Removal Effect of Nitrifying Bacteria on Ammonia Nitrogen in Water

[Objectives]To investigate the removal effect of nitrifying bacteria on ammonia nitrogen in water.[Methods]In this experiment,the treated water(referred to as raw water hereinafter)from the Changping Town Qiaoli Water Treatment Project in Dongguan City of Guangdong Province was used as the experimental water body,and the nitrifying bacteria liquid used in the project was taken as the experimental material,to explore the removal effect of the nitrifying bacteria liquid on the ammonia nitrogen in the water body.[Results]Under the condition that other variables remain unchanged,the more the amount of nitrifying bacteria liquid added,the higher the removal efficiency of nitrifying bacteria liquid;under the same conditions,the removal effect of ammonia nitrogen in a stirred water body is better than that in an unstirred water body;the removal effect of ammonia nitrogen in a water body with bio-media/carriers is better than that without bio-media/carriers.[Conclusions]Nitrifying bacteria have a better removal effect on the ammonia nitrogen in the water body.

Scale effect removal and range migration correction for hypersonic target coherent detection

The detection of hypersonic targets usually confronts range migration(RM)issue before coherent integration(CI).The traditional methods aiming at correcting RM to obtain CI mainly considers the narrow-band radar condition.However,with the increasing requirement of far-range detection,the time bandwidth product,which is corresponding to radar’s mean power,should be promoted in actual application.Thus,the echo signal generates the scale effect(SE)at large time bandwidth product situation,influencing the intra and inter pulse integration performance.To eliminate SE and correct RM,this paper proposes an effective algorithm,i.e.,scaled location rotation transform(ScLRT).The ScLRT can remove SE to obtain the matching pulse compression(PC)as well as correct RM to complete CI via the location rotation transform,being implemented by seeking the actual rotation angle.Compared to the traditional coherent detection algorithms,Sc LRT can address the SE problem to achieve better detection/estimation capabilities.At last,this paper gives several simulations to assess the viability of ScLRT.

Influence Factors of Phosphorus Removal by Chemical Method in Sewage Treatment System

[Objective] The research aimed to study influence factors of phosphorus removal by chemical method in sewage treatment system. [ Method] In different reaction systems, removal effect of the phosphorus in sewage by dosing lime and influence of the constraint factor were stud- ied. [ Result] Lime precipitation method treating high-concentration phosphorus wastewater could not only decline cost of phosphorus removal by chemical method, but also reach better treatment effect under suitable stirring and precipitation conditions by controlling alkalinity and pH. Phosphor- us content of chemical sludge after treatment could reach 9% -12%, with higher recyclable value. E Conclusion] Lime method treating phosphorus- rich sewage was more economic than low-concentration phosphorus sewage, and had very great potential for recycling phosphorus.

Experimental Research about Denitrification by Box Filler Enhancing MBR Process

[Objective] The reseamh aimed to study removal effects of the organic matter and N by box filler enhancing MBR process. [ Method] By adding box filler into reaction pool of the MBR to treat domestic sewage, removal effects of the organic matter and N by box filler enhancing MBR process were studied. [ Result] COD means in effluent were respectively 26.8 and 24.7 mg/L without and with adding filler. Average removal rates of the NH3-N were respectively 98.44% and 96.37% with and without dosing filler, while average removal rates of the TN were 24.03% and 16.43%, respectively. COD and NH3-N concentrations in effluent were lower than Level-one A cdteda of Discharge Standard of the Pollutant for Municipal Wastewater Treatment Plant （ GB18918 -2002）. NO3^ -N was main existence form of the TN in effluent and occupied 98.06%, while NH3- N and NO2^--N only accounted for.1.22% and 0.72%. Further suggestion for denitrification study was as below. Firstly, the proportion of box filler on volume of the reaction cell should increase to 4% -5%. Secondly, single smaller filler with larger amount of internal fiber ought to be replaced. Thirdly, aeration amount needed to be decreased to right value, making that DO of the MBR reaction cell reduced to 1.5 -3.0 mg/L. [ Conclusion] The research provided theoretical basis for future engineering practice.

Fluoride removal by Al,Ti,and Fe hydroxides and coexisting ion effect

Batch experiments were conducted to evaluate fluoride removal by Al,Fe,and Ti-based coagulants and adsorbents,as well as the effects of coexisting ions and formation of aluminum–fluoride complexes on fluoride removal by co-precipitation with alum（Al_2（SO_4）_3·18H_2O）.Aluminum sulfate was more efficient than the other coagulants for fluoride removal in the pH range between 6 and 8.Nano-crystalline TiO_2 was more effective for fluoride removal than Al and Fe hydroxides in a pH range of 3–5.Coexisting anions in water decreased the removal of fluoride in the order：phosphate（2.5 mg/L） 〉 arsenate（0.1 mg/L） 〉 bicarbonate（200 mg/L） 〉sulfate（100 mg/L） = nitrate（100 mg/L） 〉 silicate（10 mg/L） at a pH of 6.0.The effect of silicate became more significant at pH 〉 7.0.Calcium and magnesium improved the removal of fluoride.Zeta-potential measurements determined that the adsorption of fluoride shifted the PZC of Al（OH）_3 precipitates from 8.9 to 8.4,indicating the chemical adsorption of fluoride at the surface.The presence of fluoride in solution significantly increased the soluble aluminum concentration at pH 〈 6.5.A Visual MINTEQ modeling study indicated that the increased aluminum solubility was caused by the formation of AlF^（2＋）,AlF^（＋2）,and AlF_3complexes.The AlF_x complexes decreased the removal of fluoride during co-precipitation with aluminum sulfate.

Spatial-temporal variability of snow cover over the Amur River Basin inferred from MODIS daily snow products in recent decades

MODIS snow products MOD10A1\MYD10A1 provided us a unique chance to investigate snow cover as well as its spatial-temporal variability in response to global changes from regional and global perspectives.By means of MODIS snow products MOD10A1\MYD10A1 derived from an extensive area of the Amur River Basin,mainly located in the Northeast part of China,some part in far east area of the former USSR and a minor part in Republic of Mongolia,the reproduced snow datasets after removal of cloud effects covering the whole watershed of the Amur River Basin were generated by using 6 different cloud-effect-removing algorithms.The accuracy of the reproduced snow products was evaluated with the time series of snow depth data observed from 2002 to 2010 within the Chinese part of the basin,and the results suggested that the accuracies for the reproduced monthly mean snow depth datasets derived from 6 different cloud-effect-removing algorithms varied from 82%to 96%,the snow classification accuracies(the harmonic mean of Recall and Precision)was higher than 80%,close to the accuracy of the original snow product under clear sky conditions when snow cover was stably accumulated.By using the reproduced snow product dataset with the best validated cloud-effect-removing algorithm newly proposed,spatial-temporal variability of snow coverage fraction(SCF),the date when snow cover started to accumulate(SCS)as well as the date when being melted off(SCM)in the Amur River Basin from 2002 to 2016 were investigated.The results indicated that the SCF characterized the significant spatial heterogeneity tended to be higher towards East and North but lower toward West and South over the Amur River Basin.The inter-annual variations of SCF showed an insignificant increase in general with slight fluctuations in majority part of the basin.Both SCS and SCM tended to be slightly linear varied and the inter-annual differences were obvious.In addition,a clear decreasing trend in snow cover is observed in the region.Trend analysis(at 10%significance level)showed that 71%of areas between 2,000 and 2,380 m a.s.l.experienced a reduction in duration and coverage of annual snow cover.Moreover,a severe snow cover reduction during recent years with sharp fluctuations was investigated.Overall spatial-temporal variability of Both SCS and SCM tended to coincide with that of SCF over the basin in general.

Effect of Removing Toxic Substances Combined with Activating Blood Circulation on Stabilizing the Atherosclerotic Plaque and Unstable Angina

The therapeutic effects of activating blood circulation to remove stasis of Chinese medicine （CM） in the prevention and treatment of atherosclerotic diseases such as coronary artery disease and angina are generally acknowledged. In recent years, to further improve the therapeutic effects of those Chinese herbs on such diseases, we have carried out a series of studies of CM medications with the function of clearing heat and removing toxic substances combined with activating blood circulation to remove stasis.

A novel stability prediction approach for thin-walled component milling considering material removing process

The milling stability of thin-walled components is an important issue in the aviation manufacturing industry, which greatly limits the removal rate of a workpiece. However, for a thin-walled workpiece, the dynamic characteristics vary at different positions. In addition, the removed part also has influence on determining the modal parameters of the workpiece. Thus,the milling stability is also time-variant. In this work, in order to investigate the time variation of a workpiece＇s dynamic characteristics, a new computational model is firstly derived by dividing the workpiece into a removed part and a remaining part with the Ritz method. Then, an updated frequency response function is obtained by Lagrange＇s equation and the corresponding modal parameters are extracted. Finally, multi-mode stability lobes are plotted by the different quadrature method and its accuracy is verified by experiments. The proposed method improves the computational efficiency to predict the time-varying characteristics of a thin-walled workpiece.