Fault recovery in control systems : a discrete event system approach

Fault recovery is a challenging task that is crucial in achieving stringent reliability and safety goals. In this thesis, the problem of fault recovery is studied in discrete-event systems (DES), assuming permanent failures. A diagnosis system is assumed to be available to detect and isolate faults with a bounded delay. Thus, the combination of the plant and diagnosis system can be thought of having three modes: normal, transient, and recovery. Initially the plant is in the normal mode. Once a failure occurs, the system enters the transient mode. After the failure is diagnosed by the diagnosis system, the system enters the recovery mode. This framework does not depend on the diagnosis technique used, as long as the diagnosis delay is bounded. As a result, the diagnosis and control problems are almost decoupled. In general, for each mode there is a set of specifications that have to be met. We propose a modular switching supervisory scheme. The proposed framework contains one normal-transient supervisor and multiple recovery supervisors each corresponding to a particular failure mode. Once a fault is detected and isolated by the diagnoser, the normal-transient supervisor is removed from the feedback loop and one of the recovery supervisors will take sole control of the system. The issue of non-blocking is studied and it is shown that essentially if the system under supervision is non-blocking in the normal mode, then it will remain non-blocking during the recovery procedure. Supervisor admissibility is also studied. This approach is developed for untimed DES and then extended to timed DES. In the process, previous results on supervisor design for untimed DES with partial observation are extended to timed DES. Various examples from manufacturing and process control are provided to illustrate the approach

Silver nanoparticles modified titanium carbide MXene composite for RSM-CCD optimised chloride removal from water

Unsafe levels of chloride in drinking water can make it unpalatable, susceptible to infrastructure corrosion and prone to heavy metals mobility. Conventional chloride mitigation strategies are subjected to inefficient performance and costly operation, necessitating innovations for more sustainable, affordable, and scalable technologies. In this study, silver nanoparticles-modified Ti3C2 MXene nanocomposite (AgMX) is synthesised via dry impregnation method for effective removal of chloride ion from water. The composite physicochemical properties were thoroughly characterised using various analytical techniques, including TEM, SEM, XRD, EDS, BET, zeta potential and pHpzc analysis. The experimental testing was optimised using CCD-RSM method in terms of adsorbent dosage (0.2–2 g/L), reaction time (1–17 min), and chloride concentration (10–90 mg/L). Under optimal conditions (adsorbent:1.55 g/L, time: 12.19 min, & concentration: 52.17 mg/L), a promising chloride removal of 91.8 % was achieved. Langmuir model showed the best fit to adsorption isotherm (R2: 0.9852) comparing to Freundlich and Dubinin-Kaganer-Radushkevich (DKR) isotherms, while pseudo-second-order kinetic model offered the closest data to the experimental results (R2: 9893) compared to the pseudo-first-order, Elovich and Intraparticle diffusion models R2: 0.2335,0.1212 and 0.2050, respectively. The composite reusability and regeneration potential after four repeated cycles were found practically efficient as ≥ 68 % and ≥ 84 %, respectively. The outcomes of this study can demonstrate the efficiency of the formulated composite as a promising material for the sustainable treatment of chloride-contaminated water

Exact solutions to the perturbed nonlinear Schrodinger's equation with Kerr law nonlinearity by using the first integral method

WOS: 000297030000005The first integral method is an efficient method for obtaining exact solutions of some nonlinear partial differential equations. In this paper, the first integral method is used to construct exact solutions of the perturbed nonlinear Schrodinger's equation (NLSE) with Kerr law nonlinearity. It is shown that the proposed method is effective and general

Large Scale Linear Programming in the Windows and Linux computer operating systems

In this study, calculations necessary to solve the large scale linear programming problems in two operating systems, Linux and Windows 7 (Win), are compared using two different methods. Relying on the interior-point methods, linear-programming interior point solvers (LIPSOL) software was used for the first method and relying on an augmented Lagrangian method-based algorithm, the second method used the generalized derivative. The performed calculations for various problems show the produced random in the Linux operating system (OS) andWin OS indicate the efficiency of the performed calculations in the Linux OS in terms of the accuracy and using of the optimum memory

Efectos de los metales pesados sobre las propiedades antibacteriales de Verbascum speciosum Schard

The effects of heavy metals, from Hame-Kasi Mine in Western Iran, on the in vitro antibacterial effects of the aqueous extracts of polluted Verbascum speciosum Schard. (Scrophulariaceae) flowers in different concentrations were investigated. Determination of heavy metals (Cu, Fe, Mn, and Zn) in collected soils and plants from the control and mine area was performed using Flame Atomic Absorption Spectrophotometry.The control sites were from 5 km distance of the mine. The antibacterial activity of the extracts was examined against 10 bacterial strains (three Gram-positive and seven Gram-negative bacteria). Results showed high Fe, Mn and Zn concentration in polluted soil, and high Fe concentration in polluted plant in compared to control samples. The control and polluted aqueous extract appeared to be highly effective on Salmonella paratyphi in different concentrations, but non effective on six other bacteria strains.Se investigó los efectos de los metales pesados provenientes de la mina Hame-Kasi en el oeste de Irán sobre los efectos antibacteriales in vitro de los extractos acuosos florales en diferentes concentraciones del control y contaminado de Verbascum speciosum Schard. (Scrophulariaceae). La determinación de los metales pesados (Cu, Fe, Mn y Zn) en suelos y plantas colectados del área de control y de la mina se realizó mediante la espectrofotometría de absorción atómica de llama. Los controles estuvieron a 5 km de la mina. La actividad antibacteriana de los extractos se evaluó contra 10 cepas de bacterias (tres Gram-positivas y siete bacterias Gram-negativas). Los resultados mostraron mayores concentraciones de Fe, Mn y Zn en los suelos contaminados y mayor concentración de Fe en las plantas contaminadas en comparación con las muestras del control. El extracto acuoso del control y del contaminado pareció ser altamente efectivo sobre Salmonella paratyphi en diferentes concentraciones, pero no efectiva en las otras seis cepas bacterianas

New exact traveling wave solutions for DS-I and DS-II equations

WOS: 000309691600009In this present work, the simplest equation method is used to construct exact solutions of the DS-I and DS-II equations. The simplest equation method is a powerful solution method for obtaining exact solutions of nonlinear evolution equations. This method can be applied to nonintegrable equations as well as to integrable ones.TUBITAK (The Scientific and Technological Research Council of Turkey)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK)The authors are very grateful to the referees for their detailed comments and kind help. First author thanks TUBITAK (The Scientific and Technological Research Council of Turkey) for their financial support and grant for research entitled "Integrable Systems and Soliton Theory" at University of South Florida