bluuebunny/crossref_metadata_2025 huggingface dataset:
An Adaptive Hysteresis Band Controller for Single Phase PV Inverters
Authors: Xia Yang , Tao Hai Liang , Zhang Ning
Published: October 2011

Hysteresis current controllers are widely used in PV inverters. The main drawback of conventional hysteresis current control is that the switching frequency is variable, as the hysteresis band is fixed. In this paper an adaptive band hysteresis control algorithm with no derivative calculation is presented. As it will be shown, this algorithm can limit the switching frequency variation within a small range and the algorithm itself is simple and easy to be implemented. The performance of this algorithm, together with the one [10] and conventional hysteresis control has been evaluated by means of simulations performed with PSIM and SIMULINK. Simulation results show the effectiveness of the suggested hysteresis current controller.
Research on High-Power Power Factor Corrector of Power Electronic Transformer
Authors: Jiang Jian Feng , Yang Xi Jun , Jiang Jian Guo , Lei Huai Gang
Published: October 2011

Power electronic transformer (PET) which has a big potential application value in smart grid is an electrical power transformer device adopting power electronic converter and high frequency switch transformer. A new PET with power factor correctors (PFC) is proposed in this paper. Due to high power level of PET, PFC should have a high power level as well. Therefore, the multi-phase interleaved PFC is employed. The paper describes the one cycle control principle, proposes a current synthesis method based on IGBT current, and then analyses the relationship between ripple current and duty cycle of IGBT. In addition, the whole PFC system is simulated completely by means of Matlab/Simulink. In order to verify the theoretical analysis and simulation analysis, a four-phase interleaved PFC with a rated output power of 8.0kW is designed and implemented based on the an analog control chip. The obtained results show that the interleaved PFC by means of one cycle control and current synthesis is feasible, capable of reaching a good suppression effect of ripple current.
A Study of Topology Based on Matrix Rectifier and AC Chopper Principle
Authors: He Mei Sheng , Zhu Jian Lin , Zheng Rong , Chen Wei Ming , Chen Yao Feng
Published: October 2011

A new frequency conversion device topology based on matrix rectifier and AC chopper called MCAC） is proposed, which is referred as AC chopper matrix converters. First, the basic configuration of these new topologies and the fundamental principle are introduced. Then, the validity and feasibility of the new topologies are tested by digital simulation and prototype experiments. The results indicate that the output voltage transfer ratio can be larger than 1.0, the output voltage waveform is very close to standard sine wave and the harmonic contents increase slightly, overcoming the drawbacks of conventional MCs that maximum voltage transfer ratio is 0.866. This study may provide inspiration for further engineering applications.
Microbial Screening Strategies for Biodegradation of Monocyclic Phenolic Compounds
Authors: Xiao Zi Jun , Qi Rui Qian , Huo Fang Fang , Huang Yun Ling , Xu Hai , Lu Jian R.
Published: October 2011

Wastewaters discharged from oil refineries and coal coking plants often contain large amounts of toxic monocyclic phenolic compounds (MCPCs), mainly including phenol, cresols and xylenols, polluting soils and surface water. In this work, crude phenols or 12 individual MCPCswere used as the enrichment medium and the later strategy was discovered for the first time to be more effective in finding more and competent MCPC-degrading strains. Phylogenetic analysis and multiple MCPC degradation tests revealed that phylogenetically close microbes generally exhibited similar MCPC-degrading spectra.
Research of Isolated Three-Level AC-AC Converter
Authors: Zhu Ling , Li Lei
Published: October 2011

To be used for voltage regulator, An AC-AC direct converter with small bulk has been researched. The paper has proposed an isolated Cuk Three-Level AC-AC Converter. It is produced by applying TL AC switch unit in Isolated Cuk converter which is put forward by Slobodan Cuk. Because the two-level converter usually isn’t used in high voltage and heavy load situation, the paper proposed the cascaded type of isolated Cuk AC-AC converter. Besides, the operating principle and the control strategy of isolated Cuk Three-Level AC-AC Converter are investigated. Transient voltage feedback control is used in the converter and principle diagram of control circuit is given. By experiment results, the correctness of operating principle and control strategy of isolated Cuk Three-Level AC-AC Converter have been proved.
The Fault Line Selection Method of Small Current Grounding System Based on Wavelet Transformation
Authors: Li Hua , Li Ling Ling , Huang Shan Shan , Li Feng Qiang
Published: October 2011

In order to make full use of small current grounding system transient information and to improve the accuracy of fault line selection, a method based on wavelet transformation was proposed. On the basis of wavelets transformation theory and its characteristics, a proper wavelet function was chosen up to take wavelet transform to collected fault data, and then to get the fault line according to the modulus maxima theory. The MATLAB simulation results show the effectiveness of the proposed techniques on improving the accuracy of fault line selection.
Weakly Compressible Fluid Model to Study Thermal Effects on Laser Propagating in Closed Tube
Authors: Liu Jian , Wang Shi Qing
Published: October 2011

Analyzed the iso-pressure approximate model used in laser propagation in gas medium and pointed out its disadvantage under complex border conditions. The weakly compressible fluid model was developed which was based on the Mach uniform method introduced by Peter Wesseling. Using the weakly compressible fluid model and scalar wave equation, a numerical study was carried out for the gas thermal effects on laser propagating in a closed tube full-filled with air. The far-field beam shape at different time were obtained and compared with the experiment ones. It is shown that the weakly compressible fluid model could be well adapted for problems with complex border conditions, acute than the compressible fluid model or the iso-pressure approximate model.
Couette Flow of a Generalized Oldroyd-B Fluid due to Constantly Accelerated Shear Stress Coupled with the Pressure Gradient
Authors: Li Chun Rui , Zheng Lian Cun , Zhang Xin Xin , Niu Jia Jia
Published: October 2011

This paper presented an analysis for the couette flow of a generalized Oldroyd-B fluid within an infinite cylinder subject to a time-dependent shear stress with the influence of the internal constantly decelerated pressure gradient. The exact solutions are established by means of the combine of the sequential fractional derivatives Laplace transform and finite Hankel transform and presented by integral and series form in terms of the Mittag-Leffler function. Moreover, the effects of various parameters are analyzed in detail by graphical illustrations.
Wall Shape on the Influence of the Spray Wall-Impingement under Common Rail System
Authors: Du Hui Yong , Zhang Pei Hong , Liu Jian Xin , Wang Zhan Cheng , Xu Bin
Published: October 2011

In this article, the spray wall-impingement experiments were carried out under the common rail condition by image acquisition system to study the wall shape impact on the diesel spray impingement. The results showed that the scatter direction of impinged spray, shape of impinged spray can be changed by the wall shape significantly. With the increasing of injection pressure, spray splash volume relatively increases and atomization is enhanced when the spray impinges on a flat wall; the development of distance along the wall is nose-shape 90 degree > 135 degree.
The Research on Ammonia Nitrogen Transport in Different Kinds of Soil
Authors: Rao Wei Guo , Zhang Zhi Hong , Xu Zhao Gang
Published: October 2011

The study on transport regularity of contamination can provide theoretical evidence for forecasting the potential hazard of contamination to underground water environment and safety disposal. In this paper analytic solution of transport model on ammonia nitrogen in soil under the condition of unchangeable contamination concentration. According to model solution transport situation of contaminant on different kinds of soil which are clay, heave silt clay, silt clay and clay silt has been simulated. The results have shown that the obstruct performance to contaminant of clay is the best and the obstruct performance to contaminant of clay silt is the worse.
Precision Cultivation of Phaeodactylum tricornutum and Free Lipid Acid Analysis
Authors: He Feng , Fu Peng Cheng , Xu Chun Ming
Published: October 2011

Abstract：A field test was conducted on a photobioreactors for cultivaion of P. tricornutum for optimization cultivation conditions.Here,we use a flat-cuvette pohotobioreactor to control the irradiance, pH, gas composition combined with on-line monitoring by fluorometer and densitometer.By chosing the culture medium in containing glucose，sodium acetate and glycerol, to check for the biomass, cell concentration, biochemical substances and fatty acid content nearly three months . The results show that: Phaeodactylum tricornutum is not only photoautotroph but also mixotroph, which with selectivity for substance concentration and organic carbon sources, the optimum concentration of glucose is 20mmol/L, the optimal growth condition in 500mL flask contains that the temperature is 25±1°C, the light intensity is 50µmol/m2.s, the pH is 8.5. Whatever the carbon sources are able to promote the biomass accumulation. When the cell concentration achieve to 2.5×106 cells/mL in the end of the culture, analyzed total lipid content so as to determine the biomass accumulation and biomass variation in different growth conditions. By ultrasonic extracting and freeze drying, the total of lipid reaches 20%(dry weight); the main content of fatty acid is C16:0,C18:0,which is the better material for biodisel production.
The Influence of Thickness of Nitrocellulose Wood Lacquer on Formaldehyde Emission Rates
Authors: Xiao Xue Jiao , Deng Bao Qing , Zhang Peng , Zang Yun Lin , Zhu Meng Ling , Liang He Meng
Published: October 2011

This study aimed to investigate the influence of the paint film thickness on formaldehyde emission rates. A small-scale environmental chamber was set up to test the formaldehyde emission from wood lacquer with different thicknesses. In all experiments, the temperature, the airflow rate and the relative humidity were the same, which were set to 23 °C, 1000 L/s, 45 %, respectively. The emission rates of formaldehyde were calculated through the double exponential decay model. Results showed that the peak concentration was dependent of the paint film thickness. The thicker the film thickness was, the slower the emission rate was.
Influence of Coil Inclined around Y Axis on Thermomagnetic Convection of Air in a Porous Cubic Enclosure under Zerogravity
Authors: Jiang Chang Wei , Zhu Xian Feng , Shi Er , Zhou Zhen
Published: October 2011

Thermomagnetic convection of air in a porous cubic enclosure with a electric coil inclined around the Y axis is numerically investigated under zerogravity environment. The porous cubic enclosure is heated isothermally from left-hand side vertical wall and cooled isothermally from opposing wall while the other four walls are thermally insulated. The governing equations in primitive variables are discretized by the finite-volume method and solved by the SIMPLE algorithm. The results show that the overall heat transfer is enhanced gradually with the increase of magnetic force number and Darcy number. The resulted convection is symmetrical in terms of the angle at yeuler =0 when the range of inclination angle is from -90 to 90.
The Application of Mathematical Model and Numerical Simulation in the Pneumatic Drying of the Straw
Authors: Lv Wei , Li Rui Yang , Wang Xin Hai , Li Yan Dong , Sun Hong Wei
Published: October 2011

According to the analysis of the characteristics of the biomass straw in its pneumatic drying process, some reasonable assumptions concerning the pneumatic drying are made and the mathematical model of heat and mass transfer in the biomass straw’s pneumatic drying process in the horizontal straight tube. Besides, the numerical method is adopted to solve the model and the analog simulation concerning the moisture content, temperature and the speed changes of the material and the air is conducted. Meanwhile influence of the gas-solid ratio and the air flow’s initial temperature on the drying effect is the analog simulated and the reason for this phenomenon is also analyzed.
Study on Mathematical Simulation of Nitrogen Oxides (NOx) Formation of Coal-Fired Boiler
Authors: Heng Li Jun , Duan Kun Jie , He Chang Zheng
Published: October 2011

There exist certain limitations to research the law and influence factors of the nitrogen oxides formation only with the help of field tests, because the nitrogen oxides formation of the boiler is influenced by various factors. The flow, combustion mathematical models interrelated and so on are established taking the 410t/h boiler fired tangentially as a prototype by the use of the fluent software. All the mathematical models are verified and modified with the aid of routine field test data, and the accuracy and reliability of the mathematical models are improved. Then NOx formation performance is stimulated in allusion to the influence factors without field test conditions. The mathematical simulation results show that mathematical models can provide a sufficient theoretical basis to analyze accurately combustion and NOx formation law in furnace, and the deficiencies of field tests have been made up.
Experimental Investigation on Flow Patterns of Cylindrical-Conical Spout-Fluidizing Bed
Authors: Li Qian Jun , Zhang Dong Ping
Published: October 2011

Experimental investigations on hydrodynamic characteristics of cylindrical pressurized spout-fluidizing bed were carried out. Two kinds of millet were used as bed materials. The operational pressure is 0.1MPa~0.4MPa (absolutely pressure). Five distinct flow patterns, i.e, fixed bed(FB), jet in fluidized bed with bubbles(JFB), jet in fluidized bed with slugging(JFS), spout with aeration(SA) and spout-fluidizing bed(SF) were identified. Effects of the static bed height and operational pressure on the flow pattern map were particularly studied. Typical flow pattern images obtained by a high- resolution digital CCD camera were presented for classifying these flow patterns. Typical flow pattern maps were plotted for describing the transitions between flow patterns with operating conditions
Catalysis Reduction of NO and HCN/NH3 during Reburning: a Short Review
Authors: Su Ya Xin , Deng Wen Yi , Shen Heng Gen
Published: October 2011

Reburning is effective to control NO emission. The paper presents a short review on recent research on catalysis reduction of NO and HCN/NH3by some metal and their oxides during reburning. The major difficulties that limit NO reduction efficiency by reburning involve the re-oxidation of the intermediate products during reburning, HCN/NH3and char nitrogen to NO. So far, results showed that Fe2O3could reduce the formation of HCN/NH3after reburning and metallic iron could directly reduce NO to N2. Temperature and co-existing gases influenced the catalysis performance of Fe and its oxides. Detailed mechanism and kinetics of the reactions should be further investigated.
Experimental Investigation and Comparison on Fin Surfaces Performance of Flat Tube Heat Exchangers
Authors: Dong Jun Qi , Chen Qian , Wei Wu Jie
Published: October 2011

An experimental study has been carried out to investigate the heat transfer and pressure drop characteristics of flat tube heat exchangers with plain, wavy, louvered and offset strip fin surfaces. Results are presented as plots of Colburn j factor and friction factor f against Reynolds in the range of 600-6500. Additionally, the dimensional heat transfer coefficient and pressure drop are presented as a function of frontal air velocity. Finally, two comparison methods are adopted to evaluate the air side performance of the plain fin, wavy fin, louvered fin and offset strip fin surface. The results show that the offset strip fin has the best performance of heat transfer enhancement.
A SOA-Based Power Quality Management Platform
Authors: Zhang Yi , Yang Hong Geng , Ye Mao Qing
Published: October 2011

To reuse the existing power quality systems; share the information and support the changing of management business process in power quality, a power quality management platform based on Service Oriented Architecture (SOA) is proposed. The platform architecture is divided into five layers; the components of each layer are expounded. A business process of disturbance load evaluation implemented by Business Process Management (BPM) is illustrated. By using the architecture in real systems, conclusion can be made that the proposed architecture is feasible.
Model Analysis of Car’s Body-in-White Based on FEA
Authors: Wang Yuan , Xu Li , Dai Xi Liang , Peng Sheng Hui
Published: October 2011

In this paper, the finite element model of some car’s body-in-white is established in Hypermesh. The model analysis is executed based on the element model in ANSYS. Through the model analysis the dynamic parameters of the body-in-white are obtained. At the same time，the modal test of a real car body is implemented. The reliability of the finite element model is validated based on the modal test. The results show that the stiffness of the body-in-white is great enough and it can provide optimal design for future designers.
Fault Diagnosis for Wind Turbines Based on Vibration Signal Analysis
Authors: Zhen Cheng Gang , Zhang Yin Yin
Published: October 2011

Fault diagnosis is an important technical method to improve the safety index and economic effectiveness of wind turbines, it also provide support to advanced maintenance and design in wind power equipment. In this paper, we have done vibration testing on two wind turbines, one is in normal, the other is with faulty, and then carried on comparative analysis of vibration signal to the experimental data, finally designed a fault diagnosis method for direct-driven wind turbine generators.
Experimental Study on Atomization Characteristic of Fuel Injector of Heavy-Duty Gas Turbine
Authors: Liu Kai , Zhang Bao Cheng , Ma Hong An
Published: October 2011

Experimental investigation results of the fuel injector group in a heavy-duty gas turbine are presented. Atomization characteristic has great impact about combustion, inflame, temperature field of outlet. Obtained atomization characteristic about spray particle size and spray angle using LDV/PDPA system, determined dimension of injector group. On the basis of these tests, the combustion testing of the injector group in the flame tube is made, its every targets are arrived in the design requirements. This has demonstrated: the test systems and test methods are practical, feasible and reliable. These experimental data have provided the reliable basis for the injector group design and development.
Study on the Methanol Percentages Effect on Combustion and Emission of DME/Diesel Blended Fuel
Authors: Li Yu Juan , Wang Tie , Zhang Cui Ping , Zhai Xu Mao , Lei Si Min , Liu Wei Wei
Published: October 2011

An experimental investigation was conducted on 4100 engine to study the influences of different percentages of methanol in DME/diesel blended fuel on combustion and emission performance. The result indicates that a certain amount of methanol in DME/diesel blended fuel can reduce production cost, improve the engine's power performance at the same time, but when the methanol percentage is increased (over 2%), the power performance will decrease. With the increase of methanol proportions, the maximum cylinder pressure is slightly increased, the peak of heat-release curves are declined and delayed, the cylinder temperature is decreased, the ignition timings are delayed and the combustion duration is shortened. In addition, NOx emissions were further reduced, but the HC emission, the CO emission and the soot emission has a little rise.
Effect of Top-Layer Thickness on Thermal-Shocking Property of Plasma-Spraying Sm2Zr2O7/YSZ Thermal Barrier Coatings
Authors: Zhang Hong Song , Wei Yuan , Chen Xiao Ge
Published: October 2011

In this paper, effect of top-layer thickness on thermal-shocking property of plasma-spraying DCL coating of Sm2Zr2O7and YSZ was studied by FEM. Results show that radial stresses decrease with time increasing, and their maximum values are increase with top-layer thickness increasing. They have similar distributions along horizontal distance which decrease gradually with increasing top-layer thickness. Radial stresses at YSZ layer/ bonding layer remians almost compressive stresses state which is helpful to increase bonding strength the TBCs. Axial stresses remians almost unvariable along horizontal distance in the range from 0mm to 15mm, they change abruptly from negtive stresses state to positive stresses state at edge of TBCs sample. Axial stresses also decrease gradually with increasing top-layer thickness.
Numerical Simulation of Turbulent Mixing for Dislocated Blades in a Stirred Tank
Authors: Shi Lei , Zhou Shen Jie , Yang Feng Ling , Hu Fan Jin
Published: October 2011

Mixing efficiency is an important parameter in the design of many industrial processes in stirred tanks. In this study, CFD technology was used to simulate the mixing process inside the stirred tank with dislocated blades and standard turbine. Calculations were performed to study the effects of agitator speed and the configuration of impellers on mixing efficiency. The results showed that the flow field in the stirred tank with the dislocated blades is better than the standard turbine, and the flow number of the dislocated blades had been improved while the power number had been reduced. According to calculation results of Wr, we found the mixing efficiency of the dislocated blades had been improved about 4 times than that of standard turbine.
Study on the Flow Field of Jet Plug-in Hot Blast Furnace
Authors: Wang Xue Ping , Zhang Zhen Wei , Zhang Cheng , Zhang Hong Bo
Published: October 2011

This paper primarily focuses on the analysis on the heat exchange part’s flow field of the jet plug-in hot blast furnace, and comprehensively considers the temperature field aiming at obtaining the velocity and pressure distribution of the air and flue gas in each part of the heat transfer. Heat exchange mainly takes advantage of thermal convection about high temperature flue gas of the hot blast furnace and air, the flow situation of which have the direct effects on the heat exchange result in the heat transfer. The authors implemented the numerical simulation on flow field of the jet plug-in hot blast stove in heat transfer by using the method of finite element analysis. The conclusion of this paper provides the basis for the further enhancement of the machine life and optimization of the structure design.
Research of Simulation Model for Non-Linear Turbine Regulating System
Authors: Sun Mei Feng , Wang Rui Lian , Wang Jia , Lu Jing Bin
Published: October 2011

In the large fluctuation transition process of hydropower unit, hydraulic turbine operating condition changes drastically, following the change, hydraulic-turbine transfer coefficients also change drastically, thus the mathematical model of hydro-turbine governing system is nonlinear. This paper establishes simulation model of large fluctuation transition process in SIMULINK software, puts forward a method of establishing simulation model of nonlinear hydro-turbine governing system.
Modeling and Stability Analysis of the Speed Regulating System of a Planetary Mixer
Authors: Yang Ming Jin , Li Xi Wen , Wang Zhi Gang , Shi Tie Lin
Published: October 2011

Hydraulic drive mixers are widely employed to process the cohesive mixture, especially the dusty and energetic mixture. In this study, the modeling method of the AC frequency control speed regulating system of a planetary mixer was presented. The speed regulating system consists of links of frequency converter(FC), asynchronous motor(AM), and hydraulic circuit(HC). The stability analysis was conducted by applying specification parameters of the FC, AM and HC. Result shows that the speed regulating system is stable by Routh criterion with amplitude margin 21.4db and phase margin 17.9degree.
Time Evolutions of Water Drops Impacting on a Rotating Disk
Authors: Li Jing Yin , Yuan Xiao Fang , Han Qiang
Published: October 2011

Experimental studies of a water drop impinging on a rotating disk using a high-speed video camera have been performed. The photos of the impact were analyzed in detail. Three kinds of the deposition patterns were observed with the variation in Rossby number. It is found that Rossby number plays an important role in the deposition process of the drop impacting on the rotating disk, leading to some new stages not observed for drop impact on a stationary plate.
Exergy Analysis and Optimized Power Generation Applied to the Co-Combustion of Sewage Sludge and Coal
Authors: Fang Yu Na , Chi Yong , Jin Yu Qi
Published: October 2011

In this paper, the classical sewage sludge and coal co-combustion power generating system was optimized. The regenerative steam in the extraction turbine was partly used for the sludge drying. And then, the mathematics model was established based on the exergy theory. Several extraction points were compared to find out the most optimization parameters (drying efficiency of the dryer, pressure and tempreture). The result showed that, with different steam temperature and pressure at different extraction points, the influence to the system exergy efficiency caused by the percentage of moisture and drying efficiency was different. When the sludge moisture content went to about 35%, the generating capacity increment was moderating. After the calculation and comparison, the error between the calculation results of the mathematical optimization model and the classical thermodynamic method was very small. The calculation in mathematical optimization model based on exergy analysis was relatively simple, and analysis of the relationship between variables was easier.
Research on Flow and Heat Transfer Characteristics In Micro Heat Exchanger
Authors: Lu Yu Kun , Zhao Kai , Wang Xiao Gang , Liu Hai Feng
Published: October 2011

The flow and heat transfer characteristics of a micro heat exchanger structure are studied with the method of contrasting experiment and Fluent numerical simulation. Considering the micro heat exchanger to meet the work requirements of conditions, there is some optimization of the structure redundancy. The optimal model of micro heat exchanger is obtained by the numerical simulation and comparative analysis on seven different kinds of micro heat exchangers.
Research on the Absorption Characteristics of Activated Carbon Prepared by Biomass
Authors: Wu Jiang , Liu Qian Yan , Meng Shuai Qi , Chen Jie He , He Ping , Ren Jian Xing , Li Fang Qin , He Lu Lu
Published: October 2011

The biomass carbons were studied with ZnCl2 as activating agent, methylene blue as index and its Hg adsorption experiment was conducted. The adsorption of soybean stem activated carbon for methylene blue was 149.84μg/g, and its adsorption capacity to Hg in flue gas in 4 hours was 14.57μg and penetration rate was 5.30% at the conditions of 600°C activation temperature, 90 min activation time and ZnCl2 concentration 50%, and the mechanism was analyzed.
Simulation of Solar Assisted Ground Source Heat Pump System in Different Regions
Authors: Zhou Qin Tao , Dong Hua , Zhou En Ze , Yi Wei
Published: October 2011

This study presents a simulation approach to assess the viability of solar assisted ground source heat pump system in different regions of China. A short time step model of ground loop exchanger is employed in the simulation with a 30% solar fraction. Weather data files used in the simulation are created based on Chinese Typical Year Weather (CTYW) data. Borehole length is optimized with a safety stop temperature of 0°C. The minimum Entering Fluid Temperature (EFT) decreases 1.3°C after 20-year simulation time and the team effect of ground loop exchangers is weaken as a result of spontaneous recovery of storage temperature. Borehole length replaced by area of solar collector ranges from 3.9m to 2.5m in the six cities. The results show that the annual performance of ground loop exchanger is low in heating-dominated regions and a solar assisted ground source heat pump (SAGSHP) system is needed in order to improve the system performance.
The Optimal Operation of Thermal Power Plant Auxiliaries Based on Mixed Integer Programming
Authors: Shu Jun , Li Xiao Li , Chen Qian
Published: October 2011

Optimizing the operation of thermal power plant auxiliaries can effectively reduce the power consumption rate and improve production efficiency. This paper establishes the optimal operation model for variable-speed pumps and fans, which are the main auxiliaries in thermal power plant. The model is based on the operating characteristics of pumps and fans and considers parallel and series operation. The object is to minimize the power of auxiliaries; the constraints contain the requirements of system flow or head, speed limits, flow limits, power limits and pipeline performance. Because of the complexity of the model, the pumps and fans operating performance curves are transferred to piece-wise linear curves at first, then a new 0-1 variable is introduces to characterize the choice of a different Q-P curve at a different speed. The model has been converted to mixed integer linear programming problem and uses commercial modeling tools to solve. The case is to verify the effectiveness of this method.
The Power Quality Analysis and its Enhancement Scheme in Power Distribution of an Automobile Factory
Authors: Yun Wei Jun , Chen Chen , Shen Jing Shuang
Published: October 2011

Nonlinear loads are widely spread in automobile industry along with the development of power electronic technology, which causes proliferation of power quality problems, such as harmonics, voltage fluctuation, etc. The problems result in detrimental effects to the power distribution systems, increasing power loss in the network and affecting the safety operation of electrical appliances. This paper analyzed the power quality problems and proposed an enhancement scheme implemented in an automobile factory. The scheme has already got an application in one of the transformer substations. It’s revealed that the proposed scheme can improve significantly the power factor of the 400V bus in car body workshop, and the harmonics injection to the utility grid can be within the limit of related standard．
Proposal and Preliminary Study on Installed Capacity Margin
Authors: Huang Xun Cheng , Chai Xu Zheng
Published: October 2011

The capacity of thermal power plants takes up 75 per cent of whole power generation capacity in China, and so a reserve of generation capacity margin that may adapt to the variations in power network load is of paramount importance. This paper proposes a concept: installed capacity margin, and basic mathematic modeling and example is analyzed. It would be supply theoretical help for real little thermal power plants shutdown schedules based on building detailed mathematical models after investigation of region-specific load structure characteristics and installed generator compositions.
The Influence of Changes of Soil Parameters for Potential Distribution along the Earth's Surface under 3d Combined-Layer Soil Model
Authors: Li Wen Feng , Yang Hong Geng
Published: October 2011

A new soil model named as 3d combined-layer soil model is firstly proposed. According to the concept of image, the Green function of this soil structure is derived using complex image method. Based on it, the surface potential distribution (SPD) of different soil structure configuration is calculated, moreover, the influence of soil parameters on SPD is analyzed. It can be seen from the results that the variations of the soil parameters such as soil thickness and resistivity can bring different influence to the SPD of the soil, and it is related not only to the distances, but also the angle for the grounding electrode. Therefore, the 3DSM may be more accurate for the calculation of SPD.
Study on Switching Operation in the Simulation and Training System in the Intelligent Substation
Authors: Ran Guang Ying , Liu Jun Zhou , Chen Li Hong
Published: October 2011

This paper analyzes the simulation function about switching operation simulation in the training simulation system of intelligent substation, and proposes a kind of training methods about switching operation, it promote running on duty personnel training, and effectively utilizes the substation simulation training system. At the same time puts forward intelligent reasoning machine system.
The Simulation Platform of 10kV Distribution Network Based on PSCAD/EMTDC
Authors: Xu Bo , Zhang Jun , Cai Xu
Published: October 2011

This paper aims at constructing the 10kV distribution network simulation platform on the principle of the laboratory experiments. This project is done by using the PSCAD/EMTDC software and can simulate all kinds of ground faults in the power grid. The platform can be divided into two parts: the basic framework and the user-defined module. The basic framework includes powers, transformers, lines, control and measurement units. Meanwhile, the user-defined module contains a ground arc module, ground fault modules and arc suppression coil(ASC) modules et al. Furthermore, this paper describes several examples of the single-line-to-ground faults in the resonant grounded network. In the end, the validity of the simulation platform is confirmed by the data comparison with the laboratory experiments.
A Mixed H2/H∞ Based LMI Algorithm for Damping Inter-Area Oscillations
Authors: Ma Jing , Guo Rui , Wang Tong
Published: October 2011

An algorithm of mixed H2/H∞ based LMI algorithm for damping inter-area oscillations is investigated. A feedback controller is designed for such problem, which takes the uncertainty of power system parameter into account. In order to gain desired dynamic and steady state qualities, a pole-placement technique based on Linear Matrix Inequalities is used. At last, simulation of 4-machine 2-area system using this method is carried out, which proves the validity and robust of the designed controller. Different operating conditions are considered to validate the adaptability of this algorithm.
Influence Analyzing of Slope Stability with Setting of Crushing Station in Semi-Continuous Technology
Authors: Peng Hong Ge , Cai Qing Xiang , Zhou Wei , Shu Ji Sen , Li Guo Ji
Published: October 2011

According to the analysis of the semi-continuous mining system with crushing station set on end-slope and the relation with working wall and non working wall, the calculation method of uncovered end-slope area and the coefficient of slope stability was elicited, considering the external load caused by crushing station location. The variation curve and the law of stability coefficient were also obtained. Combining the field practice, the research conclusion indicates that the crushing station setting of semi-continuous mining system would affect not only the truck transportation distance and the economy benefit, but also the slope stability, which can be used as the theory support to the setting of crushing station in semi-continuous mining system.
Partial Nitrification to Nitrite with Real-Time Aeration Duration Control in an SBR Treating Domestic Wastewater
Authors: Chen Yu , Li Jun , Wang C .W , Zhao X.F , Zhao B.H
Published: October 2011

Sustainable partial nitrification to nitrite has been proven difficult in treating low strength nitrogenous wastewater. Real-time aeration duration control was used to achieve efficient partial nitrification to nitrite in a sequencing batch reactor (SBR) to treat low strength domestic wastewater. Above 95% nitrite accumulation ratio was maintained for long-term operation at normal condition. Partial nitrification established by controlling aeration duration showed good performance and robustness even though some time encountering long-term extended aeration. Process control enhanced the successful accumulation of ammonia oxidizing bacteria (AOB) and washout of nitrite oxidizing bacteria (NOB).
Effect of Hydraulic Loading on Removal Efficiency of the Folds Stable Surface Flow Wetland
Authors: Wang Cheng Duan , Fu Hai Xia
Published: October 2011

Three folds stable surface flow wetlands (FSSFWs) were operated at different hydraulic loadings of 0.80, 0.53 and 0.27m3/ (m2•d) to treat the decentralized domestic sewage. And we investigated the effect of the hydraulic loading rate (HLR) on the removal efficiency of FSSFWs by measuring five indicators of chemical oxygen demand (COD), total nitrogen (TN), ammonium (NH3-N), total phosphorus (TP) and suspended substance (SS). The research results indicated that the hydraulic loading had great impact on the removal efficiency of FSSFWs, and was looked upon as one crucial factor for FSSFWs design. The removal efficiency of FSSFWs presented a downward trend in various degrees along with the increase of hydraulic loading. Also the hydraulic loading had greater influences on the removal rate of NH3-N and TN than COD, TP and SS. Considering the operation costs, the treatment capacity and the purification effect in this experiment, we could ensure the efficient and stable operation of FSSFWs with HLR at 0.53 m3/ (m2•d) and HRT at 0.4 m3•d-1, which were the most appropriate options.
Degradation Kinetics and Mechanics of Methylene Blue by Complex Ultraviolet and Hydrogen Peroxide Process
Authors: Xu Hang , Tang Qiang , Liu Ya Na , Jiang Yong , Tang Hong Yan
Published: October 2011

Hyperbolic model could be established to describe the degradation performance of Methylene Blue (MB) using UV/H2O2 process. The effects of initial H2O2 dosage on MB removal, instant ▪OH concentration and reaction rate were investigated. The results show that the optimal H2O2 dosage is 13.24 mM and after 50min the MB removal is around 85%. The MB degradation process is followed the hyperbolic model which can calculate instant ▪OH concentration and reaction rate.
Removal of Chromium(VI) by Zero Valent Iron: Effects of Environmental Factors
Authors: Rao Pin Hua , Zhang Wen Qi , Zhao Jie , Dong Xin Yu
Published: October 2011

The influences of various geochemical factors, such as pH, phosphate, bicarbonate, humic acid, permanganate, and dissolved oxygen, on hexavalent chromium(Cr(VI)) removal by zero-valent iron(Fe0) were investigated in a batch setting. Results showed that low pH environments were favorable to removal of Cr(VI) compared with high pH environments. Phosphate significantly inhibited removal of Cr(VI) possibly due to competition of adsorption sites on corrosion products. Humic acid introduced a marginal influence on Fe0 reactivity toward Cr(VI) reduction, whereas bicarbonate enhanced Cr(VI) removal by maintaining the solution pH near neutral. Permanganate cumbered the removal of Cr(VI) due to its competition for electron from oxidation of Fe0. The removal efficiency of Cr(VI) was higher in oxic conditions than that in anoxic conditions.
Simulation of Simultaneous Desulfurization and Denitrification of Flue Gas Using Pulsed Discharge Plasma
Authors: Zhou Qi , Yu Qi , Li Ling Wei , Yu Wen Xi , Yu Gang
Published: October 2011

Desulfurization and Denitrification processes in two pulsed discharge plasma systems (NO/SO2/N2/O2/H2O and NO/SOSubscript text2/NSubscript text2/OSubscript text2) were simulated respectively, and then the removal characteristics of these two gas systems were analyzed. The results show that NO can be completely removed when the residence time is close to 1.3 s and SOSubscript text2 removal rate is 61.5% when the residence time reaches 3 s in a system containing water vapor (HSubscript text2O). When the system does not contain water vapor, NO removal rate is still much high, but SOSubscript text2 removal rate is approximately zero. When OSubscript text2 concentration is increased, NO removal velocity will be faster and the peak of the concentration curve of NOSubscript text2 will be higher. NO removing velocity is much faster in a system containing water vapor than that in a system without water vapor when both systems have almost the same OSubscript text2 concentration.
Kinetics for Sulfate Removal in Tannery Wastewater by Immobilized Activated Sludge
Authors: Zhao Chang Qing , Yang Qin Huan , Chen Wu Yong
Published: October 2011

The anaerobic activated sludge inoculated with an isolated SRB was immobilized on the granular activated carbon and the kinetics for the immobilized anaerobic sludge treating the sulfate in tannery wastewater was studied. Also, the aerobic activated sludge containing enriched SOB was immobilized and the kinetics for the sulfur conversion was studied with the immobilized aerobic sludge through treating sulfide (the reduction product of SO42-) in tannery wastewater. The results showed that the kinetics for treating SO42- with the immobilized SRB in the actual tannery wastewater could be expressed as follows: lnC =-0.04941 t+6.79764. The kinetics for the sulfur conversion with the immobilized SOB through treating the sulfide in the actual tannery wastewater could be expressed as follows: lnC =0.01109 t+3.09996. The established dynamic equations could predict the capacity of sulfate removal and sulfur conversion in tannery wastewater.
Experimental Study of Breakthrough Adsorption on Activated Carbon for CO2 Capture
Authors: Cen Qi Gang , Fang Meng Xiang , Xu Jia Ping , Luo Zhong Yang
Published: October 2011

In this study, a commercial activated carbon was assessed as adsorbent for post-combustion CO2 capture. The breakthrough adsorption experiments were conducted in a fixed-bed column with simulated flue gas of 12% CO2. The effects of feed flow rate and adsorption pressure on breakthrough time and CO2 adsorption capacity were evaluated. The column efficiency was introduced to estimate the percentage of the utilization of the bed adsorbent capacity. At a higher flow rate, the breakthrough time, breakthrough capacity and column efficiency decreased. Conversely, increasing adsorption pressure was favorable to CO2 adsorption by the increase in breakthrough time, CO2 adsorption capacity and the column efficiency. During the experiments, temperature changes were detected at three positions inside the column to track the movement of breakthrough front.
Studies on Effects of Several Wetland Plants on Eutrophic Water Purification
Authors: Peng Wan Ting , Zou Lin , Wang Jin , Pan Yuan Zhi
Published: October 2011

Effectiveness of combinations of seven different ecotypes of wetland plants including Thalia dealbata, Iris tectorum, Acorus calamus,Zizania aquatica, Nymphaea tetragona,Georgi, Myriophyllum aquaticum, Thalia dealbata purifying water was investigated by hydrostatic simulation experiment method. The research showed that combinations of various wetland plants had significant purification effects on eutrophic water body, plant community was stable, and plants grew well. Chemical Oxygen Demand (COD) removal efficiencies of various combinations were higher than 97%, and 25.9% higher than that of the blank control group; the average highest total phosphorus (TP) removal efficiency of plant combinations was 97.6%. Compared with COD and TP, Total nitrogen( TN)removal efficiency was lower, ranging from 90.4% to 83.1%.Different wetland plants had different purification effectiveness for different pollutant. The combination N+Z+A+ZI had the highest TNremoval efficiency, reaching 90.4%. Combinations N+Z+A+ZI and N+Z respectively won the first and second place in the disposal of TP,reaching 99.68%, 99.34%. For Chemical Oxygen Demand COD removal, the combination N+Z+C+T did the best and the highest removal efficiency reached 97.6%. Fuzzy comprehensive evaluation method is used to select the following combinations with stronger capacities of removing N and P in sewage: N+Z+A+ZI, N+Z, N+Z+C+T. They can be promoted and applied in purification of eutrophic water body in ecological projects.
Nickel Induced Oxidative Stress and the Responses of SOD Isoenzymes in Microcystis aeruginosa FACHB-905
Authors: Huang Li Juan , Chang Xue Xiu , Wu Cheng
Published: October 2011

The laboratory experiment was conducted to investigated the effect of nickel over a concentration gradient of 0.1~1.00 mg/L on biomass ( indicated by absorbance of cell culture at 663nm wavelength ), superoxide anion (O2•ˉ), malondialdehyde (MDA), and superoxide dismutase (SOD) in the cyanobacterium Microcystis aeruginosa FACHB 905 isolated from Dianchi Lake, south west of China . The results showed: (1) M. aeruginosa could live normally in Ni (II)-absence culture medium，but 0.3 mg/L Ni(II) was the fittest concentration for test M. aeruginosa, in which biomass and SOD activity were highest among all test cultures; (2) Ni(II) induced O2•ˉ and MDA in M. aeruginosa cells under the experimental condition, showing that Ni(II) could influence on M. aeruginosa by inducing oxidative stress; (3) Fe-SOD and Mn-SOD were found in M. aeruginosa and both of them were induced by lower Ni(II) but inhibited by higher concentration. The multiformity of SOD isoenzymes enhance the resistance of M. aeruginosa to oxygen stress induced by unfavorable condition, which explained that M. aeruginosa is the preponderant species in badly polluted Dianchi Lake water for long period.
Development Status of Lignite Quality Improvement Technology
Authors: Wen Wu Qi , Jin Shi Ping , Huang Su Yi , Fang Shun Li , Zhang Xi Lai , Pei Qing Long , Gao Bao Yu , Li Zhe
Published: October 2011

China has rich lignite resource, which has high moisture, low calorific value, short ignition period, etc. These characters limit lignite large-scale processing, utilization and transport also become difficult.Therefore, under our country's coal-dominated energy structure, lignite quality improvement technology can enhance the development and application for optimizing the energy structure. This paper will also introduce the development status of lignite quality improvement technology at home and abroad, and then give some insights for the future using of lignite.
Drawdown Cone Volume of Pumping Well in Non-Leaky Confined Aquifer
Authors: Yang Jian Min , Han Jun Jie
Published: October 2011

Drawdown cone volume of pumping well reflects the hydro geological conditions of aquifer, such as hydraulic parameters and elastic storage for confined aquifer. During later period of pumping test in non-leaky confined aquifer, the relationship between drawdown and distance appears as straight line in plots figure, and the relationship between drawdown and time appears as straight line in plots figure. Based on Theis solution, through analyzing of the slope of curves , and integrating, volume of drawdown cone of pumping well in non-leaky confined aquifer was derived in this paper.
A Study on Water Resources Carrying Capacity in Liaohe River Basin
Authors: Zhang Jing , He Jun Shi
Published: October 2011

Based on the investigation of water resources carrying capacity connotation, the parameter of water resources carrying capacity calculation model provided by predecessors is modified. The modified model is applied to analyze the water resources carrying capacity of Liaohe River basin in base year and planning years under different water quantity guarantee ratios. The results show that among the water resources subzones of Liaohe River basin, the water resources carrying capacity in Up Liuhekou and Down Liuhekou is amendatory, while it is worse in Hunhe and Taizihe-Daliaohe Main River. In wet year, all the subzones can carry while in other years the carrying capacity is different.