Papers by Keyword: Red

Abstract: Red and brown mud is created in the processing of bauxite into Al₂O₃. The chemical composition of red and brown mud depends upon the method of processing bauxite on a mud landfill, and the time and availability of mud leaching by rain. Samples of red mud from landfill in Žiarska Kotlina had pH values of 9.46 ± 0.11 and brown mud had 10.2 ± 0.15. We studied the development of changes in pH and concentrations of Fe (spectrometrically with AAS) in eluates during the leaching of red and brown mud samples. Results show that there is no release of Fe during brown mud elution. When using 0.025 and 0.05 M H₂SO₄ for elution, the pH decreased slightly from 10.2 ± 0.15 to 2.4 ± 0.05. Elution of 0.1 M H₂SO₄ shows that pH decreased to a value of 2.2 ± 0.05 by the 40th fraction and then it fell to a value of 1.77 ± 0.04 in the 100th fraction. The greatest amount of iron was released in the 8th and 55th fraction at a pH of 2 – 4 which could be observed by the change in colour of eluates. The progress of the release of iron was similar for both kinds of mud. Then we determined the neutralisation capacities of various fractions of mud in H₂SO₄, NaOH and H₂O leachates by titration. It was discovered that the reaction of the alkaline proportions of red mud with the agent is greatest with fine granularity but for red mud, it does not change depending upon the size of the grain. The release of acid proportions depended upon time not upon texture. When leaching with water, the leached alkaline compounds from brown mud are mainly from the finest particles, and in the case of red mud, it was the opposite, from the largest particle fraction.

Abstract: As the study on and promotion of wireless sensor networks (WSN) are deepening, people have increasingly higher requirements for the transmission speed and transmission performance of wireless sensor networks. Network congestion is an important factor of the transmission performance of a network, so congestion control becomes a hot research topic in the studies on the improvement of WSN services. Based on the study on WSN congestion control mechanism, this paper proposes an adaptive congestion control algorithm and simulates the algorithm. The simulation result shows that this algorithm can ensure stable network performance.

Abstract: The distributed control of complex and dynamic manufacturing systems is a challenging task and the multi-agent system (MAS) becomes a suitable solution due to its flexibility in both distributing and integrating software functionalities across the controlled system. This paper investigates the potentials of improving agent message delivery by enhancing the underlying communication network with IP QoS mechanisms using service differentiation and early congestion avoidance techniques. The extensive simulation experiments demonstrated the effectiveness of our approach in providing small latency, small jitter and improved throughputs in ACL message delivery, whilst without deteriorating other data applications between distributed controllers.

Abstract: Active queue management algorithm works at network routing node. It notifies terminal system control transmission rate in advance with discard or mark packet before buffer queue overflows, so as to avoid congestion. Aiming at characteristics of wireless sensor network (WSN) and based on introduction of traditional RED algorithm, the paper introduced H parameter to represent traffic similarity to original linear relationship between packet loss probability and average queue length to form the non-linear relationship related to self-similarity. Then a kind of improved RED algorithm of WSN oriented to self-similar traffic was proposed. The detail implementation flow was also provided. Simulation based on OPNET shows that the improved RED is superior to traditional RED algorithm in steady performance.

Abstract: Multiternary nitride and oxynitride compounds doped with rare earth ions, such as Eu2+ and Ce3+ have been enthusiastically applied as various phosphors to white LED. New red and green phosphors, CaAlSiN3:Eu and Ba3Si6O12N2:Eu, have been successfully synthesized, recently. The red phosphor has intense emission around 650 nm under two different irradiations at 405 and 455 nm from blue- and near UV-LED chips, respectively; while strong emission is observed around 520 nm from the green phosphor. Both phosphors also show small thermal quenching over the temperatures up to 150 °C. In addition, both LaSi3N5:Ce and La3Si8O4N11:Ce in lanthanum silicon nitride and oxynitride were examined as candidates for a blue phosphor in white LED with near UV-LED chip.