A fast tag identification anti‐collision algorithm for RFID systems

In this work, we propose a highly efficient binary tree‐based anti‐collision algorithm for radio frequency identification (RFID) tag identification. The proposed binary splitting modified dynamic tree (BS‐MDT) algorithm employs a binary splitting tree to achieve accurate tag estimation and a modified dynamic tree algorithm for rapid tag identification. We mathematically evaluate the performance of the BS‐MDT algorithm in terms of the system efficiency and the time system efficiency based on the ISO/IEC 18000‐6 Type B standard. The derived mathematical model is validated using computer simulations. Numerical results show that the proposed BS‐MDT algorithm can provide the system efficiency of 46% and time system efficiency of 74%, outperforming all other well‐performed algorithms.     

Heat transfer augmentation in a wedge-ribbed channel using winglet vortex generators

Experimental investigations have been carried out to study the effect of combined wedge ribs and winglet type vortex generators (WVGs) on heat transfer and friction loss behaviors for turbulent airflow through a constant heat flux channel. To create a reverse flow in the channel, two types of wedge (right-triangle) ribs are introduced: wedge ribs pointing downstream and pointing upstream. The arrangements of both rib types placed inside the opposite channel walls are in-line and staggered arrays. To generate longitudinal vortex flows through the tested section, two pairs of the WVGs with the attack angle of 60° are mounted on the test channel entrance. The test channel has an aspect ratio, AR = 10 and height, H = 30 mm with a rib height, e/H = 0.2 and rib pitch, P/H = 1.33. The flow rate in terms of Reynolds numbers is based on the inlet hydraulic diameter of the channel ranging from 5000 to 22,000. The presence of the combined ribs and the WVGs shows the significant increase in heat transfer rate and friction loss over the smooth channel. The Nusselt number and friction factor values obtained from combined the ribs and the WVGs are found to be much higher than those from the ribs/WVGs alone. In conjunction with the WVGs, the in-line wedge pointing downstream provides the highest increase in both the heat transfer rate and the friction factor while the staggered wedge pointing upstream yields the best thermal performance.     

Antioxidant activities of Thai pigmented rice cultivars and application in sunflower oil

An analytical comparison for active chemical compounds and their antioxidant activities between three representative pigmented Thai rice cultivars was performed. It was revealed that the darkest purple‐red cultivar (Kum Doi Musur, KDM) contained the highest total phenolic content of 1164.6 mg gallic acid equivalent per100 g (dry basis, db) and the highest total monomeric anthocyanin content of 381.7 mg per100 g (db), when compared with the purple cultivar (Riceberry) and the red cultivar (Sungyod). Its 2,2‐diphenyl‐1‐picrylhydrazyl radical scavenging activity and ferric reducing antioxidant power were also the highest. When applied in sunflower oil, the KDM crude extract was efficiently capable of retarding lipid peroxidation as assessed by peroxide value, p‐anisidine value, totox value and the Rancimat method. Results show this specific pigmented rice to be a potent antioxidant for stabilisation of sunflower oil.