Time-critical energy minimization protocol using PQM (TCEM-PQM) for wireless body sensor network

Wireless body sensor network (WBSN) provides a sophisticated monitoring environment without disturbing the daily subject activity. The WBSN increases the mobility of the subject without being restricted inside the hospital environment. However, resources like limited power and transceiver capability limit the movement of the subject. Providing an energy-efficient scheme will provide extended network lifetime and limits the frequency of recharging the battery. This subject condition modelled as a Markov model with normal and abnormal states. The transition from the normal state to abnormal state is predicted through Markov process. The sensor nodes monitoring the subject status remade to sleep state during the reasonable condition, and during the abnormal state, all the nodes awakened. This sleep–wake methodology with priority queuing model is studied in this paper and implemented in MATLAB. The priority queuing model provides a novel solution for time-critical applications. The proposed TCEM-PQM provides reduced time delay when compared to PQM routing protocol. The time delay reduced for critical applications and the policy suits monitoring environment and healthcare applications. The proposed model is simulated with Markov model.

     

Truss optimization with natural frequency constraints using generalized normal distribution optimization

The newly proposed Generalized Normal Distribution Optimization (GNDO) algorithm is used to design the truss structures with optimal weight. All trusses optimized have frequency constraints, which make them very challenging optimization problems. A large number of locally optimal solutions and non-convexity of search space make them difficult to solve, therefore, they are suitable for testing the performance of optimization algorithm. This work investigates whether the proposed algorithm is capable of coping with such problems. To evaluate the GNDO algorithm, three benchmark truss optimization problems are considered with frequency constraints. Numerical data show GNDO’s reliability, stability, and efficiency for structural optimization problems than other meta-heuristic algorithms. We thoroughly analyse and investigate the performance of GNDO in this engineering area for the first time in the literature.

     

Oxygen-rich TiO2 decorated with C-Dots: Highly efficient visible-light-responsive photocatalysts in degradations of different contaminants

Providing novel photocatalysts with high photocatalytic efficiency is of great significance. In the present work, hydrogen peroxide and carbon dots (C-Dots) were utilized to enhance the photocatalytic performance of TiO₂ under visible light. The fabricated TiO₂-peroxo/C-Dots photocatalysts were analyzed by XRD, HRTEM, SEM, EDX, BET, FT-IR, XPS, PL, UV–Vis DRS, EIS, and photocurrent density. Photocatalytic abilities of the nanocomposites were evaluated by photocatalytic removal of RhB, MO, MB, fuchsine, and Cr (VI) upon visible-light illumination. The results demonstrated that the binary nanocomposites exhibited remarkably enhanced photocatalytic activity compared with the TiO₂ and TiO₂-peroxo photocatalysts. The best photocatalytic performance was obtained using 0.75?mL of C-Dots, which was approximately 79.2, 17.1, 71.4, and 40.5 times higher than the pure TiO₂ for degradations of RhB, MO, MB, and fuchsine, respectively. Furthermore, the TiO₂-peroxo/C-Dots nanocomposites exhibited high stability in consecutive photocatalytic processes. Based on the results, the TiO₂-peroxo/C-Dots photocatalyst is expected to become a promising photocatalyst for practical applications in water purification.     

Effective removal of a cobalt‐tetrasulfonated phthalocyanine dye from an aqueous solution with a novel modified chitosan‐based superabsorbent hydrogel

Industrial wastewaters from the Merox process are heavily polluted by toxic cobalt‐tetrasulfonated phthalocyanine (CoTsPc) dye catalyst, and in this article, we describe the synthesis of novel chitosan hydrogels and their adsorption capabilities against CoTsPc as biosorbents. In this study, novel chitosan hydrogels were crosslinked by 3,3′,4,4′‐tetracarboxybenzophenone dianhydride and used for the first time. The adsorption capacities of the hydrogels were significantly improved, and they exhibited excellent sorption behavior with ammonium sulfate modification. The adsorption behavior was observed to be pH dependent, and the optimum pH was found to be 8. Moreover, the swelling studies indicated that the hydrogels are superabsorbent. The reusability of these dye‐adsorbent hydrogels was also evaluated. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46167.     

The Role of the Collisions on the Weibel Instability Growth Rate in the Fast Ignition Scenario

In this paper, the effects of Coulomb elctron-ion collisions and plasma density gradient, \(\eta\), on the Weibel instability in inertial confinement fusion are investigated. The results are indicative that the corrected collision of Weibel instability growth rate of the relativistic region near the corona, \(\eta >0.3\), increases with increasing relativistic parameter, \(\upgamma\). Also, near the fuel core as \(\eta\) goes down, the corrected collisional growth rate decreases with increasing \(\upgamma\) for \(\mathrm{{\upgamma }}<6\) and and increases with increasing \(\upgamma\) for \(\upgamma >6\). Therefore, for \(\upgamma <6\), the effect of collision and fuel density gradient tend to stabilize the Weibel instability in fuel core, with the Weibel growth rate below the collisionless value. Also deposition condition of relativistic electron beam energy can be shifted to the fuel core for the suitable ignition.     

Modelling and shape optimization of an actuator

The aim of this work is to optimize an actuator design so that the flow profile at its exit section is as close as possible to a target profile. The method is founded on the penalization and level-set methods to solve direct and inverse problems on Cartesian meshes The optimization process is written and applied both for Stokes and Navier-Stokes flows. The results show that the method can be successfully applied to the non linear problem to improve the flow profile of an actuator even if the target cannot be totally reached.     

A dynamic programming approach for finding shortest chains in a fuzzy network

Graph theory has numerous applications to problems in systems analysis, operations research, transportation, and economics. In many cases, however, some aspects of a graph-theoretic problem may be uncertain. For example, the vehicle travel time or vehicle capacity on a road network may not be known exactly. In such cases, it is natural to make use of fuzzy set theory to deal with the uncertainty. Here, we are concerned with finding shortest chains in a graph with fuzzy distance for every edge. We propose a dynamic programming approach to solve the fuzzy shortest chain problem using a suitable ranking method. By using MATLAB, two illustrative examples are worked out to demonstrate the proposed algorithm.     

Notes for Contributors /

Abstract

The aim of this study was to depict a framework for development of integrated intelligent human engineering environment in complex critical systems. Conventional health, safety and environment (HSE) are a widely used approach to enhance reliability and safety of complex systems. The integrated health, safety, environment and ergonomics management system (HSEE‐MS) is defined however as integration of conventional HSE with ergonomics.

To show the need for and superiority of HSEE over conventional HSE, a gas treatment company in Iran was studied. Evaluation of ergonomics was carried out by 195 male employees responding to questionnaires.

The integrated HSEE system introduces a unique, effective and systemic mechanism, which integrates the structure of the human and organizational systems with a conventional HSE system. It is utilized to enhance reliability, availability, maintainability and safety through the proposed integrated framework of this study.     

Path Planning for Autonomous Mobile Robots Using the Boundary Integral Equation Method

Path planning is a fundamental problem in mobile robotics. The objective of path planning is to find a sequence of states that carries a robot from some start state to the goal while avoiding obstacles. This paper focuses on point-to-point path planning, ie., developing a path between given points in a known environment with obstacles. A novel environment representation method is introduced which utilizes the Boundary Integral Equation (BIE) method to map the environment into continuous Harmonic potential fields. Different mappings and mechanisms for utilizing these mappings for path planning are developed, and a collection of path planning algorithms are described which exploit the properties of Harmonic fields and the computational efficiency of the BIE method.     

Investigation of the fracture mechanism and mechanical properties of polystyrene/silica nanocomposite in various silica contents

There is limited research on the effect of silica on the mechanical properties of polystyrene. For this lack of information, this study has focused on the fracture mechanism and mechanical properties of Polystyrene/silica nanocomposite. Transmission electron microscopy showed proper dispersion of nanoparticles in PS matrix in both low and high filler loadings. Scanning electron microscopy, TOM micrography, and non-contact surface profiler were used to study the fracture surface and fracture mechanism characteristics of the nanocomposite. It seems that the debonding mechanism is an important mechanism in toughening of Polystyrene/silica nanocomposites. In addition, mechanical behavior of the samples was investigated. Tensile, flexural, and compressive strength and also impact and plain-strain fracture toughness of nanocomposite samples showed different behaviors in low and high nanoparticle loadings and interestingly, we found an optimum value less than 2% for nanoparticle loading in which we observed the highest improvement in mechanical properties of the nanocomposite.