A framework for implementation of RVE‐based multiscale models in computational homogenization using isogeometric analysis

This study presents an isogeometric framework for incorporating representative volume element–based multiscale models into computational homogenization. First‐order finite deformation homogenization theory is derived within the framework of the method of multiscale virtual power, and Lagrange multipliers are used to illustrate the effects of considering different kinematical constraints. Using a Lagrange multiplier approach in the numerical implementation of the discrete system naturally leads to a consolidated treatment of the commonly employed representative volume element boundary conditions. Implementation of finite deformation computational strain‐driven, stress‐driven, and mixed homogenization is detailed in the context of isogeometric analysis (IGA), and performance is compared to standard finite element analysis. As finite deformations are considered, a numerical multiscale stability analysis procedure is also detailed for use with IGA. Unique implementation aspects that arise when computational homogenization is performed using IGA are discussed, and the developed framework is applied to a complex curved microstructure representing an architectured material.     

Offset‐fed trapezoidal monopole antenna for broadband circular polarization

A novel broadband circularly polarized monopole antenna consisting of an isosceles trapezoidal monopole antenna which is offset fed by a microstrip line is presented. By choosing an appropriate offset, it is possible to establish two orthogonal current components that are out of phase by 90° and thus producing circular polarization. The axial ratio bandwidth of the proposed antenna has been further increased by adding a vertical slot parallel to the microstrip feed line. The measured results show that the proposed antenna has a 34.57% (1.89 GHz to 2.68 GHz) 3 dB axial ratio bandwidth. The ?10 dB reflection coefficient bandwidth is 122.53% (1.04 GHz to 4.33 GHz). The advantages of the proposed antenna are simplicity and a broad 3 dB axial ratio bandwidth.     

A polarization reconfigurable CPW fed monopole antenna with L‐shaped parasitic element

A coplanar waveguide fed polarization reconfigurable monopole antenna is proposed in this letter. The proposed antenna consists of L‐shaped stubs placed on either side of a monopole, two p‐i‐n diodes and a slot in the ground plane. In the proposed antenna structure, the switching element is not directly connected to the feed line. Depending on the switching state of the p‐i‐n diodes, the antenna either radiates left/right circular polarization or linear polarization. To validate the proposed design, the antenna was fabricated and its performance was measured. Since the ground plane is electrically small, the effect of the cable and SMA connector on the performance of the antenna is also investigated. The measured impedance bandwidth is 66.78% (3.67 GHz to 7.35 GHz) and the axial ratio bandwidth is 13.62% (4.24‐4.86 GHz) for circular polarization and 23.61% (3.81‐4.83 GHz) impedance bandwidth for linear polarization.     

Design of periodic elastoplastic energy dissipating microstructures

The design of periodic elastoplastic microstructures for maximum energy dissipation is carried out using topology optimization. While the topology optimization of elastic microstructures has been performed in numerous studies, microstructural design considering inelastic behavior is relatively untouched due to a number of reasons which are addressed in this study. An RVE-based multiscale model is employed for computational homogenization with periodic boundary constraints, satisfying the Hill-Mandel principle. The plastic anisotropy which may be prevalent in materials fabricated through additive manufacturing processes is considered by modeling the constitutive behavior at the microscale with Hoffman plasticity. Discretization is done using enhanced assumed strain elements to avoid locking from incompressible plastic flow under plane strain conditions and a Lagrange multiplier approach is used to enforce periodic boundary constraints in the discrete system. The design problem is formulated using a density-based parameterization in conjunction with a SIMP-like material interpolation scheme. Attention is devoted to issues such as dependence on initial design and enforcement of microstructural connectivity, and a number of optimized microstructural designs are obtained under different prescribed deformation modes.

     

Trust-Aware Fuzzy Evaluation Method for Preventive Route Generation in Mobile Network

The existence of a non-cooperative or black hole node as an intermediate node in a mobile network can degrade the performance of the network and affects the trust of neighbor nodes. In this paper, a trust-aware routing protocol is defined for improving the routing reliability against black hole attacks. A new Trust aware and fuzzy regulated AODV (TFAODV) protocol is investigated in this work as an improvement over the existing AODV protocol. The session-driven evaluation of stability, communication-delay, and failure-ratio parameters are conducted for evaluating the trust of nodes. The fuzzy rules apply to these parameters for computing the degree of trust. This trust vector isolates the attack-suspected and trustful nodes. The proposed TFAODV protocol used the trustful mobile nodes as the intermediate path nodes. The proposed protocol has been experimented with in the NS2 simulation environment. The analytical results are obtained in terms of PDR ratio, Packet Communication, Loss rate parameters. The comparative results are derived against the AODV, Probabilistic AODV, PDS-AODV, PSAODV, and Juneja et al. protocols. The analysis is performed on different scenarios varied in terms of network density, degree of stability, and the number of attackers. The simulation results ensured the proposed TFAODV protocol has improved the PDR ratio and reduced the communication loss significantly against these state-of-art protocols.

     

Modern architecture for photonic networks-on-chip

Development in photonic integrated circuits (PICs) provides a promising solution for on-chip optical computation and communication. PICs provides the best alternative to traditional networks-on-chip (NoC) circuits which face serious challenges such as bandwidth, latency and power consumption. Integrated optics have substantiated the ability to accomplish low-power communication and low-power data processing at ultra-high speeds. In this work, we propose a new architecture for NoC, which might improve overall on-chip network performance by reducing its power consumption, providing large channel capacity for communication, decreasing latency among nodes and reducing hop count. Some of the key features of the proposed architecture are to reduce the waveguide network for communication among nodes, and this architecture can be used as a brick to construct other architectures. In this architecture, we use micro-ring resonator (MRR) and it is used to provide a high bandwidth connection among nodes with a lesser number of waveguide networks. Furthermore, results show that this architecture of PICs provides better performance in terms of low communication latency, low power consumption, high bandwidth. It also provides acceptable FSR value, FWHR value, finesse value and Q-factor of micro-ring resonators used for the design of MRR in this architecture.

     

Entanglement dynamics in two-parameter qubit–qutrit states under Dzyaloshinskii–Moriya interaction

We study entanglement dynamics in two-parameter qubit–qutrit states under the influence of Dzyaloshisnhkii–Moriya (DM) interaction. Our system consists of a qubit–qutrit pair as a closed system initially in two-parameter class of states, and one environmental qubit interacts with the qutrit of the closed system via DM interaction. We divide our analysis into two cases. In the first case, we study the entanglement dynamics in separable region, and in the second case we study the same in non-separable region. The DM interaction produces the entanglement in separable region with entanglement sudden death (ESD) and some states in this region remain unaffected by the same. In non-separable region, all the states are affected by DM interaction. The DM interaction excites the entanglement but does not produce ESD in this region. We observed that probability amplitude of environmental qubit does not affect the entanglement in two-parameter qubit–qutrit states in both the regions.     

Nafion-film-based micro–nanofluidic device for concurrent DNA preconcentration and separation in free solution

This paper presents a Nafion-film-based micro–nanofluidic device for concurrent DNA preconcentration and separation. The principle of the device is based on the combination of (a) ion concentration polarization phenomenon at the junction of the microchannel and the nanochannels in the Nafion film to form opposing electrophoretic and electroosmotic forces acting on the DNAs and (b) end-labeled-free solution electrophoresis to harness the charge-to-mass ratio for molecular differentiation. The experiments successfully demonstrated concurrent preconcentration and separation of DNA mixture in free solution within 240 s, yielding concentration ratios up to 1,150× and separation resolution of 1.85. The effect of applied electric field on the concentration and separation performance was also investigated. The device can be used as a key sample preparation element in conjunction with micro- or nano-fluidic sensors for microTAS functionality.     

Salmonella typhimurium in the Australian egg industry: Multidisciplinary approach to addressing the public health challenge and future directions

In Australia, numerous egg-related human Salmonella typhimurium outbreaks have prompted significant interest among public health authorities and the egg industry to jointly address this human health concern. Nationwide workshops on Salmonella and eggs were conducted in Australia for egg producers and regulatory authorities. State and national regulators represented Primary Production, Communicable Disease Control, Public Health and Food Safety, and Food Standards Australia and New Zealand. All attendees participated in discussions aimed at evaluating current evidence-based information, issues related to quality of egg production, and how to ensure safe eggs in the supply chain, identifying research gaps and practical recommendations. The perceptions from egg producers and regulatory authorities from various states were recorded during the workshops. We presented the issues discussed during the workshops, including Salmonella in the farm environment, Salmonella penetration across eggshell, virulence in humans, food/egg handling in the supply chain, and intervention strategies. We also discussed the perceptions from egg producers and regulators. Recommendations placed emphasis on the future research needs, communication between industry and regulatory authorities, and education of food handlers. Communication between regulators and industry is pivotal to control egg-borne S. typhimurium outbreaks, and collaborative efforts are required to design effective and appropriate control strategies.