Керовані планарні фільтри НВЧ із рухомим електродом

Запропоновано новий спосіб управління резонансной частотою резонаторів і фільтрів НВЧ. Реалізованно ідею п’єзоелектричного управління ефективною діелект- ричною проникністю $\left(\varepsilon_{\text {eff }}\right)$. Між підкладкою і земляним електродом передбачено тонкий повітряний зазор, величина якого контролюється за допомогою п’єзоелектричного актюатора.
Ключові слова: планарні фільтри, електромеханічне керування, НВЧ.

Superabsorbent Hydrogel from Extracted Oil Palm Frond Waste Cellulose Using Microwave Irradioation for Cadmium Ion Removal from Aqueous Solution

This research report facile approach on dispersion of cellulose fiber extracted from oil palm frond waste in a “green-solution” prepared by using urea and sodium hydroxide while the polymerization is carried out using microwave to form hydrogels. Effects of adding cellulose was determined by comparing the swelling degree between 0% and 2% cellulose hydrogel. Results showed that swelling ratio enhanced by the presence of cellulose. SEM images exposed that hydrogel with cellulose has rough surface compared to the hydrogels without cellulose.

Removal of Methylene Blue by Adsorption onto Activated Carbons Produced from Agricultural Wastes by Microwave Induced KOH Activation

The present study aims to describe new low cost activated carbons which were prepared from bean peel (BP), acorn peel (AP) and Pistacia lentiscus (PL) under microwave induced KOH chemical activation for the removal of methylene blue dye from aqueous solutions. Activated carbons were characterized using, thermogravimetric analysis, and scanning electron microscopy. The adsorption properties were examined considering several parameters including the effect of pH, contact time, adsorbent dosage and initial concentration.