A review paper concerning wide-band and ultra-wideband (UWB) antennas used for wireless communication purposes in terms of the materials as well as a numerical analysis is presented. These antennas which are taken into account are listed as wide-band microstrip antenna, wide-band monopole antenna over a plate, wide-slot UWB antenna, stacked patch UWB antenna, taper slot (TSA) UWB antenna, metamaterial (MTM) structure UWB antennas, elliptical printed monopole UWB antenna, and flexible wearable UWB antenna. The antennas’ performance is compared based on their size and how they can be applicable for portable communication device applications. This review paper furnishes a proper direction to select varieties of figures in terms of impedance bandwidth, gain, directivity, dimensions, time domain characteristics, and materials affecting these antenna’s characteristics.

In this study, a polypyrrole-chitosan layer was applied to detect zinc and nickel ions in aqueous solution using surface plasmon resonance. The resonance angle shift was found to monitor the binding interaction between ions and the polymer film. The polypyrrole-chitosan film was coated on the gold layer with an electrochemical deposition method. The Langmuir model was compared with the Freundlich model to explain the binding. Consequently, the Langmuir model was fitted with experimental data better than the Freundlich equation, and the detection limit was 0.01 ppm.

Water conservation and prevention of salt accumulation are important issues in arid and semi-arid regions. Mulching is the most frequently used method for water conservation and prevention of salt accumulation. A mulch with various layers, hence named layered mulch (LM), was applied for reclamation of saline soil. The LM comprises of a light-colored mineral, farmyard manure, and common reed (Arundo donax L.). Two treatments, one with LM and the other without LM (NLM), were carried out on saline soil for 2 years. Soil temperature, water content, and electrical conductivity (EC) were measured during March and September at the depths of 1 to 120 in 4 cm intervals. The results showed that LM soil had a lower temperature and EC than NLM soils. The LM soil recorded higher soil water content than the NLM soil. The LM soil had a lower temperature possibly because it reflected the sunlight, had high heat capacity, and was less permeable to heat conduction. Consequently, the lower temperature in LM soil resulted in higher soil water content and this can be a soil condition, that enables enhanced salt leaching by subsequent rains.

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