling bifurcation, period-three bifurcation, and chaotic behavior can clearly be seen. We used Lyapunov exponents and Lyapunov dimensions to show the occurrence of chaos in a BLDCM. We then used the state feedback method to control chaos behaviors in the same BLDCM. Numerical simulations show the feasibility of the suggested means. Analysis of robustness against parametric perturbation in a BLDCM was performed from the perspective of Lyapunov stability theory and by using numerical simulations. We believe that studying the nonlinear dynamics and controlling chaos in BLDCMs will help to advance the development of high-performance electric vehicles.

An interval type-2 (IT-2) fuzzy control design method is developed to solve the formation and containment problem of nonlinear multi-boiler systems. In most practical industrial systems such as airplanes, vessels, and power plants, the boiler system often exists as more than one piece of equipment. An efficient control theory based on the leader-following multi-agent system is applied to achieve the control purpose of multiple boiler systems simultaneously. Moreover, a faithful mathematical model of the nonlinear boiler system is extended to construct the multi-boiler system so that the dynamic behaviors can be accurately presented. For the control of practical multi-agent systems, the uncertainties problem, which will deteriorate the performance of the whole system greatly, must be considered. Because of this, the IT-2 Takagi−Sugeno (T−S) fuzzy model is developed to represent the nonlinear multi-boiler system with uncertainties more completely. Based on the fuzzy model, the IT-2 fuzzy... [more]

Lithium-ion (Li-ion) batteries have been utilized increasingly in recent years in various applications, such as electric vehicles (EVs), electronics, and large energy storage systems due to their long lifespan, high energy density, and high-power density, among other qualities. However, there can be faults that occur internally or externally that affect battery performance which can potentially lead to serious safety concerns, such as thermal runaway. Thermal runaway is a major challenge in the Li-ion battery field due to its uncontrollable and irreversible nature, which can lead to fires and explosions, threatening the safety of the public. Therefore, thermal runaway prognosis and diagnosis are significant topics of research. To efficiently study and develop thermal runaway prognosis and diagnosis algorithms, thermal runaway modeling is also important. Li-ion battery thermal runaway modeling, prediction, and detection can help in the development of prevention and mitigation approaches... [more]

This paper studies hydraulic cylinder position adjustment controlled by an on−off valve. The aim of this paper is to develop a method of position control for a hydraulic cylinder based on input and output pressure under the mutual coupling feedback of the load and flow, especially in multi-actuator coupling control scenarios. This method can solve the problem of position evaluation and hydraulic cylinder tracking in relation to position detection without a displacement sensor and provide the possibility of automatic adjustment of hydraulic support in the process of intelligent mining. First of all, according to the flow continuity equation and Navier−Stokes equation, a flow model with inlet and outlet pressure is derived. Secondly, the effectiveness of the flow resistance characteristic curve of differential valve is verified by experimental and theoretical analysis. Finally, through experimental verification, when the system pressure is larger than 10 MPa, the error between the actual... [more]

This paper focuses on the frequency domain fluid−structure interaction (FSI) vibration characteristics of aircraft hydraulic pipe with complex constraints. The linear partial differential fourteen-equation model is applied to describe the nonlinear FSI dynamics of pipes conveying fluid with high-speed, high-pressure, a wide Reynolds number, and the vibration frequency range. The excitation, complex boundary, and middle constraint models of liquid-filled pipes are analytically established and added into the global model of the pipe system. These resulting models are solved by the improved Laplace transform transfer matrix method (LTTMM) in the frequency domain. Then, the dynamic response characteristics of an aircraft hydraulic pipe containing diverse constraints are investigated numerically and experimentally under four types of working conditions, and the improvement conditions for the numerical instabilities are presented. In general, the present method is highly efficient and conven... [more]

This study proposes an induction heating system with maximum power-point tracking (MPPT) control strategy. The system architecture adopts a 1.3 kW full-bridge series resonant circuit with a step-down transformer and adjusts the operating frequency by a microcontroller unit to improve the heating efficiency. Secondly, the proposed MPPT control strategy based on induction heating uses the relationship between the operating frequency and the system heating temperature to find the operating frequency corresponding to the maximum power point (MPP) quickly. Then, an additional hill-climbing algorithm adjusting the duty cycle is applied to reach the duty cycle corresponding to the MPP. Under the simulation and actual experimental measurement, the traditional control strategy has 76% and 68% at 500 and 750 degrees, respectively, and it takes 320 s for the system to reach 750 degrees. By contrast, the proposed MPPT control strategy achieves 96% efficiency when the system heating temperature is... [more]

The three-phase separator is one of the most important pieces of equipment in the combined station of the oilfield. The control level of the oil−water interface directly affects the energy consumption of the subsequent production of the combined station and the effect of oil, gas and water separation. In order to avoid these situations, the Siemens PLC control system, configuration software WinCC and MATLAB were used. The OPC technology is used to connect communication between WinCC and MATLAB, and the genetic algorithm in MATLAB is used to obtain the optimal separation height of the oil−water interface under the produced liquid in different periods. Subsequently, through the Siemens PLC system and WinCC configuration software, the automatic control of the three-phase separator is achieved, and finally the water content of crude oil is significantly reduced. The system provides a visual interface function. In the future, it will also provide an effective simulation platform for the the... [more]

Recent research has seen an interest in the condition monitoring (CM) approach for aluminium electrolytic capacitors (AEC), which are present in switched-mode power supplies and other power electronics equipment. From various literature reviews conducted and from a failure mode effect analysis (FMEA) standpoint, the most critical and prone to fault component with the highest percentage is mostly capacitors. Due to its long-lasting ability (endurance), CM offers a better paradigm for AEC due to its application. However, owing to severe conditions (over-voltage, mechanical stress, high temperature) that could occur during use, they (capacitors) could be exposed to early breakdown and overall shutdown of the SMPS. This study considered accelerated life testing (electrical stress and long-term frequency testing) for the component due to its endurance in thousands of hours. We have set up the experiment test bench to monitor the critical electrical parameters: dissipation factor (D), equiva... [more]

A controlled and self-assembled micromachining system was built to fabricate a mico/nanoscale monolayer patterned array on a silicon surface using a diamond tip. The process was as follows: (1) we preprocessed a silicon wafer to obtain a hydrogen-terminated silicon surface; (2) we scratched three rectangular arrays of 10 μm × 3 μm with a spacing of 2 μm on the silicon surface with a diamond tip in 1-octadecene solution; the Si-H bonds were broken, and silicon free radicals were formed; (3) the 1-octadecene molecules were connected with silicon atoms based on Si-C covalent bonds, and the 1-octadecene nano monolayer was self-assembled on the patterned arrays of the silicon surface. Atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and Sessile water contact angles were used to detect and characterize the self-assembled monolayers (SAMs). The XPS results showed that the Si2p peak and the O1s peak were significantly decreased after self-assembly; however, the C1s peak w... [more]

Nucleation is the formation of a new phase that has the ability to irreversibly and spontaneously grow into a large-sized nucleus within the body of a metastable parent phase. In this experimental work, the effect of wettability on the incipiation of vacuum-driven bubble nucleation, boiling, and the consequent rate of evaporative cooling are studied. One hydrophilic (untreated), and three hydrophobic (chlorinated polydimethylsiloxane, chlorinated fluoroalkylmethylsiloxane and (heptadecafluoro-1,1,2,2-tetrahydrodecyl)triethoxysilane) glass vials of different wettabilities were filled with degassed deionized water and exposed to a controlled vacuum inside a transparent desiccator. The vacuum was increased by 34 mbar abs. (1 inHg rel.) steps with 15-min waiting period to observe bubble nucleation. The average onset pressures for gas/vapor bubble nucleation in CM, CF, and HT vials were 911 ± 30, 911 ± 34, and 925 ± 17 mbar abs., respectively. Bubble nucleation was not observed in hydrophil... [more]

This article presents the results of the analysis of experimental data that were obtained during industrial tests of an adjustable asynchronous traction electric drive of a shuttle car for the mining industry. During these tests, by changing the parameters of the stator voltage, the stator currents of the induction motor were optimized when the load changes over a wide range (from −1.5 Tn to + 1.5 Tn). The authors managed to significantly reduce the effective values of the stator currents of the motor, but at the same time it was found that, with the load and even the rate of its change, oscillations of the effective values of currents with variable amplitude and frequency occur. It turned out to be very difficult to explain these oscillations and the variability of their parameters using traditional mathematical methods for describing processes in asynchronous electric motors. Vector equations and diagrams are valid only at constant frequencies of the stator voltage and, in the modes... [more]

Nowadays, the proportional−integral−derivative (PID) controller dominates industrial process control. Because of the compromise between parameters, its tuning is still a challenge for practitioners. A reference model (RM)-based PID controller—the desired dynamic equational (DDE) PID controller—is regarded as a viable alternative since it can readily eliminate the compromise. However, how to design its desired dynamic equation remains an unsolved problem which limits the application of DDE PID controllers in large-scale industrial systems. Therefore, this paper studies the desired dynamic selection of DDE PID controllers and proposes a simple and practical selection procedure without using the accurate plant model. Simulations, experiments and filed tests demonstrate the convenience and advantages of the proposed method, thus making DDE PID an effective controller type which is specifically appealing to engineers. Moreover, the successful application of DDE PID controllers to a high-pre... [more]