A new compact planar UWB monopole antenna

A new compact planar monopole antenna which covers an ultra wide bandwidth of ～147% from 2.96 to 19.43 GHz for S₁₁ ≤ ?10 dB is presented. The proposed antenna has simple configuration and easily fed by using a 50 Ω microstrip line. The total size of the antenna is 30 × 26 × 1.6 mm³. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

Adaptive beamforming algorithm with increased speed and improved reliability for smart antennas

In this paper, a novel adaptive beamforming algorithm has been proposed which can be used for tracking the subscribers of a smart antenna in a wide angle spread environment. It can be adapted for arbitrary variations in both eigenvalues and eigenvectors of the autocorrelation matrix of received signal which is mostly the case for moving subscribers’ environment. Moreover, it uses one adaptive module which is less than two adaptive modules of previous works and leads to a high speed at least two times more than previous works.     

Polycyclic aromatic hydrocarbons in milk and dairy products

Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds with a structure consisting of carbon and hydrogen atoms that have more than two fused aromatic rings. Most PAHs have carcinogenic effects on animal or humans and induce various cancers. Polycyclic aromatic hydrocarbons are a consequence of environmental pollutants, imperfect burning or pyrolysis of organic substances during industrial processing. Additionally, foods can be contaminated during their processing and preparation through different heat treatments. This review highlights the formation, occurrence and health impacts of PAHs in milk and milk products, and analytical technique used for their determination in dairy products.     

Rethink about electrolyte: Potassium fluoride as a promising additive to an electrolyte for the water oxidation by a nanolayered Mn oxide

Water oxidation is a bottleneck of the hydrogen production through the water-splitting reaction. Herein, the promising role of fluoride on the water-oxidizing activity of a nanolayered Mn oxide under the electrochemical condition is reported. The experiments show the increase of the water-oxidizing activity of the nanolayered Mn oxide under an electro-water oxidation circumstance in the presence of potassium fluoride as a promising additive to an electrolyte. As a result, the required overpotential is decreased and the yield of oxygen evolution raised in the water-oxidation reaction.     

Environmental management in Urmia Lake: thresholds approach

Urmia Lake is a vivid example of negligence in providing the environmental water requirement rooted in prolonged droughts and excessive upstream water withdrawal. The aim of this study is to propose a reclamation strategy for the lake by focusing on estimation of environmental requirement thresholds under various drought severity conditions. On the average, the lake will remain in a moderate hydrological drought condition if the business-as-usual scenario prevails. The shares of natural drought, water withdrawals and water resources development projects (i.e. dams) in recent lake inflow reduction are estimated at 45%, 40% and 15%, respectively; thus, the aggregated contribution of human-induced factors has a more significant impact on the current lake condition than that of natural drought, and a firm and consistent approach to reduce water consumption by the agricultural sector is required for lake reclamation.     

A reconfigurable frequency-selective surface for dual-mode multi-band filtering applications

A reconfigurable single-layer frequency-selective surface (FSS) with dual-mode multi-band modes of operation is presented. The proposed structure is printed on a compact 10 × 10 mm² FR4 substrate with the thickness of 1.6 mm. A simple square loop is printed on the front side while another one along with two defected vertical arms is deployed on the backside. To realise the reconfiguration, two pin diodes are embedded on the backside square loop. Suitable insertion of conductive elements along with pin diodes yields in dual-mode multi-band rejection of applicable in service frequency ranges. The first operating mode due to diodes’ ‘ON’ state provides rejection of 2.4 GHz WLAN in 2–3 GHz, 5.2/5.8 GHz WLAN and X band in 5–12 GHz, and a part of Ku band in 13.9–16 GHz. In diodes ‘OFF’ state, the FSS blocks WLAN in 4–7.3 GHz, X band in 8–12.7 GHz as well as part of Ku band in 13.7–16.7 GHz. As well, high attenuation of incident waves is observed by a high shielding effectiveness (SE) in the blocked frequency bands. Also, a stable behaviour against different polarisations and angles of incidence is obtained. Comprehensive studies are conducted on a fabricated prototype to assess its performance from which encouraging results are obtained.     

Physical Properties of Titanium Oxide Thin Films Prepared by DC Magnetron Sputtering: Influence Substrate Temperature and O2/Ar in the Gas Mixture

Titanium oxide thin film compounds were grown on p-type Si (100) and BK7 glass as substrate using reactive DC magnetron sputtering. The effect of temperature growth on structural, optical and morphological properties was investigated. By means of X-ray diffraction (XRD) the phase composition was characterized. UV–Vis-NIR spectroscopy was used for reflection and transmission measurements of deposited thin film layers. Atomic force microscopy was used to evaluate and compute the surface roughness changes for different temperatures growth. The XRD results show that the temperature growth effects on the phase formation and structure. Increasing the substrate growth temperature would result in change of film thickness due to different phase and structure formation. The calculated band gap from optical measurements of the thin films shows a decrease at higher substrate temperature growth.