Dielectric Resonator Antenna Loaded with Reconfigurable Plasma Metamaterial Polarization Converter

In this paper, a plasma based metamaterial (MM) polarizer is optimized for linear to circular polarization conversion in Ku-band wireless applications. The plasma MM polarizer is design based on the transmission mode. The proposed plasma MM polarizer unit-cell element consists of back-to-back plasma arcs placed on the top and the bottom faces of a dielectric substrate. Polarization Conversion from linear polarized (LP) wave to circular polarized (CP) wave requires that the incident wave is splitted into two orthogonal components with equal magnitudes and π/2 phase difference. The polarization characteristics of the plasma MM polarizer have bandwidth of 17.5% centered around 13.7 GHz. A linearly polarized dielectric resonator antenna (DRA) is designed with impedance bandwidth of 27.05%. The LP-DRA loaded with plasma MM polarizer radiates CP-waves with improved gain of 8.89 dBi. Reconfigurable CP radiation right-hand, left-hand, or linear polarization is achieved when the argon gas in the lower, upper, or both arc-shaped containers is ionized to plasma state. The proposed plasma MM polarizer and the DRA structures are examined utilizing a full-wave simulator.

     

Residual Pattern and Dietary Intake of Iprodione on Grapes under Egyptian Field Conditions: A Prelude to Risk Assessment Profile

Field experiments were conducted in two different locations in the Nile delta to determine the residue levels and dissipation rates of iprodione in grapes. Iprodione was applied in different rates (recommended dose and two times recommended dose) and spraying times. Analysis was carried out using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The dissipation rates of iprodione were described using first-order kinetics and the half-life ranged from 8.8 to 9.4 days. There was a sharp decrease in the amount of iprodione residues 10 days after application. At harvest time, the remaining residues of iprodione were below the Food and Agriculture Organization (FAO)/World Health Organization (WHO) maximum residue level (MRL) of 10 mg/kg when measured 14 days after final application. The exposure to iprodione was assessed and compared to acceptable daily intake (ADI). Based on grape consumption, the estimated daily intakes of iprodione ranged from 0.2% to 1.1% of the ADI, showing insignificant risk to consumers.     

Polarization-Independent Reconfigurable Graphene Gas Sensor Using Crescent Plasmonic Antenna

Plasmonics - A polarization-independent gas sensor based on crescent plasmonic dipole antenna loaded with graphene monolayer is introduced in this paper for environment...     

RCS Reduction from Conformal Surfaces Using Plasma-Based AMC Arrays

Plasmonics - Military applications employ metallic objects with different shapes, which must produce low radar cross-section (RCS) to avoid detection and destruction from explosive devices. A...     

Electronic Beam-Scanning Strip-Coded Graphene Leaky-Wave Antenna Using Single Structure

Plasmonics - In this paper, a reconfigurable graphene leaky-wave antenna (GLWA) with electronic beam scanning capability for THz communications system is proposed. It consists of graphene strips...     

Health Hazard Assessment of Pyridaben Residues in Egyptian Strawberries

Dissipation behavior and hazard assessment of the insecticide/acaricide pyridaben applied to strawberries were investigated under the climatic conditions of Egypt. A validated gas chromatographic method (GC-μECD) was used to determine pyridaben residues when applied at the recommended rate and twice this rate. The average recoveries were in the range between 95.8% and 103% with associated relative standard deviation not exceeding 14.5%. The estimated limit of quantification for pyridaben was 0.005 mg/kg. The field results showed that pyridaben dissipated rapidly in strawberries and had a half-life of approximately 2.3 days. The hazard assessment was evaluated by using the hazard quotient (HQ). The results showed that the HQ value was significantly less than HQ = 1. This result implied that the hazard of pyridaben use in strawberries even at double the recommended dosage was negligible to human. This study could provide guidance for the safe and reasonable use of pyridaben in strawberries and to prevent health problems to consumers; however, further hazard assessment studies are needed to ascertain the hazard of pyridaben residues on strawberries to vulnerable groups, including children, pregnant women, and elderly consumers.