Nitrogen removal for low-carbon wastewater in reversed A^2/O process by regulation technology

Full scale experimental study on nitrogen removal for low-carbon wastewater was conducted in reversed A2/O process in Jiguanshi waste water treatment plant in Chongqing,in order to aid the operation and maintenance of similar WWTP. When the proposed measures,such as using 0.1% (volume fraction of wastewater) landfill leachate,shortening HRT by 2/3 in the primary sedimentation tank and controlling DO at 0.5 mg/L in the 3rd section of aerobic zone,are applied,15% of the carbon source can be complemented,the favorable property of activated sludge is achieved,and the nitrogen removal effect is significantly improved. The effluent NH3-N is 2 mg/L and the removal rate is 90%. The effluent TN is 17 mg/L and the removal rate is 54%. The up-to-standard discharge of the effluent is achieved. And after the optimization,the unit electricity consumption also reaches 0.21 kW/h and saves 20%.

APPLICATION OF GREY SYSTEM THEORY TO PROCESSING OF MEASURING DATA IN REVERSE ENGINEERING

The processing of measuri ng data plays an important role in reverse engineering. Based on grey system the ory, we first propose some methods to the processing of measuring data in revers e engineering. The measured data usually have some abnormalities. When the abnor mal data are eliminated by filtering, blanks are created. The grey generation an d GM(1,1) are used to create new data for these blanks. For the uneven data sequ en ce created by measuring error, the mean generation is used to smooth it and then the stepwise and smooth generations are used to improve the data sequence.

Spatial heterogeneity of soil water content in the reversion process of desertification in arid areas

Sandy soils in arid,rain-fed environments have low and limited water content,which is a principal factor limiting vegetation development,and a key constraint controlling the structure and functions of the ecological systems in arid areas.The spatial heterogeneity of soil water content is a major soil property,and a focus of soil science and hydrology.On the southern edge of the Tengger Desert,sample plots were selected from mobile sand dunes in desertified lands that had been enclosed for 5,15 and 25 years,respectively.This study explored the dynamic and spatial heterogeneity of soil water content in these different layers of soil that were also in the reversion process of desertification.The results showed that the soil water content of the mobile sand dunes was highest when in the initial stages of the reversion process of desertification,while the soil water content in the 0-20 cm,20-40 cm and 40-60 cm layers of soil was 1.769%,3.011%,and 2.967% respectively,presenting a restoring tendency after 25 years of enclosure.There were significant differences,as a whole,in the soil water content among different restoration stages and different soil layers,respectively.Changes in soil water content,in different soil layers,at different restoration stages,exhibited exponential or spherical patterns.The spatial distribution of soil water content exhibited a mosaic patch pattern with obvious spatial heterogeneity.The ratio of the heterogeneity of spatial autocorrelation to gross spatial heterogeneity was greater than 50%.The gross spatial heterogeneity of the 0-20 cm layer of soil improved gradually,while those of the 20-40 cm and 40-60 cm layers improved initially,then weakened in the reversion process of desertification.This study revealed that restoration with sand-binding vegetation reduced soil water content,and increased its spatial heterogeneity in arid areas.However,after 25 years of vegetation-soil system restoration,the soil water content started to increase and its spatial heterogeneity started to weaken.These results will further benefit the understanding of the ecological mechanism between soil water and sand-binding vegetation.

Research on Technological Process Control Model of Reverse Logistics in Manufacturing System

This paper has found out some important input factors of reverse logistics in manufacturing system throuth analysis and summary,and established four kinds of technological process control models of reverse logistics in manufacturing system according to different processing methods. These models embed each other that form a cubic control system of reverse logistics.

Geometrical Reconstruction and CNC Process of Spurious Tympanic Membrane Based on Reverse Engineering

Perforation of tympanic membrane is one of the main reasons for both deafness and dyssaudia.We could improve and restore audition by restoring or replacing the tympanic membrane.So,whether you can make the spurious tympanic membrane successfully is one of the keys to a successful operation.Utilizing CMM (Coordinate Measuring Machine) measurement equipment, we measured tympanic membrane model precisely and digitally.We also analysed the measured data by point to surface and we have successfully reconstructed the CAD model of the spurious tympanic membrane.Using the model we have got,we schemed out the mold of spurious tympanic membrane.In addition,we utilized MasterCAM compiling CNC (Computerized Numerical Con- trol) code and simulating the course of working.Ultimately,we obtained the mold of spurious tympanic membrane.Our research in this article has great significance to the success of spurious tympanic membrane grafting operation.

Investigation of magnetization reversal process in pinned CoFeB thin film by in-situ Lorentz TEM

Exchange bias effect has been widely employed for various magnetic devices.The experimentally reported magnitude of exchange bias field is often smaller than that predicted theoretically,which is considered to be due to the partly pinned spins of ferromagnetic layer by antiferromagnetic layer.However,mapping the distribution of pinned spins is challenging.In this work,we directly image the reverse domain nucleation and domain wall movement process in the exchange biased Co Fe B/Ir Mn bilayers by Lorentz transmission electron microscopy.From the in-situ experiments,we obtain the distribution mapping of the pinning strength,showing that only 1/6 of the ferromagnetic layer at the interface is strongly pinned by the antiferromagnetic layer.Our results prove the existence of an inhomogeneous pinning effect in exchange bias systems.

Reversal process of the South China Sea western boundary current in autumn 2011

Using merged sea level anomaly and absolute geostrophic velocity products from satellite altimetry and Argos drifter data, we analyzed the reversal process of the South China Sea （SCS） westem boundary current （SCSwbc） from a summer to winter pattern in 2011 and important oceanic phenomena during this process. Results show that the outbreak time of the northeast monsoon over the southern SCS lagged that over the northern SCS by about 1 month. During the SCS monsoon reversal period, the SCSwbc reversed rapidly into the winter pattern at the Guangdong continental slope in late September. Subsequently, the southward Vietnam coastal boundary current strengthened. However, the northward Natuna Current maintained a summer state until mid-October. Thus, the balance between the southward and northward currents was lost when they met, their junction moved gradually southward. However, a loop current formed southeast of Vietnam because the main stream of the Vietnam Offshore Current （VOC） remained near its original latitude, Meanwhile, the VOC and associated dipole circulation system strengthened. After mid- October, the northward Natuna Current began to weaken, the loop current finally shed, becoming a cool ring. The VOC and its associated dipole sub-basin circulation system also weakened gradually until it disappeared.

Magnetization Reversal Process of Single Crystal a-Fe Containing a Nonmagnetic Particle

The magnetization reversal process and hysteresis loops in a single crystal α-iron with nonmagnetic particles are simulated in this work based on the Landau-Lifshitz-Gilbert equation. The evolutions of the magnetic domain morphology are studied, and our analyses show that the magnetization reversal process is affected by the interaction between the moving domain wall and the existing nonmagnetic particles. This interaction strongly depends on the size of the particles, and it is found that particles with a particular size contribute the most to magnetic hardening.

Symmetry Violation of Time Reversal in Third Order Vertex Angle Renormalization Process of Electromagnetic Interaction

According to the current understanding, electromagnetic interaction is invariable under time reversal. However, the proof of time reversal symmetry in quantum theory of field has not considered the effects of high order perturbation normalizations. It is proved in the paper that when the renormalization effect of third order vertex angles process is taken into account, the symmetry of time reversal will be violated in electromagnetic interaction process. Because the magnitude order of symmetry violation is about 10–5, but the precision of current experiments on time reversal in particle physics is about 10–3, this kind of symmetry violation can not be found. The result reveals the micro-origin of asymmetry of time reversal and can be used to solve the famous irreversibility paradox in the evolution processes of macro- material systems.

Polymerization of o-Phenylenediamine Catalyzed byHemeproteins Encapsulated in Reversed Micelle

Hemeproteins encapsulated in reversed micelle formulated with di-2-ethylhexyl sulfosuccinate(AOT) was found to catalyze the polymerization of o-phenylenediamine(o-PDA) with hydrogen peroxide, whereas o-PDA catalyzed by hemeproteins dissolved in water could only form its trimers. As the nanostructural environment in reversed micelle acts as a certain orientation surrounding medium, it offers a strong electrostatic field that alters the reductive potential of Fe 3+/Fe 2+(E m7) in the heme of hemeproteins and thus increases the catalytic activity of peroxidase accordingly. According to the results of UV-Vis, 1H NMR and FTIR, the polymer catalyzed by hemoglobin(Hb) in reversed micelle was presumed to be constructed of lines and trapeziforms alternatively.

Mechanisms and Processes Leading to Reverse Zoning in the Andong Granitoid Pluton, Andong Batholith, Korea

The Andong pluton consists of comagmatic granitoid rocks which constitute outstanding examples of reversely zoned granitoids. The pluton has three lithofacies: hornblende biotite tonalite, biotite granodiorite and porphyritic biotite granite. The zoned pattern forms by locating a tonalite core containing high-temperature mafic assemblages in central part,granodiorite rims in marginal part, and a porphyritic granite cap containing more felsic assemblages in topside of the pluton.Mineral abundances as well as bulk compositions of the granitoids indicate that the interior is enriched in mafic minerals and that it shows higher contents of oxides than the margin and topside. The compositional gradients change gradually with continuity between the lithofacies. The regular compositional variations within the pluton support the argument that the pluton behaved as an individual petrochemical system. Model abundances of the granitoids are in agreement with the bulk compositional gradients, suggesting that no significant interaction with country rocks occurred. Remobilization (resurgence) of deeper parts of the system into the more felsic magmas of the chamber explains the reverse zoning. Fractional crystallization was of importance and probably accounts for the selective removal of the settling phases. The Andong pluton is an example of reversely zoned plutons related by remobilization of more mafic but consanguineous magmas. Large-scale upwelling occurred in the pluton leading to the present arrangement of three lithofacies. It is conceivable that remnants of the reverse zoning become more difficult to discern as the plutonic rocks reach the latest stages of their evolution. In this case, the Andong pluton represents an earlier stage in the evolution of a felsic system that is usually represented by the final stages in normally zoned plutons.

基于OBE理念的农业信息数智化处理研究

基于OBE理念,设计了农业信息系统。首先,基于ZigBee技术设计传感器网络,传感器检测数据通过ZigBee网络和运营商基站上传到农田信息服务器,对同类传感器数据进行融合后,得到同类传感器数据表征值;然后,对6类传感器的表征值进行融合,得到农田环境综合评估结果。设计微信小程序,显示农田中6类传感器的表征值,进而显示农田环境综合评估结果。对传感器上传数据可靠性进行测试,与实地测试对比,误差区间为[0,0.3℃];对微信小程序显示效果进行验证,小程序可以清晰地将农田环境综合评估结果展示给用户。

多功能A2O与水平潜流湿地在高寒地区的联合应用设计研究

针对高寒地区冬季采用A^(2)O(厌氧-缺氧-好氧)工艺+水平潜流人工湿地联合处理生活污水出水中的氮、磷可能存在超标和污水水质多变等问题,对传统的A^(2)O工艺、水平潜流人工湿地结构进行创新性改进设计:A^(2)O工艺采用厌氧池、缺氧池、好氧池环绕在圆形竖流沉淀池外围,呈环状布置,减少污水热量损失、改善水力条件、提高微生物活性;厌氧池、缺氧池增设曝气工艺,实现ANO(缺氧-好氧)工艺、APO(厌氧-好氧)工艺、A^(2)O工艺可调式功能;O(好氧)工艺中添加悬浮填料,增加单位池容微生物含量,提高有机物、氮、磷等去除率。人工湿地通过试验优选高效除磷填料、根系发达植被根系深入低水位、填料正反粒度双级配布设,提高了氮、磷去除率和悬浮物截留率;人工湿地低水位进出水可提高冬季池内污水温度。结果表明,强化后的工艺系统不同工况下的实际运行效果达到了预期目标。

Comparative study of two biological nitrogen removal processes:A/O process and step-feeding process

Two biological nitrogen removal processes are compared in the aspect of nitrogen removal, process operation and energy saving. Results show that when the returned sludge ratio is 50% of the inflow rate, the step-feeding process achieves over 80% total nitrogen （TN） removal efficiency, but the TN removal efficiency of the A/O process is only 40%. Moreover, filamentous sludge bulking can be well restrained in the step-feeding process. Given the conditions of a returned sludge ratio of 100% and a nitrifying liquor recycle ratio of 200%, the TN removal efficiency is 78.32% in the A/O process, but the sludge volume index （SVI） value increases to 143 mL/g. In the step-feeding process, the SVI is only 94.4 mL/g when the TN removal efficiency reaches 81. 1%. The step-feeding process has distinct advantages over the A/O process in the aspects of practicability, nitrogen removal and operating stability.

Hot deformation and processing maps of Al_2O_3/Al composites fabricated by flake powder metallurgy

The deformation behaviors of Al2O3/Al composites were investigated by compressive tests conducted at temperature of 300-450 °C and strain rates of 0.001-1.0 s-1 with Gleeble-1500 D thermal simulator system. The results show that the flow stress increases with increasing strain rate and decreasing temperature. The hyperbolic sine constitutive equation can describe the flow stress behavior of Al2O3/Al composites, and the deformation activation energy and constitutive equations were calculated. The processing maps of Al2O3/Al-2 μm and Al2O3/Al-1 μm composites at strain of 0.6 were obtained and the optimum processing domains are in ranges of 300-330 °C, 0.007-0.03 s-1 and 335-360 °C, 0.015-0.06 s-1 for hot working, respectively. The instability zones of flow behavior can also be recognized by the maps.

Influence of pretreatment process on structure, morphology and electrochemical properties of Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_2 cathode material

The layered Li[Ni1/3Mn1/3Co1/3]O2 was separately synthesized by pretreatment process of ball mill method and solution phase route, using [Ni1/3Co1/3Mn1/3]3O4 and lithium hydroxide as raw materials. The physical and electrochemical behaviors of Li[Ni1/3Mn1/3Co1/3]O2 were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, field emission scanning electron microscopy （FESEM） and electrochemical charge/discharge cycling tests. The results show that the difference in pretreatment process results in the difference in compound Li[Ni1/3Co1/3Mn1/3]O2 structure, morphology and the electrochemical characteristics. The Li[Ni1/3Mn1/3Co1/3]O2 prepared by solution phase route maintains the uniform spherical morphology of the [Ni1/3Co1/3Mn1/3]3O4, and it exhibits a higher capacity retention and better rate capability than that prepared by ball mill method. The initial discharge capacity of this sample reaches 178 mA-h/g and the capacity retention after 50 cycles is 98.7% at a current density of 20 mA/g. Moreover, it delivers high discharge capacity of 135 mA-h/g at a current density of 1 000 mA/g.

Study on Limited Filamentous Sludge Bulking Test in A/O Activated Sludge Process

[Objective] This study aimed to make use of the limited filamentous sludge bulking characteristics to purify water quality and save energy. [Method] The effects of dissolved oxygen （DO） on sludge bulking were explored by changing the DO con- centration in the aerobiotic pool of NO system from the low load （0.25 kg COD/（kg MLSS.d）） and the medium to high load （0.55 kgCOD/（kg MLSSod））. [Result] In the NO activated sludge system, when the sludge load was 0.25 kg COD/（kg MLSS.d）, DO=1.5 mg/L, the sludge index was at around 250, while when the sludge load- ing was 0.55 kg COD/（kg MLSS.d）, DO=1.5 mg/L, the sludge index was close to 300, occurring the limited filamentous bulking. The bulked sludge still showed high removal rates to COD, SS, nitrogen and phosphorus. [Conclusion] It could improve the oxygen transfer rate and reduce the aeration rate at low DO conditions to achieve energy-saving.

Nitrogen removal influence factors in A/O process and decision trees for nitrification/denitrification system

In order to improve nitrogen removal in anoxic/oxic(A/O) process effectively for treating domestic wastewaters, the influence factors, DO(dissolved oxygen), nitrate recirculation, sludge recycle, SRT(solids residence time), influent COD/TN and HRT(hydraulic retention time) were studied. Results indicated that it was possible to increase nitrogen removal by using corresponding control strategies, such as, adjusting the DO set point according to effluent ammonia concentration; manipulating nitrate recirculation flow according to nitrate concentration at the end of anoxic zone. Based on the experiments results, a knowledge-based approach for supervision of the nitrogen removal problems was considered, and decision trees for diagnosing nitrification and denitrification problems were built and successfully applied to A/O process.

Toxicity Reduction of Municipal Wastewater by Anaerobic-anoxic-oxic Process

Objective This study was conducted to optimize the operational parameters of anaerobic-anoxic-oxic （A^2/O） processes to reduce the toxicity of municipal wastewater and evaluate its ability to reduce toxicity. Methods A luminescent bacterium toxicity bioassay was employed to assess the toxicity of influent and effluent of each reactor in the A2/O system. Results The optimum operational parameters for toxicity reduction were as follows： anaerobic hydraulic retention time （HRT） = 2.8 h, anoxic HRT = 2.8 h, aerobic HRT = 6.9 h, sludge retention time （SRT） = 15 days and internal recycle ratio （IRR） = 100%. An important toxicity reduction （%） was observed in the optimized A2/O process, even when the toluene concentration of the influent was 120.7 mg·L^-1. Conclusions The toxicity of municipal wastewater was reduced significantly during the A^2/O process. A^2/O process can be used for toxicity reduction of municipal wastewater under toxic-shock loading.

FINITE ELEMENT NUMERICAL SIMULATION OF TEMPERATURE FIELD IN METAL PATTERN CASTING SYSTEM AND "REVERSE METHOD" OF DEFINING THE THERMAL PHYSICAL COEFFICIENT

With the technology support of virtual reality and ANSYS software, an example on the simulation of temperature distribution of casting system during the solidification process was provided, which took the latent heat of phase change, the conditions for convection, and the interface heat transfer coefficient into consideration. The result of ANSYS was found to agree well with the test data. This research offers an unorthodox way or ＂reverse method＂ of defining the relevant thermal physical coefficient.