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Feasibility of an innovative integrated process of simultaneous desulfurization and denitrification
An anaerobic expanding-bed reactor was adopted to investigate the feasibility of an innovative inte-grated process of simultaneous desulfurization and denitrification (SDD) for high strength wastewater. In the re-actor, beterotrophic bacteria (including sulfate reducing bacterium and denitrifying bacteria) and autotrophic bacteria (including Thiobacillus denitrificans) cooperated together by incubating and enriching functional bac-teria on different carriers in the anaerobic activated sludge. Synthetic wastewater with high concentrations of sul-fate and nitrate was employed. The experimental results showed that the removal efficiency of sulfate and nitrate was above 85%, elemental sulfur was observed while nitrate was absent in effluent. The balance of sulfur, ni-trogen and electron was discussed respectively, which indicated that the integrated SDD process could be actual-ized. These results might provide a guidance to further investigate the key factors affecting the integrated SDD process and to improve the efficiency of desulfurization and denitrification in wastewater treatment....
2020-11-11 22:33:38浏览：73
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Hierarchical Colored Timed Petri Nets for Maintenance Process Modeling of Civil Aircraft
Civil aircraft maintenance process simulation model is an effective method for analyzing the maintainability of a civil aircraft. First, we present the Hierarchical Colored Timed Petri Nets for maintenance process modeling of civil aircraft. Then, we expound a general method of civil aircraft maintenance activities, determine the maintenance level for decomposition, and propose the methods of describing logic of relations between the maintenance activities based on Petri Net. Finally, a time Colored Petri multi-level network modeling and simulation procedures and steps are given with the maintenance example of the landing gear burst tire of a certain type of aircraft. The feasibility of the method is proved by the example....
2020-11-11 22:33:38浏览：71
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Modeling of CVI process in fabrication of carbon/carbon composites by an artificial neural network
The chemical vapor infiltration(CVI) process in fabrication of carbon-carbon composites is very complex and highly inefficient, which adds considerably to the cost of fabrication and limits the application of the material. This paper tries to use a supervised artificial neural network(ANN) to model the nonlinear relationship between parameters of isothermal CVI(ICVI) processes and physical properties of C/C composites. A model for preprocessing dataset and selecting its topology is developed using the Levenberg-Marquardt training algorithm and trained with comprehensive dataset of tubal C/C components collected from experimental data and abundant simulated data obtained by the finite element method. A basic repository on the domain knowledge of CVI processes is established via sufficient data mining by the network. With the help of the repository stored in the trained network, not only the time-dependent effects of parameters in CVI processes but also their coupling effects can be analyzed and predicted. The results show that the ANN system is effective and successful for optimizing CVI processes in fabrication of C/C composites....
2020-11-11 22:33:38浏览：52
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Research on Crucial Manufacturing Process of Rigid-Flex PCB
The main characteristics, applications, the emphases of manufacturing process are introduced, and the research of new product of rigid-flex Printed Circuit Board (PCB) is also described. In particular, the plasma desmear process, which is the crucial problems of manufacturing process, is discussed in detail. Samsung 4-layer rigid-flex PCB has been developed successfully, and the qualification rate reaches to 89.4%....
2020-11-11 22:33:38浏览：70
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Research on the controller of an arc welding process based on a PID neural network
A controller based on a PID neural network(PIDNN)is proposed for an arc welding power source whose output characteristic in responding to a given value is quickly and intelligently controlled in the welding process.The new method syncretizes the PID control strategy and neural network to control the welding process intelligently,so it has the merit of PID control rules and the trait of better information disposal ability of the neural network.The results of simulation show that the controller has the properties of quick response,low overshoot quick convergence and good stable accuracy,which meet the requirements for control of the welding process....
2020-11-11 22:33:38浏览：68
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Numerical simulation of mould filling process for pressure plate and valve handle in LFC
In lost foam casting (LFC),the distribution of polymer beads during the bead filling process is not uniform,and the collision between polymer beads determines the distribution of two-phase flow of gas and solid.The interaction between the gas and solid phases reveals as coupling effect of the force that gas exerts on particles or vice versa,or that among particles.The gas-solid flow in filling process is nonlinearity,which makes the coupling effect an essential point to carry out a simulation properly.Therefore,information of each particle's motion is important for acquiring the law of filling process.In bead filling process,compressed air is pressed into mold cavity,and discharged from gas vent,creating a pressure difference between outer and inner space near the gas vent.This pressure difference directly changes the spatial distribution and motion trace of gas and solid phases.In this paper,Discrete Element Method (DEM) and Computational Fluid Dynamics (CFD) are employed to simulate the fluid dynamic character based on Newton's Third Law of Motion.The simulation results of some casting products such as pressure plate and valve handle are compared with the result obtained from practical experiment in order to test the feasibility of DEM.The comparison shows that this DEM method can be a very promising tool in the mould filling simulation of beads' movement....
2020-11-11 22:33:38浏览：77
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Calculating Method for Influence of Material Flow on Energy Consumption in Steel Manufacturing Proce
From the viewpoint of systems energy conservation, the influences of material flow on its energy consumption in a steel manufacturing process is an important subject. The quantitative analysis of the relationship between material flow and the energy intensity is useful to save energy in steel industry. Based on the concept of standard material flow diagram, all possible situations of ferric material flow in steel manufacturing process are analyzed. The expressions of the influence of material flow deviated from standard material flow diagram on energy consumption are put forward....
2020-11-11 22:33:38浏览：67
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Dynamic analysis of a guided projectile during engraving process
The reliability of the electronic components inside a guided projectile is highly affected by the launch dynamics of guided projectile. The engraving process plays a crucial role on determining the ballistic performance and projectile stability. This paper analyzes the dynamic response of a guided projectile during the engraving process. By considering the projectile center of gravity moving during the engraving process, a dynamics model is established with the coupling of interior ballistic equations. The results detail the stress situation of a guided projectile band during its engraving process. Meanwhile, the axial dynamic response of projectile in the several milliseconds following the engraving process is also researched. To further explore how the different performance of the engraving band can affect the dynamics of guided projectile, this paper focuses on these two aspects:(a) the effects caused by the different band geometry;and (b) the effects caused by different band materials. The time domain and frequency domain responses show that the dynamics of the projectile are quite sensitive to the engraving band width. A material with a small modulus of elasticity is more stable than one with a high modulus of elasticity....
2020-11-11 22:33:38浏览：43
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Stoichiometric deduction of activated sludge process for organic carbon and nitrogen removal
The activated sludge process (ASP) is the most generally applied biological wastewater treatment method. The ASP for the removal of organic carbon and nitrogen can be looked as the combination of eight processes. In order to set up an ASP model, the stoichiometric coefficients should be deduced so that the stoichiometric matrix can be presented. The important assumptions and simplifications behind the model for ASP are enumerated. Using the matrix, mass balance equation and consistent units, the stoichiometric coefficients in the eight processes are exclusively deduced one by one....
2020-11-11 22:33:38浏览：78
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Review on Sol-Gel Derived Coatings:Process, Techniques and Optical Applications
Sol-gel process is one of the simplest techniques to manufacture thin films. The quality of the prepared films depends on the parameters of the sol-gel process and the used technique for deposition. A great variety of the sol-gel derived films have been prepared for different applications. We present a review on the sol-gel derived coatings. The description of the process is introduced in details. Different sol-gel deposition techniques are mentioned. The optical applications of the sol-gel derived coatings are reviewed....
2020-11-11 22:33:38浏览：57
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Comparative Process for the Preparation of 9-Oxime Erythromycin A
The comparative process for preparing 9-oxime erythromycin A (EMAO) is investigated. EMAO was synthesized and compared by the reaction of erythromycin and hydroxylamine hydrochloride with various bases such as sodium acetate, triethylamine, etc. A new synthetic method is established. The oximation is performed under dynamic buffer system; less degradation impurities are formed. The yield of EMAO reaches more than 95%, HPLC analysis shows that the purity of EMAO is more than 90%, and the E/Z isomeric ratio preponderates over 7∶1....
2020-11-11 22:33:38浏览：63
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On-line Batch Process Monitoring and Diagnosing Based on Fisher Discriminant Analysis
A new on-line batch process monitoring and diagnosing approach based on Fisher discriminant analysis (FDA) was proposed. This method does not need to predict the future observations of variables, so it is more sensitive to fault detection and stronger implement for monitoring. In order to improve the monitoring performance,the variables trajectories of batch process are separated into several blocks. The key to the proposed approach for on-line monitoring is to calculate the distance of block data that project to low-dimension Fisher space between new batch and reference batch. Comparing the distance with the predefine threshold, it can be considered whether the batch process is normal or abnormal. Fault diagnosis is performed based on the weights in fault direction calculated by FDA. The proposed method was applied to the simulation model of fed-batch penicillin fermentation and the results were compared with those obtained using MPCA. The simulation results clearly show that the on-line monitoring method based on FDA is more efficient than the MPCA....
2020-11-11 22:33:38浏览：60
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On-line temperature monitoring and process diagnosis of plasma sprayed coatings
On-line temperature monitoring of plasma sprayed coating is presented, which is based on IR pyrometery combined to robot trajectories. Temperature fields of the substrate before spraying and the deposited coating when the damage happens are taken to investigate the temperature fluctuation information. Experimental results demonstrate that coating damage always occurs in the temperature transition area of the substrate from the higher to the lower, as well as the higher temperature area. The temperature difference between the peak and the mean of the relevant regions is beyond 30-50 ℃ or even higher. This case provides the omen of coating damage and the focusing scopes for the process control of coating temperature in plasma spraying....
2020-11-11 22:33:38浏览：70
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Repair welding process of friction stir welding groove defect
The groove defect formed in the friction stir welding dramatically deteriorates weld appearances and mechanical properties of the joints owing to its larger size and penetration. Therefore, the friction stir repair welding was utilized to remove such a groove defect, and the focus was placed on the mechanical properties and microstructural characteristics of the repair joints so as to obtain an optimum repair welding process. The experimental results indicate that the groove defect can be removed by friction stir repair welding, and the offset repair welding process is superior to the symmetrical repair welding process. In the symmetrical repair welding process, a large number of fine cavity defects and an obvious aggregation of hard-brittle phase Al2Cu occur, accordingly the mechanical properties of the repair joint are weakened, and the fracture feature of repair joint is partially brittle and partially plastic. A good-quality repair joint can be obtained by the offset repair welding process, and the repair joint is fractured near the interface between the weld nugget zone and thermal-mechanically affected zone....
2020-11-11 22:33:38浏览：74
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Preparation of single-phase ammonium dimolybdate by combination process
A novel method for the preparation of single-phase ammonium dimolybdate with industrial ammonium molybdate was studied.Various influential factors were evaluated in the paper,including reaction temperature,reaction time,initial molybdenum concentration,initial NH3/Mo molar ratio,and stirring speed.Under the optimum experimental conditions,the crystallization rate of product is 85.23％.The X-ray diffraction (XRD) analysis and chemical analysis show that the product is single-phase ammonium dimolybdate,and no impurity phases exist.The scanning electronic microscope (SEM) image reveals uniform particle size,good particle dispersion,and no agglomeration between particles.Meanwhile,the final pH value of acidification was investigated.The total molybdenum recovery can reach up to 99.40％,and the main phases of acidification product are the same as those of raw material with the final pH value of 1.5.This determines that the acidification product can be used as a raw material to produce single-phase ammonium dimolybdate....
2020-11-11 22:33:38浏览：59
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