Ultrasound enhanced 50 Hz plasma treatment of glass-fiber-reinforced polyester at atmospheric pressure

Glass-fiber-reinforced polyester (GFRP) plates are treated using a 50?Hz dielectric barrier discharge at a peak-to-peak voltage of 30?kV in helium at atmospheric pressure with and without ultrasonic irradiation to study adhesion improvement. The ultrasonic waves at the fundamental frequency of around 30?kHz with the sound pressure level of approximately 155?dB were introduced vertically to the GFRP surface through a cylindrical waveguide. The polar component of the surface energy was almost unchanged after the plasma treatment without ultrasonic irradiation, but drastically increased approximately from 20 up to 80?mJ?m^?2 with ultrasonic irradiation. The plasma treatment with ultrasonic irradiation also introduced oxygen- and nitrogen-containing functional groups at the GFRP surface. These changes would improve the adhesion properties of the GFRP plates.     

Nanograins dependent dielectric constant, tunability, phase transition, impedance spectroscopy and leakage current of (Pb1 − xSrx)TiO3 thin films

Nanostructured (Pb_1 − xSr_x)TiO₃ (PST) (x = 0.1, 0.2 and 0.3) thin films have been prepared by chemical solution deposition process using spin coating technique. The solution as such was deposited on Pt/Ti/SiO₂/Si substrates and annealed at 650 °C/3h. Nanograins dependent dielectric properties of PST films show dielectric constant up to the higher frequency region, low losses, large tunability and phase transition at small temperature. The impedance data has been fitted by Cole-Cole model to study the effect of grain boundaries on the dielectric properties. The current-voltage characteristics have been measured to study leakage current in PST films and described by Poole-Frenkel emission model. It is suggested that the key carrier transport process in PST films is emission of electrons from a trap state near the metal-film interface into a continuum of states associated with each conductive dislocation. The activation energy value for carrier transport in PST films is obtained from temperature-dependent current-voltage characteristics.     

Design and Synthesis of Dihydroxamic Acids as HDAC6/8/10 Inhibitors

We report the synthesis and evaluation of a class of selective multitarget agents for the inhibition of HDAC6, HDAC8, and HDAC10. The concept for this study grew out of a structural analysis of the two selective inhibitors Tubastatin A (HDAC6/10) and PCI-34051 (HDAC8), which we recognized share the same N-benzylindole core. Hybridization of the two inhibitor structures resulted in dihydroxamic acids with benzyl-indole and -indazole core motifs. These substances exhibit potent activity against HDAC6, HDAC8, and HDAC10, while retaining selectivity over HDAC1, HDAC2, and HDAC3. The best substance inhibited the viability of the SK-N-BE(2)C neuroblastoma cell line with an IC₅₀ value similar to a combination treatment with Tubastatin A and PCI-34051. This compound class establishes a proof of concept for such hybrid molecules and could serve as a starting point for the further development of enhanced HDAC6/8/10 inhibitors.     

Throughput of cognitive radio networks with improved energy detector under security threats

Spectrum sensing in cognitive radio networks (CRNs) is subjected to some security threats such as primary user emulation (PUE) attack and spectrum sensing data falsification (SSDF) attack. In PUE attack, a malicious user (MU_PUE) transmits an emulated primary signal throughout the spectrum sensing interval to secondary users (SUs) to forestall them from accessing the primary user (PU) spectrum bands. In SSDF attack, malicious users (MU_SSDF) intentionally report false sensing decisions to the fusion center (FC) to influence the overall decision. While most of the existing literatures have studied the effects of these 2 types of attacks separately, the present paper evaluates the secondary network performance in terms of throughput under both the PUE and SSDF attacks with improved energy detectors (IEDs) where SU's spectrum access is hybrid, ie, either in overlay or in underlay mode. An analytical expression on throughput of SU under the simultaneous influence of both of these attacks is developed. Impact of several parameters such as IED parameter, attacker probabilities, and attacker strength on the throughput of SU is investigated. Performance of the present scheme is also compared with only PUE and only SSDF attacks. A simulation test bed is developed in MATLAB to validate our analytical results.     

A fuzzy‐based trust model for flying ad hoc networks (FANETs)

The use of unmanned aerial vehicles has significantly increased for forming an ad hoc network owing to their ability to perform in exciting environment such as armed attacks, border surveillance, disaster management, rescue operation, and transportation. Such types of ad hoc networks are popularly known as flying ad hoc networks (FANETs). The FANET nodes have 2 prominent characteristics—collaboration and cooperation. Trust plays an important role in predicting the behavior of such nodes. Researchers have proposed various methods (direct and indirect) for calculation of the trust value of a given node in ad hoc networks, especially in mobile ad hoc networks and vehicular ad hoc networks. The major characteristic that differentiates a FANET from other ad hoc networks is the velocity of the node; as a result, there are frequent losses in connection and topology change. Therefore, the existing methods of trust calculation are not efficient and effective. In this paper, a fuzzy‐based novel trust model has been proposed to handle the behavioral uncertainty of FANET nodes. Nodes are classified using a multicriteria fuzzy classification method based on node's behavior and performance in the fuzzy and complex environment. Quality of service and social parameter (recommendation) are considered for evaluating the trust value of each node to segregate the selfish and malicious nodes. With the node classification, FANET nodes are rewarded or punished to transform node behavior into a trust value. Compared with the existing trust techniques, the simulation results show that the proposed model has better adaptability, accuracy, and performance in FANETs.     

Response of pearl-millet to zinc fertilization in relation to DTPA extractable zinc

The response of pearl-millet (Pennisetum americanum) grown on forty eight diverse soils to applied zinc fertilization was examined in a screenhouse experiment. The DTPA-extractable soil zinc ranged from 0.34 to 1.42 mg kg^–1. In many of the soils yield was increased by the addition of zinc and there were large differences in the size of the response. The critical level of zinc in soil and plant — below which response to applied zinc may be expected — was determined by a graphical method. The values found were 0.65 and 18 mg kg^–1, respectively. Bray's percent yield was positively and significantly related with both soil Zn (r = 0.88) and plant Zn (r = 0.72).     

Response of chickpea (Cicer arietinum) to zinc fertilization and its critical level in soils of semi-arid tropics

In a greenhouse experiment the response of chickpea (Cicer arietinum) to zinc fertilization was examined using 27 soils from the semi-arid tropics. The critical level of DTPA extractable soil Zn was evaluated. Zinc additions to the soil increased the dry matter yield of six weeks old plant shoot, grain and straw significantly at the 5 mg kg^–1 level, but tended to decrease it at the 10 mg kg^–1 level.The DTPA extractable Zn of the soils ranged from 0.28 to 1.75 ppm and was negatively correlated at 1 per cent level with pH (r = – 0.81) and positively with organic carbon (r = 0.79) and Olsen's P (r = 0.63). The per cent yield increase or decrease over zero zinc ranged from 67 to – 16 in respect of grain yield and was positively correlated with available Zn (r = 0.86^**). Zinc concentration in plants was greatly increased with the application of Zn and accumulation of Zn was higher in grain than straw. The critical level of available zinc in soil below which plant response to Zn fertilization may be expected was 0.48 mg Zn kg^–1 soil. Soils between 0.48 to 0.70 mg kg^–1 of DTPA extractable Zn appear boarderline and a negative response to applied Zn was observed in soils of high Zn category. The results show the suitability of DTPA soil test for demarcating soils on the basis of plant response to zinc fertilization.