Lift-Off Characteristics and Flame Base Structure of Coal Seeded Gas Jet Flames

An experimental study of the burner rim stability characteristics and the flame base structure of flames co-fired with pulverized coal and propane gas is presented. Lift-off and reattachment characteristics are examined as functions of propane concentration in the jet stream for lignite, bituminous and anthracite coals. The effects on flame base structure are studied in terms of temperature, product species concentration and radiation profiles. The addition of lignite and anthracite coals favours the lift-off transitions. Bituminous coal, on the other hand, makes the flame more stable. The peak values of temperature and concentrations of major combustion product species in the flame stabilization region strongly depend upon the rank of coal. Among the coals tested, bituminous coal produces the highest peak temperature and its flame emits maximum radiation from the stabilization region. Anthracite and lignite coals produce somewhat comparable stability characteristics and structure of the flame base. The effects of coal rank are explained by the differences in volatile matter, moisture and pyrolysis characteristics of coals.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Mobile multicast source support in PMIPv6 networks

With the widespread use of multimedia contents via mobile nodes (MNs), IP mobile multicast becomes more important for wireless, mobile, and ubiquitous multimedia applications. Until now, many research efforts have been made to provide IP multicast for the MNs. However, the existing mobile multicast schemes mostly focus on the mobility of receivers based on the host-based mobility solution that requires the MN to participate in the mobility management. Recent work has shown that service connectivity for mobile multicast sources is still a problem and attracts very little concern. With the development of the network-based mobility support protocol, mobile multicast source support schemes in Proxy Mobile IPv6 (PMIPv6) networks are needed urgently. In this paper, we propose a base solution (BS) and also a direct multicast routing scheme (DMRS) for mobile multicast source support in PMIPv6 networks. In the BS, the multicast listener discover (MLD) proxy function is adopted to transmit multicast data through the PMIPv6 tunnel. The DMRS can provide locally optimized traffic flows and avoid inefficient routing present in the BS. We evaluate and compare the performance of the proposed schemes with the Mobile IP bidirectional tunneling (MIP-BT) and Mobile IP remote subscription (MIP-RS) schemes by theoretical analysis and also implement the proposed schemes on the test-bed. The numerical results show that the BS and DMRS outperform the MIP-BT and MIP-RS in terms of signaling cost. Meanwhile, the experimental results verify the feasibility and validity of our proposed schemes. Furthermore, we study the optimal PMIPv6 domain size to reduce the total signaling cost for the proposed schemes

Measurement Techniques for Estimating Local and Total Duct Leakages in Residential Buildings

The paper proposes two measurement techniques for estimating the duct leakage in residential buildings. The first technique determines the “local” leakages using commercially available zone bags and it is called the zone bag-based measurement technique. Zone bags are used to block the flow of air in ducts so that portions of the duct can be isolated and pressurized separately to measure the respective leakages. The thrust of this technique is to locate where these potential leaks are in the duct system and try to provide more cost effective ways to remedy those leaks than what is available currently. The other technique determines the “total” supply and return leakages using a simple model and it is called the model-based measurement technique. The model is based on pressure drop measurements between the return and supply sides. The proposed techniques were evaluated and validated at the air duct leakage laboratory which has two different air duct configurations and a wide range of leakage levels controlled by holes created at several locations of duct work. Experimental results indicate that the zone bag-based measurement technique estimates the local leakage accurately with a mean absolute difference of 0.26% of total air-handler flow compared to the baseline. It can be inferred that this method gives a better estimate of the total leakage based on the location of the leak than the duct pressurization method that uses the half plenum pressure technique. The results also show that the model-based measurement technique is a good alternative when one cannot use a physical barrier between the return and supply sides. It was found that the total supply or return side leakage was estimated with a mean absolute difference of 0.6% compared to the baseline technique. The future research step is field testing techniques to examine how one can more efficiently sample the duct system by judicially sectioning off the duct at a few points to obtain localized leakage information and obtain enough information to correct leak problems