Broadband simultaneously RHCP‐LHCP radiating microstrip fed rectangular slot antenna for polarization diversity applications

In this article, for the first time, an antenna that can radiate LHCP and RHCP waves simultaneously is presented. The antenna enables simultaneous transmission of both right‐handed (RH) and left‐handed (LH) circular polarized (CP) waves separately over an elevation range from ?45 ^° to ?5 ^° and 5 ^° to 45 ^° from the zenith. The simultaneous radiation of dual sense CP in the different spatial directions enables the antenna to act as polarization diversity transmitter. The mechanism of virtual sequential rotation of magnetic currents inside the different parts of the slot, excited with uniform phase fields results in dual CP generation. The uniform phase orthogonal fields are generated in the different parts of the slot essentially by exciting the full wavelength rectangular slot loaded with grounded stubs, symmetrically, with a shorted microstrip line. The final design of the slot antenna arrived with a rigorous parametric study on different dimensional parameters of slot and grounded stub. The measured impedance bandwidth of 22.5% centered around 7 GHz and axial ratio bandwidth of 19% is achieved. An overlapping bandwidth of 17% is achieved where both matching and AR are very good. The measured isolation between the RHCP and LHCP in the above‐mentioned elevation ranges is maintained above 10 dB. The simulated and experimental results are matching very well.     

Performance analysis of image steganography using wavelet transform for safe and secured transaction

Multimedia Tools and Applications - Internet applications are increased and growing at efficient way. By this technological growth, data communication in the internet in secured way has got a...     

New methodology for light weight solutions to improve BIW structural performance using bulk head optimization

Body-in-white (BIW) is the Car body with welded sheet metal parts painted in white. Automobile companies were trying to optimize mass and improve performance with optimal mass addition. In many automotive industries many BIW designs due to aggressive mass optimization, there is a need to have smart solutions to improve BIW structure performance with very little mass increase. In this paper, a new technique of identifying the optimized internal reinforcements in the BIW at conceptual BIW design phase using Deign of experiments and Multi-objective optimization has been investigated. The paper focus on the Bending and torsion stiffness load cases to evaluate the BIW performance. Bulk head designs were designed at the major joints like A-pillar, B-pillar, C-pillar and rocker and their optimal locations to improve stiffness with minimum mass increase were identified using Design of experiments and multi objective techniques. The research shows that the optimized Bulk head design locations using the DOE technique has improved the overall BIW stiffness performance by 3.9% with 1.2% of mass addition in the BIW.     

Low Area FPGA Implementation of AES Architecture with EPRNG for IoT Application

Journal of Electronic Testing - Nowadays, the Internet of Things (IoT) is widely used in the daily lives of humans, which range from tiny wearable devices to huge industrial systems. However,...     

Obstructive sleep apnea in incremental hemodialysis: Determinants,consequences, and impact on survival

Sleep disorders are common in hemodialysis patients, although causes and consequences remain unclear. We sought to establish prevalence, determinants, and outcomes of sleep disturbances in patients receiving incremental dialysis. One hundred two unselected patients undergoing incremental high‐flux hemodialysis or hemodiafiltration underwent limited overnight sleep study. Large subsets underwent echocardiography, interdialytic ambulatory blood pressure monitoring, and brain natriuretic peptide measurements. Patients were followed up to 44 months. Full sleep data were obtained in 91 patients. All had sleep disturbance as evidenced by an apnea–hypopnea index >5/min. We defined major obstructive sleep apnea (MOSA) as an apnea–hypopnea index ≥15, together with either significant oxygen desaturation or symptoms of daytime sleepiness. Forty patients met these criteria. Significant independent predictors of MOSA were age <65 years, male gender, has diabetes, and has a brain natriuretic peptide >2500 pg/mL. Mean ambulatory blood pressure and left ventricular mass index were significantly higher in these patients. In a model controlling for body mass index, high C‐reactive protein, and the presence of cancer, MOSA was associated with a twofold increased risk of mortality, although this did not reach statistical significance. MOSA was common, and was associated with hypertension and high left ventricular mass index. Whether obstructive sleep apnea contributes to the high mortality remains to be firmly established.     

Gold nanoparticle–polypyrrole composite modified TiO<Subscript>2</Subscript> nanotube array electrode for the amperometric sensing of ascorbic acid

Titanium dioxide (TiO₂) nanotubes were fabricated by anodisation of titanium foil in 0.15 M ammonium fluoride in an aqueous solution of glycerol (90 % v/v). Electropolymerisation of pyrrole and deposition of gold nanoparticles on to the TiO₂ nanotube array electrode were carried out by cyclic voltammetry (CV). Electrochemical characterization of the sensor was performed by CV and electrochemical impedance spectroscopy. The morphology of the electrode was studied after every step of modification using field emission scanning electron microscope and atomic force microscope. The sensor was tested for AA and other biomolecules in phosphate buffered saline solution of pH 7 using CV, differential pulse voltammetry and amperometry. The sensor exhibited very high sensitivity of 63.912 μA mM^?1 cm^?2 and excellent selectivity to ascorbic acid (AA) in the presence of other biomolecules such as uric acid, dopamine, glucose and para-acetaminophen. It also showed very good linearity (R = 0.9995) over a wide range (1 μM–5 mM) of detection. The sensor was tested for AA in lemon and found its concentration to be 339 mg ml^?1.     

Challenges in hydrogen fuel sampling due to contaminant behaviour in different gas cylinders

Increasing deployment of fuel cell electric vehicles (FCEVs) has led to implementation of hydrogen quality regulations (ISO 14687:2019) to prevent FCEV loss of performance. Hydrogen refuelling stations operators must be able to send representative samples of hydrogen fuel for analysis. Stability of contaminants in sampling vessels needs to be known at ISO 14687:2019 thresholds. A 4-month stability study was carried out on mixtures of ISO 14687 contaminants at amount fractions close to the thresholds in two types of sampling cylinders (SPECTRA-SEAL® and SGS? aluminium cylinders). SPECTRA-SEAL® cylinder allowed representative sampling of CO, CO₂, CH₄, C₂H₆, N₂, Ar, He, Cl₂CH₂, H₂O, O₂, CH₂O₂ in hydrogen fuel for 2 months. SGS? cylinder allowed representative sampling of CO, CO₂, CH4, C₂H₆, N₂, Ar, He, Cl₂CH₂, H₂O, O₂, H₂S for 4 months. Further work is needed to allow representative sampling of ammonia and formaldehyde.