Anaerobic ammonia oxidation(Anammox)is an economical and sustainablewastewater nitrogen removal technology,and its application in the mainstream process is the inevitable trend of the development of ***,how to effecti...
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Anaerobic ammonia oxidation(Anammox)is an economical and sustainablewastewater nitrogen removal technology,and its application in the mainstream process is the inevitable trend of the development of ***,how to effectively enriching Anammox bacteria from the activated sludge remains challenging and restricts its extensive *** this study,the rapid and efficient enrichment of Anammox bacteriawas achieved by raising the reflux ratio and nitrogen loading rate(NLR)using conventional activated sludge as the *** the screening phase(days 1–90),the reflux ratio was increased to discharge partial floc sludge,resulting in the relative abundance of Candidatus Brocadiaceae increased from0.04%to 22.54%,which effectively reduced thematrix and spatial competition between other microorganisms and Anammox *** day 90,the stoichiometric ratio of the Anammox process closely approached the theoretical value of 1:1.32:0.26,indicating that the Anammox reaction was the primary nitrogen removal process in the *** the enrichment phase(days 91–238),the NLR increased from 0.43 to 1.20 kgN/(m^(3)·d)and removal efficiency was 71.89%,resulting in the relative abundance of Candidatus Brocadiaceae increased to 61.27%on day *** reactor operated steadily from days 444 to 498,maintaining the nitrogen removal rate(NRR)of 3.00 kgN/(m^(3)·d)and achieving successful sludge granulation with the particle size of 392.4μ*** short,this study provided a simple and efficient approach for enriching Anammox bacteria from the activated sludge,supporting to start an Anammox process efficiently.
It is important to analyze the damage evolution process of surrounding rock under different water content for the stability of engineering rock *** on digital speckle correlation(DSCM),acoustic emission(AE)and electro...
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It is important to analyze the damage evolution process of surrounding rock under different water content for the stability of engineering rock *** on digital speckle correlation(DSCM),acoustic emission(AE)and electromagnetic radiation(EMR),uniaxial hierarchical cyclic loading and unloading tests were carried out on sandstones with different fracture numbers under dry,natural and saturated water content,to explore the fracture propagation,failure precursor characteristics and damage response mechanism under the influence of water content *** results show that with the increase of water content,the peak stress and crack initiation stress decrease gradually,and the decreases are 15.28%-21.11%and 17.64%-23.04%,*** peak strain and crack initiation strain increase gradually,and the increases are 19.85%-44.53%and 19.15%-41.94%,*** precracked rock with different water content is mainly characterized by tensile failure at different loading ***,with the increase of water content,the proportion of shear cracks gradually increases,while acoustic emission events gradually decrease,the dissipative energy and energy storage limits of the rock under peak load gradually decrease,and the charge signal increases significantly,which is because the lubrication effect of water reduces the friction coefficient between crack surfaces.
The oxygen content of metal powder is decisive for the recyclability of *** research on the effect of oxygen content on powder properties and material formability has practical significance for economical production w...
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The oxygen content of metal powder is decisive for the recyclability of *** research on the effect of oxygen content on powder properties and material formability has practical significance for economical production with additive manufacturing while preventing the waste of ***,we deliberately oxidized the powder by baking at high temperature to increase the oxygen content in the powder and gave the calculation method of the oxygen content in the powder oxidation *** majority of oxygen element was found in the oxide particles in the powder and the oxide flm on the powder surface,which did affect the flowability of the *** is worth noting that the increase in the oxygen content does not change the phase of H13 steel,but it can promote the molten pool flow and obtain a smoother *** increase in the oxygen content in the powder is not the decisive factor for the formability and defects of the printed *** is the combined effect of the powder deformation,the increase in the oxygen content,and the impurity pollution after repeated use,which leads to the limitation of repeated utilization of the powder.
One-stage partial nitrification coupled with anammox(PN/A)technology effectively reduces the energy consumption of a biological nitrogen removal *** nitrite-oxidizing bacteria(NOB)is essential for this technology to m...
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One-stage partial nitrification coupled with anammox(PN/A)technology effectively reduces the energy consumption of a biological nitrogen removal *** nitrite-oxidizing bacteria(NOB)is essential for this technology to maintain efficient nitrogen removal *** ammonium concentration(IAC)affects the degree of inhibited *** this study,the effect of the IAC on a PN/A biofilm was investigated in a moving bed biofilm *** results showed that nitrogen removal efficiency decreased from 82.49%±1.90%to 64.57%±3.96%after the IAC was reduced from 60 to 20 mg N/L,while the nitrate production ratio increased from 13.87%±0.90%to 26.50%±3.76%.NOB activity increased to1,133.86 mg N/m^(2)/day after the IAC decreased,approximately 4-fold,indicating that the IAC plays an important inhibitory role in *** rate-limiting step in the mature biofilm of the PN/A system is the nitritation process and is not shifted by the *** analysis of the microbial community structure in the biofilm indicates that the IAC was the dominant factor in changes in community *** and *** were the main anammox bacteria,and Nitrosomonas and Nitrospira were the main AOB and NOB,*** did not affect the difference in growth between *** and ***,modulating the IAC promoted the PN/A process with efficient nitrogen removal performance at medium to low ammonium concentrations.
Thermo-mechanical experiments on martensitic heat-resistant 40Cr10Si2Mo steel were conducted using a Gleeble simulator in temperature and strain rate ranges of 1073–1373 K and 0.1–20 s^(-1),*** maps were developed a...
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Thermo-mechanical experiments on martensitic heat-resistant 40Cr10Si2Mo steel were conducted using a Gleeble simulator in temperature and strain rate ranges of 1073–1373 K and 0.1–20 s^(-1),*** maps were developed and correlated with deformed microstructures based on the dynamic material model *** analysis of the maps revealed that both applied temperature and strain rate had significant effects on the power dissipation efficiency and flow instability of the steel *** backscatter diffraction analysis was also implemented to study the effect of deformation conditions on martensitic *** results showed that higher temperatures and strain rates led to a fine martensitic packet,and the martensite lath increased in width at high *** deformation domains,which exhibit different recrystallization processes,were *** discontinuous dynamic recrystallization(DRX)mechanism in the low strain rate domain was characterized by the migration and growth of high-angle grains during *** contrast,in the high strain rate domain,the development of new grain boundaries is primarily associated with the deformation microbands in the low-temperature deformation *** the temperature increased,the high dislocation density accelerated the migration of the grain ***,the DRX mechanism changed from continuous DRX to *** change in the DRX mechanism type was attributed to the time during which the sample remained high temperature after deformation.
Central crack is a common quality defect in continuous casting strand,which is difficult to fully weld in the rolling and forging processes,and has become a key technical problem that restricts the stable production o...
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Central crack is a common quality defect in continuous casting strand,which is difficult to fully weld in the rolling and forging processes,and has become a key technical problem that restricts the stable production of high-end alloy rod/forging/*** recent years,the central crack control has been one of the main focuses in high quality steel *** order to fully understand the central crack,the research status of central crack characteristics,formation mechanism,influencing factors,and control methods in the world was *** deficiencies in the research of the central crack and the key research directions in the future were pointed out,which will provide references for other scholars in this field of *** is found that alloying elements segregation during solidification and inclusions precipitated at grain boundaries are the main reasons for the central crack formation,while the unreasonable application of production processes can also induce the initiation of central *** optimization of alloying element composition and production process is helpful to reduce the initiation of central *** addition,the quantitative characterization mechanism based on steel grades,temperature,stress,and other factors induced central crack should be established in the further study,forming a systematic quantitative determination criterion and control strategy for coupling the composition,process and thermal/mechanical characteristic.
Assessing the potential damage caused by earthquakes is crucial for a community’s emergency *** this study,four machine learning(ML)methods—random forest,extremely randomized trees,AdaBoost(AB),and gradient boosting...
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Assessing the potential damage caused by earthquakes is crucial for a community’s emergency *** this study,four machine learning(ML)methods—random forest,extremely randomized trees,AdaBoost(AB),and gradient boosting(GB)—were employed to develop prediction models for the damage potential of the mainshock(DIMS)and mainshock–aftershock sequences(DIMA).Building structures were modeled using eight single-degree-of-freedom(SDOF)systems with different hysteretic rules.A set of 662 recorded mainshock–aftershock(MS-AS)ground motions was selected from the PEER *** intensity measures(IMs)were chosen to represent the characteristics of the mainshock and *** results revealed that the selected ML methods can well predict the structural damage potential of the SDOF systems,except for the AB *** GB model exhibited the best performance,making it the recommended choice for predicting DIMS and DIMA among the four ML ***,the impact of input variables in the prediction was investigated using the shapley additive explanations(SHAP)*** high-correlation variables were sensitive to the structural period(T).At T=1.0 s,the mainshock peak ground velocity(PGVM)and aftershock peak ground displacement(PGDA)significantly influenced the prediction of *** T increased to 5.0 s,the primary high-correlation factor of the mainshock IMs changed from PGVM to the mainshock peak ground displacement(PGDM);however,the highcorrelation variable of the aftershock IMs remained *** high-correlation factors for DIMS showed trends similar to those of ***,a table summarizing the first and second high-correlation variables for predicting DIMS and DIMA were provided,offering a valuable reference for parameter selection in seismic damage prediction for mainshock–aftershock sequences.
The series of communal work to replace thatched roofs using community resources is called "fushin", and has been carried out by "yui", a community of 25 to 30 households, with one house per year, t...
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Indoor volatile organic compound(VOC)concentrations are often dynamic because the ventilation and emission rates of VOC usually *** filters used for air purification may operate with a capacity that fluctuates with un...
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Indoor volatile organic compound(VOC)concentrations are often dynamic because the ventilation and emission rates of VOC usually *** filters used for air purification may operate with a capacity that fluctuates with unsteady VOC concentrations in *** the dynamic interactions between adsorption filters and indoor air is crucial for predicting their performance under real-world *** study presents a numerical model of partially reversible adsorption equilibrium coupled with a mass transfer model to create a predictive model for adsorption efficiency in environments with dynamic VOC concentrations.A honeycomb adsorption filter for benzene adsorption was simulated and tested,including the breakthrough and purging curve and the long-term efficiency in an experimental chamber with dynamic *** results reveal that the curve generated with the partially reversible adsorption equilibrium model closely aligns with the measured ***,the model was coupled with a chamber model and the simulation results were compared with those calculated using the filter model with a single adsorption *** VOCs were emitted intermittently in the chamber and there was sufficient ventilation,the concentration peaks in the chamber derived from the models with different assumptions on adsorption reversibility were significantly different from each ***,it was observed that the reversible adsorption capacity of the filter was crucial for long-term operation in rooms with dynamic *** the reversible adsorption capacity constituting only 6.7%of the total adsorption capacity of the tested filter,it contributes to a significant“peak shaving and valley filling”effect,even when the irreversible adsorption capacity is *** adsorption reversibility should be taken as an important parameter for selecting adsorbents for dynamic concentration conditions.
The purpose of this study is to clarify the progress in recycling of finishing material waste after the enforcement of construction recycling law in 2002, and to further consider the future direction of recycling. The...
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