Implementation of defected ground structure for microstrip filtenna design

A microstrip patch filtenna inspired by defected ground structure (DGS) is presented in this article. It uses modified split ring resonator and capacitance loaded strip as a radiating element. The presented structure is incorporated with a pair of double U‐shaped DGS (DU‐DGS) to obtain filtering characteristics. The width of DU‐DGS plays a vital role in selecting attenuation poles of the filter as well as for the filtenna circuit. The separation distance between the DU‐DGS also affects the resonant frequency of the structure. Both radiation and filtration can be performed through a single structure, otherwise known as filtenna. The physical size of the proposed filtenna in terms of guided wavelength is 2.465λ_g × 1.160λ_g × 0.116λ_g at 10.8 GHz, and is comparatively less to others reported, so is considered as a superior feature. The presented filtenna possesses impedance bandwidth of 700 and 1800 MHz at 10.8 and 16.6 GHz, which covers standards of X‐ and Ku‐band, respectively. So, this can be referred to as dual band filtenna. The radiation pattern shows omnidirectionality in both E and H planes at resonance.     

High Mobility 3D Dirac Semimetal (Cd3As2) for Ultrafast Photoactive Terahertz Photonics

The Dirac semimetal cadmium arsenide (Cd₃As₂), a 3D electronic analog of graphene, has sparked renewed research interests for its novel topological phases and excellent optoelectronic properties. The gapless nature of its 3D electronic band facilitates strong optical nonlinearity and supports Dirac plasmons that are of particular interest to realize high-performance electronic and photonic devices at terahertz (1 THz = 4.1 meV) frequencies, where the performance of most dynamic materials are limited by the tradeoff between power-efficiency and switching speed. Here, all-optical, low-power, ultrafast broadband modulation of terahertz waves using an ultrathin film (100 nm, λ/3000) of Cd₃As₂ are experimentally demonstrated through active tailoring of the photoconductivity. The measurements reveal the photosensitive metallic behavior of Cd₃As₂ with high terahertz electron mobility of 7200 cm² (Vs)⁻¹. In addition, optical fluence dependent ultrafast charge carrier relaxation (15.5 ps), terahertz mobility, and long momentum scattering time (157 fs) comparable to superconductors that invoke kinetic inductance at terahertz frequencies are demonstrated. These remarkable properties of 3D Dirac topological semimetal envision a new class of power-efficient, high speed, compact, tunable electronic, and photonic devices.     

Nonlinear THz-Nano Metasurfaces

Extreme terahertz (THz) science and technologies, the next disruptive frontier in nonlinear optics, provide multifaceted capabilities for exploring strong light-matter interactions in a variety of physical systems. However, current techniques involve the need for an extremely high-field free space THz source that is difficult to generate and has limited investigations to a rather weak and linear regime of light-matter interactions. Therefore, new approaches are being sought for the tight confinement of THz waves that can induce nonlinear effects. Here, a nonlinear “tera-nano” metasurface is demonstrated exhibiting extremely large THz nonlinearity and sensitive self-modulation of resonances at moderate incident THz field strengths. A record deep-subwavelength (≈λ/33 000) confinement of strongly enhanced (^≈3200) THz field in a nano-gap (15 nm) exhibits remarkable THz field-tailored nonlinearity. Further, ultrafast injection of photocarriers reveals a competition between nonlinear THz field-induced intervalley scattering and optically driven interband excitations. The results on “tera-nano” metasurfaces enable a novel platform to realize enhanced nonlinear nano/micro composites for field-sensitive extreme THz nonlinear applications without the need for intense THz light sources.     

A deep learning based approach to detect IDC in histopathology images

Multimedia Tools and Applications - Breast cancer is one of the widespread reasons of morbidity worldwide that begins in the cells of the tissues of morbidity worldwide in the woman community....     

Fire Controlling Under Uncertainty in Urban Region Using Smart Vehicular Ad hoc Network

Every year thousands of urban and industrial fires occur, which leads to the destruction of infrastructure, buildings, and loss of lives. One of the reasons behind this is the delayed transmission of information to the fire station and the nearer hospitals for ambulance service as the transmission of information is dependent on observer at the location where the fire is caught and cellular network. This paper proposed an automated routing protocol for the urban vehicular ad-hoc network to send the information from the location where the fire is caught to the nearest fire stations and hospitals with optimum service time. This transmission of information involves Road Side Unit (RSU) at the junction and the vehicles present in the transmission path. Selection of route to transmit faulty vehicle information from the RSU to the required faulty vehicle is based on a parameter called path value. The computation of path value is done by the attributes such as expected End To End (E2E) delay, the shortest distance to destination, the density of vehicle between the junctions, and attenuation. From the current junction, the selection of the next junction is based on minimum path value. The proposed routing protocol considers the performance parameters such as E2E delay, total service time (TST), number of network fragments or network gaps, number of hops, and attenuation for the propagation path for the evaluation of the proposed methodology. The proposed routing algorithm is implemented through OmNet++ and SUMO. Results obtained for the proposed routing protocol is compared with three existing VANET protocols (GSR, A-STAR, and ARP) in terms of End To End delay, number of hops, number of vehicular gaps, and Total Service Time (TST).

     

Rendezvous based routing protocol for wireless sensor networks with mobile sink

In wireless sensor networks, the sensor nodes find the route towards the sink to transmit data. Data transmission happens either directly to the sink node or through the intermediate nodes. As the sensor node has limited energy, it is very important to develop efficient routing technique to prolong network life time. In this paper we proposed rendezvous-based routing protocol, which creates a rendezvous region in the middle of the network and constructs a tree within that region. There are two different modes of data transmission in the proposed protocol. In Method 1, the tree is directed towards the sink and the source node transmits the data to the sink via this tree, whereas in Method 2, the sink transmits its location to the tree, and the source node gets the sink’s location from the tree and transmits the data directly to the sink. The proposed protocol is validated through experiment and compared with the existing protocols using some metrics such as packet delivery ratio, energy consumption, end-to-end latency, network life time.     

PSO-DS: a scheduling engine for scientific workflow managers

Cloud computing, an important source of computing power for the scientific community, requires enhanced tools for an efficient use of resources. Current solutions for workflows execution lack frameworks to deeply analyze applications and consider realistic execution times as well as computation costs. In this study, we propose cloud user–provider affiliation (CUPA) to guide workflow’s owners in identifying the required tools to have his/her application running. Additionally, we develop PSO-DS, a specialized scheduling algorithm based on particle swarm optimization. CUPA encompasses the interaction of cloud resources, workflow manager system and scheduling algorithm. Its featured scheduler PSO-DS is capable of converging strategic tasks distribution among resources to efficiently optimize makespan and monetary cost. We compared PSO-DS performance against four well-known scientific workflow schedulers. In a test bed based on VMware vSphere, schedulers mapped five up-to-date benchmarks representing different scientific areas. PSO-DS proved its efficiency by reducing makespan and monetary cost of tested workflows by 75 and 78%, respectively, when compared with other algorithms. CUPA, with the featured PSO-DS, opens the path to develop a full system in which scientific cloud users can run their computationally expensive experiments.     

Estimation of critical dimensions for a trapezoidal-shaped steel fin using hybrid differential evolution algorithm

This paper deals with the inverse prediction of parameters in a trapezoidal fin with temperature-dependent thermal conductivity and heat transfer coefficient. Three critical dimensions along with the relevant heat transfer coefficient at the fin base have been simultaneously predicted for satisfying a given temperature distribution on the surface of the trapezoidal fin. The inverse problem is solved by a hybrid differential evolution-nonlinear programming (DE-NLP) optimization method. For a given fin material which is considered to be stainless steel, it is found from the present study that many feasible dimensions exist which satisfy a given temperature distribution, thereby providing flexibility in selecting any dimensions from the available alternatives by appropriately regulating the base heat transfer coefficient. A very good estimation of the unknown parameters has been obtained even for temperature distribution involving random measurement errors which is confirmed by the comparisons of the reconstructed distributions. It is concluded that for a given fin material, the hybrid DE-NLP algorithm satisfactorily estimates feasible dimensions of a trapezoidal fin even with random measurement error of 11 %.

     

Hedgehog Antagonist Pyrimidine–Indole Hybrid Molecule Inhibits Ciliogenesis through Microtubule Destabilisation

One of the crucial regulators of embryonic patterning and tissue development is the Hedgehog‐glioma (Hh‐Gli) signalling pathway; its uncontrolled activation has been implicated in different types of cancer in adult tissues. Primary cilium is one of the important factors required for the activation of Hh signalling, as it brings the critical components together for key protein–protein interactions required for Hh pathway regulation. Most of the synthetic and natural small molecule modulators of the pathway primarily antagonise Smoothened (Smo) or other effectors like Hh ligand or Gli. Here, we report a previously described Hh antagonist, with a pyrimidine–indole hybrid (PIH) core structure, as an inhibitor of ciliogenesis. The compound is unique in its mode of action, as it shows perturbation of microtubule dynamics in both cell‐based assays and in vivo systems (zebrafish embryos). Further studies revealed that the probable targets are α‐tubulin and its acetylated form, found in the cytoplasm and primary cilia. PIH also showed axonal defasiculation in developing zebrafish embryos. We thus propose that PIH antagonises Hh signalling by repressing cilia biogenesis and disassembling α‐tubulin from its stabilised form.     

Flexible and free-standing films containing cobalt-doped nanocrystalline zinc oxide dispersed in polyvinylidene fluoride matrix: synthesis and characterization

Polymer Bulletin - Synthesis of free-standing flexible Co-ZnO/PVDF composite films is realized by sol–gel technique. Modulation of the optical and microstructural properties of the above...