Effect of the fatigue data editing technique associated with finite element analysis on the component fatigue design period

The present study concerns development of accelerated fatigue design time based finite element analysis (FEA) through a combination of the fatigue data editing (FDE) technique and FEA. Country road, pavement and highway fatigue data histories were collected using a fatigue data acquisition system. The component durability was evaluated using both original and editing fatigue data signals. Both signals showed a large difference in the CPU time. Furthermore, the histories were successfully edited by presenting the predicted amount of the fatigue damage as the original histories. As a consequence of application for automotive lower suspension arm, this technique can be applied in performing a fatigue history editing, especially in compression of data set. Briefly, design time was saved based on FDE technique associated with FEA.     

Power-domain non orthogonal multiple access (PD-NOMA) in cooperative networks: an overview

Wireless Networks - Non-orthogonal multiple access (NOMA) scheme is emerging as a favourable multiple access scheme for future 5G networks. Compared to orthogonal multiple access techniques, NOMA...     

Nonlinear elastic–plastic stress investigation for two interacting 3‐D cracks in offshore pipelines

Under continuous loading conditions, small closely distanced cracks can grow and coalesce into a large one that may subsequently pose a threat to the integrity and safety of structures. Although many research works were carried out for predicting fatigue growth of multiple cracks, few papers focusing on nonlinear elastic–plastic analysis of multiple cracks' fracture behaviours can be referred to. In this study, 3‐D elastic–plastic investigation has been performed on fracture behaviours of two collinear cracks located in offshore pipelines. The influences of the cracks configuration, the separation distance and internal pressure of the pipeline on the crack behaviours are investigated. On the basis of the numerical results, a new strain‐based crack tip opening displacement estimation method is proposed for assessing the fracture behaviour of flawed pipelines with two interacting collinear cracks.     

Characterization,antibacterial and in vitro compatibility of zinc–silver doped hydroxyapatite nanoparticles prepared through microwave synthesis

We investigated the possibility of enhancing hydroxyapatite (HA) bioactivity by co-substituting it with zinc and silver. Zn–Ag–HA nanoparticles were synthesized by using the microwave-assisted wet precipitation process, and their phase purity, elemental composition, morphology, and particle size were analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). FTIR, XRD, and EDX results showed the characteristic peaks of the Zn–Ag–HA structure, while SEM results demonstrated that the nanoparticles were of spherical shape with a particle size of 70–102 nm. Antibacterial tests of the nanoparticles revealed their antibacterial activity against Staphylococcus aureus and Escherichia coli. By using simulated body fluid (SBF), an apatite layer formation was observed at 28 days. In vitro cell adhesion assay confirmed the cell attachment of normal human osteoblast (NHOst) cells to the disc surface. MTT [(3(4, 5-dimethylthiazol-2-yl)-2, 5 diphenyltetrazolium bromide] assay indicated that the cells were viable, and the cells proliferated faster on the disks than on the control surface due to the presence of metal ions. In conclusion, the novel Zn–Ag–HA nanoparticles were found to be compatible with in vitro experiments and having potential antibacterial properties. Therefore these nanoparticles could be a promising candidate for future biomedical applications.     

Microwave synthesis of magnetically separable ZnFe2O4-reduced graphene oxide for wastewater treatment

A magnetically separable ZnFe₂O₄-reduced graphene oxide (rGO) nano-composite was synthesised via a microwave method. Field emission scanning electron microscopy images of the nano-composite showed a uniform dispersion of nanoparticles on the rGO sheets. The performance of the nano-composite in wastewater treatment was assessed by observing the decomposition of methylene blue. The nano-composite showed excellent bifunctionality, i.e. adsorption and photocatalytic degradation of methylene blue, for up to five cycles of water treatment when illuminated with light from a halogen bulb. In contrast, water treatment with the nano-composite without illumination and the illuminated rGO, with no decoration of nanoparticles, diminished significantly after the first treatment. The reclamation of the ZnFe₂O₄-rGO nano-composite from treated water could be easily achieved by applying an external magnetic field.     

Ozone-induced changes of antioxidant capacity of fresh-cut tropical fruits

The effect of ozone treatment on total phenol, flavonoid, and vitamin C content of fresh-cut honey pineapple, banana ‘pisang mas’, and guava was investigated. The fresh-cut fruits were exposed to ozone at a flow rate of 8 ± 0.2 ml/s for 0, 10, 20, and 30 min. The antioxidant capacity of the fruits was evaluated by measuring the ferric reducing/antioxidant power (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging activity. Total phenol and flavonoid contents of pineapple and banana increased significantly when exposed to ozone for up to 20 min, with a concomitant increase in FRAP and DPPH values. The opposite was observed for guava. Ozone treatment significantly decreased the vitamin C content of all three fruits. The study shows promising results for enhancing antioxidant capacity of some fresh fruits by ozone treatment although the positive effect is compromised by a reduction in vitamin C content.Industrial relevanceThe preservation of antioxidant properties, storage stability and safety is of utmost importance in the minimally processed fresh food industry. Ozone has been looked into as an alternative sanitizing technology in the fresh produce industry. The results of this study indicate that ozone can be used in the minimally processed fresh food industry to enhance the antioxidant status of fresh-cut fruits.     

Modeling and Analysis of Common-Mode Current Propagation in Broadband Power-Line Communication Networks

This paper proposes a new approach to modeling the common-mode (CM) current propagation path of electrical power-line cables for broadband power-line communications (PLC). In this approach, a CM current propagation model for a three-wire power-line cable is developed using the multiconductor transmission-line theory. The model is used to study the electromagnetic-interference radiation mechanism from the PLC network in the frequency range of 1 to 30 MHz. The accuracy of the model is verified through numerical simulations and practical measurements conducted on the actual power-line network. The developed model allows us to predict the CM current in the power-line cable with reasonable accuracy.     

Capability-based virtual cellular manufacturing systems formation in dual-resource constrained settings using Tabu Search

Formation of Virtual Cellular Manufacturing Systems (VCMSs), as one of the main applications of Group Technology (GT), by presentation of unique and shared capability boundaries of machine tools through defining Resource Elements (REs) creates a good solution for Capability-Based VCMSs (CBVCMSs), which increases opportunities to create systems with more efficient utilizations. Considering workers as the second important resources in Dual-Resource Constraint (DRC) settings makes this problem more serious and critical to research because, in reality, jobs cannot be processed if workers, machines, or both are not available. This paper attempts to form CBVCMSs with DRC settings using a multi-objective mathematical model with a Goal Programming (GP) approach. Using the developed model, parts, machines, and workers are grouped and assigned to the generated virtual cells at the same time. The proposed model is solved through a multi-objective Tabu Search (TS) algorithm to find optimum or near-to-optimum solutions. The validity of the developed model is illustrated by two numerical examples taken from the literature and evaluated through comparing the performance of the CBVCMSs and the original classical CMSs in the System Capacity Utilization (SCU) point of view.     

Radio-frequency common-mode noise propagation model for power-line cable

Electromagnetic-interference (EMI) radiation from a power-line communications (PLC) network has been a major concern for the widespread use of broadband PLC technology. It is also well known that the dominant radiation mode of the PLC network is common mode (CM) by nature. Therefore, for electromagnetic-compatibility planning purposes, knowledge of the CM noise propagation path of the power line in the frequency range of 1 to 30 MHz is essential to provide insight of EMI radiation emitted by the power line. Based on a two-current-probe measurement approach, the CM noise propagation model for a three-wire power-line cable can be derived and represented by an equivalent two-wire CM transmission line. The equivalent CM noise propagation model allows us to predict the CM noise current on the power line with reasonable accuracy. The model will serve as a valuable tool in the future to identify effective ways to suppress EMI radiation from the PLC network.