Performance Analysis of a Cognitive Radio Network Under Energy Harvesting from Primary User Emulation Attacker

Wireless Personal Communications - The paper reports the performance of an energy harvesting cognitive radio network under primary user emulation (PUE) attack. A secondary user (SU) can harvest...     

Investigation on effects of system parameters on transmission depth in underwater wireless optical communication

Photonic Network Communications - Performance of underwater wireless optical communication (UWOC) with different vertical water channel conditions is experimentally analyzed. Experiment has been...     

Microstructure induced ultra-high energy storage density coupled with rapid discharge properties in lead-free Ba0.9Ca0.1Ti0.9Zr0.1O3–SrNb2O6 ceramics

Novel lead-free (1-x)Ba_0·9Ca_0·1Ti_0·9Zr_0·1O₃-xSrNb₂O₆ ceramics were synthesized via a two-step high energy ball milling process. The evolution of microstructural properties, phase transformation, and energy storage characteristics was comprehensively investigated to assess the applicability of material in multi-layered ceramic capacitors. The substitution of SrNb₂O₆ (SNO) in Ba_0·9Ca_0·1Ti_0·9Zr_0·1O₃ (BTCZ) has resulted in substantial improvement in materials density along with a small increase in the grain size of the synthesized ceramic. A thorough microstructural investigation indicates an excellent dispersibility and compatibility between BTCZ and SNO phases. With an increase in SNO substitution, a transition from typical ferroelectric to relaxor ferroelectric has been observed, which has led to a significantly slimmer ferroelectric loop along with frequency dispersive dielectric properties. The optimized composition (i.e., x = 0.10) exhibits an ultra-high recoverable energy density of 2.68 J/cm³ along with a moderately high energy efficiency of 83.4%. Further, SNO substituted samples have also shown an enhancement in breakdown strength. The improvement in energy storage performance and breakdown strength of SNO substituted BTCZ composites are mainly attributed to relatively homogeneous grain morphology, optimum grain size, microstructural density, and improved grain boundary interface.     

Computer‐aided design methodology for linearity enhancement of multiwatt GaN HEMT amplifiers using multiple parallel devices

This article presents a design methodology for linearizing GaN HEMT amplifiers based on splitting a large FET into multiple parallel FETs with same total gate periphery and by biasing them individually. By varying the biases, the magnitude and the phase of the IMD3 components at the output of FET changes. A detailed simulation methodology using commercial microwave CAD software is presented. Simulation results show that by biasing one device in Class AB and other(s) in deep Class AB mode, IMD3 components of parallel FETs can be made out of phase to each other leading to cancellation and improvement in linearity. Three prototype circuits were simulated using (a) a single 5 mm FET (1 × 5 mm), (b) two parallel 2.5 mm FETs (2 × 2.5 mm), and (c) four parallel 1.25 mm FETs (4 × 1.25 mm), for a total gate periphery of 5 mm, over the frequency range of 0.8 to 1.0 GHz. IMD3 improvement up to 20 dBc was achieved with the 4 × 1.25 mm circuit when the FET biases were optimized. Measurement results show improvement in linearity up to 20 dBc for 4 × 1.25 mm circuit. The proposed method improves linearity without a substantial penalty on the power consumption and is straightforward to implement.     

A Dynamic Inertial Weight Strategy in Micro PSO for Swarm Robots

Wireless Personal Communications - A relatively new area of research and development is Swarm Robotics. It is a part of the swarm intelligence field. In the proposed paper, we shall use swarm...     

Cross-Layer Energy Based Clustering Technique for Heterogeneous Wireless Sensor Networks

Wireless Personal Communications - Effect of combination of dual split ring resonator and electromagnetic bandgap structures over substrate integrated waveguide and half-mode substrate integrated...     

Study of physicochemical properties of flutamide-loaded Ocimum basilicum microspheres with ex vivo mucoadhesion and in vitro drug release

Drug which shows extensive first pass effect is difficult task that, needs to be solved by formulators in the pharmaceutical science. The low oral bioavailability (49%) of flutamide may be due to poor wettability, low aqueous solubility and extensive first pass effect. The aim of present investigation was to prepare flutamide loaded microspheres and incorporate it into suppositories for rectal delivery to avoid first pass effect and enhance residence time. Flutamide loaded mucoadhesive microspheres of Ocimum Basilicum mucilage (OBM) were prepared using spray drying and characterized by percent production yield, encapsulation efficiency, particle size, zeta potential, polydispersity index, DSC, SEM, XRPD, in vitro drug release and stability studies. Moreover, ex vivo mucoadhesion was investigated using falling liquid film technique to determine the adhesion of microspheres to sheep rectal mucosa. The microspheres had nearly spherical shape and size about 2.53?μm. The encapsulation efficiency and mucoadhesion of optimized formulation MBF10 were found to be 69.6?±?2.3% and 89.01?±?2.18%, respectively. Percent CDR of optimized flutamide loaded mucoadhesive microspheres was found to be 88.7?±?1.3 at 7?h. In conclusion, OBM microparticles based suppository could be used to deliver drug through rectal delivery.     

Mammalian-Cell-Driven Polymerisation of Pyrrole

A model cancer cell line was used to initiate polymerisation of pyrrole to form the conducting material polypyrrole. The polymerisation was shown to occur through the action of cytosolic exudates rather than that of the membrane redox sites that normally control the oxidation state of iron as ferricyanide or ferrocyanide. The data demonstrate for the first time that mammalian cells can be used to initiate synthesis of conducting polymers and suggest a possible route to detection of cell damage and/or transcellular processes through in situ and amplifiable signal generation.     

Thermal-aware task allocation and scheduling for periodic real-time applications in mesh-based heterogeneous NoCs

Real-Time Systems - With continuous technology scaling, the power density and hence the temperature of Network-on-Chip (NoC) may increase rapidly. This in-turn degrades the performance of the chip...     

Comparison between the use of thermoplasticized gutta‐percha and a polydimethyl siloxane‐based material in filling internal resorptive cavities using spiral computed tomography

To evaluate the fill of internal resorption cavities obturated with thermoplasticized gutta‐percha and GuttaFlow2 using CT scan. Twenty human maxillary anterior teeth were selected and root canals were prepared using ProTaper system to size F3. Irrigation was performed with 5 ml of 2.5% sodium hypochlorite (NaOCl) and 5 ml of 17% ethylenediaminetetraacetic acid (EDTA). Each root was then sectioned horizontally into two halves and semicircular cavities were prepared around the periphery of the root canal opening of each root half, using a round bur. Both the root halves were then fixed using cyanoacrylate glue. All the specimens were subjected to preoperative CT scan analysis to determine the volume of internal cavities. The samples were then randomly divided into two groups. In Group 1, the specimens were obturated with thermoplasticized gutta‐percha (E&Q system) and specimens in Group 2 were obturated using GuttaFlow2. All specimens were then subjected to postoperative CT scan analysis. The volume of voids in internal resorptive cavities were calculated, which was then used to estimate the amount of gutta‐percha filled. There was no significant difference in volume of internal resorptive cavities between thermoplasticized gutta‐percha and GuttaFlow2 groups before obturation (p = 0.466). However, after obturation there was a significant difference between both the groups, in which GuttaFlow2 demonstrated better fill (p = .014). Thermoplasticized gutta‐percha filled 81% of internal resorptive cavity while GuttaFlow2 filled 91%, respectively. GuttaFlow2 showed better fill than thermoplasticized gutta‐percha in the filling of internal resorptive cavities.