Xu X.,Jilin Electric Power Research Institute |
Chen H.-L.,Wenzhou University
Soft Computing | Year: 2014
Bacterial foraging optimization (BFO) is predominately used to find solutions for real-world problems. One of the major characteristics of BFO is the chemotactic movement of a virtual bacterium that models a trial solution of the problems. It is pointed out that the chemotaxis employed by classical BFO usually results in sustained oscillation, especially on rough fitness landscapes, when a bacterium cell is close to the optima. In this paper we propose a novel adaptive computational chemotaxis based on the concept of field, in order to accelerate the convergence speed of the group of bacteria near the tolerance. Firstly, a simple scheme is designed for adapting the chemotactic step size of each field. Then, the scheme chooses the fields which perform better to boost further the convergence speed. Empirical simulations over several numerical benchmarks demonstrate that BFO with adaptive chemotactic operators based on field has better convergence behavior, as compared against other meta-heuristic algorithms. © 2013 Springer-Verlag Berlin Heidelberg.
Chen T.,Jilin Electric Power Research Institute
Chinese Journal of Endemiology | Year: 2014
Objective To compare the effectiveness of two kinds of defluorinating agents (bone char and modified clay) for removal of fluoride in drinking water, and to analyze their application feasibility in small towns. Methods Influencing factors on defluorinating efficiencies of the two kinds of defluorinating agents under the same conditions were studied, namely the effects of adsorption time, temperature, pH, common anions and cations, and solid-liquid ratio on defluorinating efficiencies were studied. The defluorinating efficiencies of the two kinds of defluorinating agents were validated by original groundwater in Jilin Province. The homemade bone char defluorinating agent and modified clay defluorinating agent were regenerated by NaOH and Al2(SO 4)3, respectively, and their regeneration abilities were investigated. Results The adsorption data of the two kinds of defluorinating agents were fitted Langmuir model well, and the maximum adsorption capacities were 10.225 g/kg(bone char) and 0.587 g/kg (modified clay). The effect of temperature on defluorinating efficiencies was limited, with increasing temperature( 10 - 35 °C ), the adsorption capacity of bone char and modified clay for fluoride ranged from 1.568 g/kg to 1.598 g/kg and 0.423 g/kg to 0.470 g/kg, respectively. Fluoride could be easily removed under low pH conditions, with increasing of pH(4 - 10), the adsorption capacity of bone char and modified clay for fluoride decreased from 1.598 g/kg to 1.523 g/kg and 0.724 g/kg to 0.320 g/kg, respectively. The defluorinating efficiencies were improved by common cations(Ca2+) in groundwater, and the adsorption capacity of bone char and modified clay for fluoride increased to 1.713 g/kg and 0.485 g/kg, respectively. Whereas, the defluorinating efficiencies were inhibited by common anions(HCO3 -, SO4 2-) at a certain degree, and the adsorption capacities of bone char and modified clay for fluoride were decreased to 1.158 g/kg(HCO3 -) and 0.237 g/kg(SO4 2-), respectively. Defluoridation bone char could be regenerated by soaking in NaOH, and modified clay by immersion in Al 2(SO4)3. The adsorption capacities of the two defluorinating agents that had been regenerated for three times still reached 94.6% and 97.3% of their original capacities. Conclusions Both of the homemade bone char defluorinating agent and modified clay defluorinating agent have good defluorinating efficiencies and can be regenerated for many times, which are perfectly suitable for application in small towns since they are simple and can be easily applied. The homemade bone char defluorinating agent is suitable for family drinking water and the homemade modified clay defluorinating agent would be more suitable for centralized drinking water.
Zhang R.,Jilin Electric Power Research Institute |
Wu C.,Northeast Dianli University
Lecture Notes in Electrical Engineering | Year: 2016
A vast number of cracks have appeared at the exit of the boiler vertical water wall, which causes the boiler outage during the 350 MW supercritical unit. To solve this problem, we analyze the characteristics of cracks and boiler-related operating curve is in operation. The study found that the main factor leading to the cracks at the exit of the boiler vertical water wall is thermal stress resulted from large-scale temperature deviations between pipes and rapid changes in pipe temperature. The thermal stress generally emerged under the low-load condition after the boiler turns to dry state. In addition, there is a correspondence between vertical water wall tube temperature fluctuations and changes in boiler feed water. We made the three following recommendations for the causes and characteristics of cracks at the exit of boiler vertical water wall. First, it is to minimize this type of boiler long-term low-load operation in the dry state. Second, the operating personnel shall monitor the vertical water wall outlet temperature under the low-load after the boiler turns to dry state. Finally, we increase the adjustment ability of automatic water supply and automatic coal supply to coal–water ratio. © Springer-Verlag Berlin Heidelberg 2016.
Lu Z.-W.,Northeast Dianli University |
Yu J.-L.,Northeast Dianli University |
Zheng L.-H.,Jilin Electric Power Research Institute |
Ge L.-T.,Northeast Dianli University
Gaodianya Jishu/High Voltage Engineering | Year: 2010
International Electrotechnical Commission (IEC) methods for calculating cable ampacity assume that buried cables are surrounded by a single, homogeneous material. These ampacity methods have limited application when a thermal backfill is used. IEC correction methods are presented to calculate cables' ampacity of non-homogeneous soil. Based on the finite difference method of field-circuit coupling theory, a new numerical calculation method of cable ampacity of non-homogeneous soil is presented. The numerical calculation method which is accomplished through the calculation of cable temperature field distribution can deal with any combination of backfill materials that are placed adjacent to the cable. The calculated results show that IEC thermal resistance correction methods can be effectively used to calculate amapcity when the thermal resistivity of the backfill soil is lower. When the thermal resistivity of the backfill soil is higher, IEC calculating ampacities of correction methods are obviously lower.
Liu P.S.,Beijing Normal University |
Du H.Y.,Beijing Normal University |
Du H.Y.,Jilin Electric Power Research Institute
Materials and Design | Year: 2011
Three dimensional reticulated porous metal foams are widely used engineering materials. A failure model with the simplified structure of these porous materials has been established, and the failure modes have been analyzed for the corresponding porous components under several typical loads, which include torsion, shearing and bending. The failure modes cover the tensile fracture, the shearing and the buckling of the strut, which may lead to the final destruction of the whole porous structure. The mathematical relationships, which characterize different failure modes, have been derived for the strut failure resulting from loading for these porous components under the above loading conditions. The results also show that the failure mode is related with the material species for these materials under the above loads. The tensile fracture of the strut will occur for the porous body with metallic materials in most cases, and the shearing fracture of the strut may occur for that in a relatively little cases. Moreover, the elastic buckling, the elastic-plastic buckling and the edge yielding may also occur on the strut of porous bodies when certain conditions are met. © 2011.