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Objective: Establish a computer model for predicting the inactivation of Zygosaccharomyces rouxii in apple juice by surface discharge plasma (SDP). Methods: The numerical simulation software COMSOL multiphysics was used to model SDP inactivation of Z. rouxii LB. The inactivation efficiency was evaluated under different conditions of discharge voltage, bubble size and sample volume. The model was then validated. Results: SDP was highly effective in deactivating hyperosmotic-resistant yeast in apple juice. The reaction rate coefficient decreased with an increase in the initial concentration of bacteria. Furthermore, the increase in discharge voltage shortened the time needed to inactivate yeasts. Bubble size variations had no significant effect on the inactivation of Z. rouxii LB, and the inactivation time was prolonged with increasing sample volume. The model simulation results agreed with the experimental data.

In this study, the effect of ochratoxin A (OTA) concentration and discharge voltage on the degradation of OTA in artificially contaminated raisins by low-temperature discharge plasma was explore. The results indicated that OTA in raisins contaminated with 50 μg/mL OTA was completely degraded by plasma treatment for 10 minutes at a discharge voltage of 75 kV. The degraded products of OTA were detected by high performance liquid chromatography-quadruple-electrostatic field orbitrap high resolution mass spectrometry. Based on the primary and secondary mass spectra, two major degraded products with m/z 426.071 5 (B) and m/z 158.154 0 (C) and the possible degradation pathway of OTA were speculated. There was no significant change in the physicochemical quality of raisins before and after plasma treatment, and the relative contents of most acids, aldehydes, alcohols and ketones did not significantly change, except for a significant decrease in the contents of 3-methylbutyric acid, acetic acid and caprylic acid among acids, and a significant increase in the contents of formic acid, valeric acid, and 2-ethylhexanoic acid. The research results suggest that low temperature discharge plasma can effectively degrade OTA while having no significant effect on raisin quality, which can provide a reference for OTA degradation in contaminated foods.

The inactivation effect of plasma spray reactor on Zygosaccharomyces rouxii in apple juice was studied as a function of plasma discharge voltages, gas flow rate and liquid flow rate, and the morphological changes of the cells and the effect of this treatment on apple juice quality were evaluated. In this study, a plasma spray reactor was used to treat 0.5 L of apple juice for 30 min at a discharge voltage of 21 kV, a gas flow rate of 150 L/h, and a liquid flow rate of 9.0 L/h. The number of osmotolerant yeast cells in apple juice decreased significantly. Plasma spray reactor treatment caused cell rupture, thus resulting in the inactivation of yeast cells. Under the optimal parameters, this treatment increased the pH of apple juice slightly, but did not cause any significant changes in the titratable acid or reducing sugar concentration (P > 0.05) and resulted in no significant changes in the major major volatile compounds in apple juice. This study may provide a reference for the application of plasma spray reactor in apple juice processing.

A distributed event-triggered protocol is proposed to deal with the time-varying formation control problem of Euler–Lagrange systems with uncertain model parameters in this research. By utilizing the small-gain theorem and matrix transformation, we show the input–output stability of the closed-loop cascade system with Euler–Lagrange dynamics. An event-triggered condition (ETC) is designed by only using the local information of each agent, which avoids the continuous communication in the event detection and excludes the Zeno behavior. Finally, the proposed methods are applied to the practical flight platform for quadrotors. The experiment using three quadrotors in the outdoor environment is demonstrated to test the effectiveness of the formation protocol. [ABSTRACT FROM AUTHOR]

In this article, the ultrafast tracking control for high-order discrete-time multiagent networks is investigated based on the predictive ability of agents. First, in view of the evolution of the original network dynamics, a distributed multistep prediction algorithm is established. Further, a control strategy containing predictive information is presented to achieve the ultrafast tracking control. Second, the problem of ultrafast tracking control with an $H_{\infty }$ performance specification is dealt with. The obtained result indicates that the robustness of the whole multiagent network can be converted into the robustness of multiple separable subsystems. Finally, the optimal ultrafast static tracking control design is provided for the single-integrator network with sampled dynamics. Two simulation cases are carried out to verify the correctness of the obtained theoretical results. [ABSTRACT FROM AUTHOR]

Vision-based formation control offers an alternate solution for unmanned aerial vehicles (UAVs) to work together in the external position system denied environment. In this paper, we present a vision-based formation control strategy with the advantages of high tracking performance and low consumption of communication resources. A vision-based multi-robot localisation methods is applied to get precise position information, and the extended Kalman filter (EKF) is used to fuse measurement data from different sensors. The integral sliding mode controller (ISMC) is utilised to ensure the fast convergence and robustness to the desired formation, and the event-triggered communication scheme is employed to reduce redundant transmission of state information used in the formation controller. The simulation results in Gazebo with a team of three UAVs are given to illustrate the effectness of the proposed control strategy. [ABSTRACT FROM AUTHOR]

This paper studies the multi‐tracking control for high‐order heterogeneous multi‐agent systems under a directed acyclic graph. The authors first convert the multi‐tracking control problem for multi‐agent systems into the zero steady‐state error control problem of some independent subsystems. Based on final‐value theorem and Mason's rule, a sufficient condition for achieving the multi‐tracking control is proposed. It explicitly reveals how the system dynamic and desired object dynamic jointly affect the multi‐tracking control of heterogeneous multi‐agent systems. Meanwhile, a new result on the steady‐state error for multi‐subnetworks is established. Moreover, the multi‐tracking control for heterogeneous multi‐agent systems with time delay is discussed. Some simulations are performed to illustrate the effectiveness of the theoretical results. [ABSTRACT FROM AUTHOR]

This paper deals with the ultra-fast consensus problem of high-order discrete-time multi-agent systems under a unified framework. A multi-step neighbour-error predictive mechanism is established based on the future evolution of the network dynamic without predictive information. By predicting the dynamics of a network several steps ahead and adding this information into the consensus protocol, a novel ultra-fast consensus protocol with the self-feedback term is proposed. The asymptotic convergence factor is improved by a power ofq+ 1 compared to the routine consensus protocol. The ultra-fast consensus algorithm can overcome the influence of communication topology to the convergence speed toward consensus, and solve the difficult problem of selecting the optimal control gain which minimises the asymptotic convergence factor. Moveover, some sufficient conditions for ultra-fast consensus design are given herein. The ones decouple the design of the synchronising gains from the detailed graph properties, and explicitly reveal how the agent dynamic and the communication graph jointly affect ultra-fast consensus of discrete-time multi-agent systems. A simulation is performed to illustrate the effectiveness of the theoretical results. [ABSTRACT FROM PUBLISHER]

Atmospheric cold plasma is a powerful and profitable microbial decontamination technology in the food industry. The microbial load and food matrix have a great influence on the plasma inactivation effect. This study aimed to quantify the effects of initial cell concentration and soluble solids on the inactivation of yeast in apple juice by gas-phase surface discharge plasma. A computer simulation model was developed to predict the inactivation process using commercial finite element software, COMSOL Multiphysics, and the model was verified by experiments. Studies have shown that the inactivation of yeast was affected by the initial cell concentration and soluble solids. These effects were quantified by fitting equations and used as model inputs. The simulation model predicted the D-value of plasma inactivation of yeast under different discharge voltages and apple juice volume, which was verified in experiments. Therefore, the established model can be used for plasma development to predict how the food matrix affects the inactivation process, thereby providing useful and practical tools for amplifying the commercial application of plasma. • A surface discharge voltage plasma deactivation model was developed and verified. • Model correlated the cell concentration and soluble solids with inactivation rates. • The influence of discharge voltage and process capacity was predicted in the model. [ABSTRACT FROM AUTHOR]