DYNAMIC CHARACTERISTICS OF A CANTILEVER BEAM WITH PARTIAL SELF-SENSING ACTIVE CONSTRAINED LAYER DAMPING TREATMENT

The equations of motion governing the vibration of a cantilever beam with partially treated self-sensing active constrained layer damping treatment(SACLD) are derived by application of the extended Hamilton principle. The assumed-modes method and closed loop velocity feedback control law are used to analyze and control the flexural vibration of the beam nle influences of the bonding layer and piezoelectric layer thickness, material properties, placements of the Diezoelectric patch and feedback control parameters on the actuation ability of the vibration suppression are investigated. Some design considerations for pure passive, pure active control, and self-sensing active constrained layer damping are discussed.

Design of a modern automatic control system for the activated sludge process in wastewater treatment

The Activated Sludge Process(ASP) exhibits highly nonlinear properties. The design of an automatic control system that is robust against disturbance of inlet wastewater flow rate and has short process settling times is a challenging matter. The proposed control method is an I-P modi fied controller automatic control system with state variable feedback and control canonical form simulation diagram for the process. A more stable response is achieved with this type of modern control. Settling times of 0.48 days are achieved for the concentration of microorganisms,(reference value step increase of 50 mg·L-1) and 0.01 days for the concentration of oxygen(reference value step increase of 0.1 mg·L-1). Fluctuations of concentrations of oxygen and microorganisms after an inlet disturbance of5 × 103m3·d-1are small. Changes in the reference values of oxygen and microorganisms(increases by 10%, 20% and 30%) show satisfactory response of the system in all cases. Changes in the value of inlet wastewater flow rate disturbance(increases by 10%, 25%, 50% and 100%) are stabilized by the control system in short time. Maximum percent overshoot is also taken in consideration in all cases and the largest value is 25% which is acceptable. The proposed method with I-P controller is better for disturbance rejection and process settling times compared to the same method using PI controller. This method can substitute optimal control systems in ASP.

Treatment of Hypertensive Cerebral Hemorrhage by Activating Blood Circulation to Remove Stasis

The treatment of hy-pertensive cerebral hemorrhage(HCH)by activatingblood circulation to removestasis(ABCRS)is a newtherapeutic approach,which is initiated by clinical specialists of TCM andintegrative Chinese andwestern medicine.Al-though it is not a flawless

Key factors governing alkaline pretreatment of waste activated sludge

Alkaline pretreatment is an effective technology to disintegrate sewage sludge, where alkali dosage and sludge concentration are two important factors. p H value or alkali concentration is usually adjusted in order to determine a proper dosage of alkali. Our work has found that this is not a good strategy. A new parameter, the ratio of alkali to sludge(Ra/s), is more sensitive in controlling the alkali dosage. The sludge concentration Csand retention time t are two other important factors to consider. The validity of these arguments is confirmed with modeling and experiments. The individual effect of Ra/s, Csand t was studied separately. Then the combined effect of these three factors was evaluated. The sludge disintegration degree of 44.7% was achieved with the optimized factors. Furthermore, an alkaline-microwave combined pretreatment process was carried out under these optimized conditions. A high disintegration degree of 62.3% was achieved while the energy consumption of microwave was much lower than previously reported.

A Survey of Experience Gained from the Treatment of Coal Mine Wastewater

During coal mining, water resources may be polluted by acid mine drainage (AMD) if appropriate measures are not taken. AMD releases metals to the environment, which can be harmful to aquatic species and reduce biodiversity. There is a great deal of information available in the literature on the generation and treatment of AMD and this paper tries to summarize some of them in order to facilitate the choice of the most appropriate method for AMD treatment at a specific mining site. The objective of this study was to identify and describe different methods of treating polluted water from coal mining, and to discuss the choice of suitable methods at specific mining sites. Both active and passive methods of AMD treatment are discussed in order to provide a general picture of the measures that have been taken around the world by coal mining companies. From this study, we were able to conclude that in order to choose the appropriate method for a specific mining site it is necessary to analyze the chemistry of the acid water and the flow rate from that site. The cost, implementability and effectiveness of the method should also be considered. Minimizing the amount of drainage water generated is naturally the first choice of management strategy and the containment of the AMD is the second choice. The third alternative is the treatment of the wastewater.

Effect of porosity on active damping of geometrically nonlinear vibrations of a functionally graded magneto-electro-elastic plate

This paper investigates the effect of porosity on active damping of geometrically nonlinear vibrations(GNLV)of the magneto-electro-elastic(MEE)functionally graded(FG)plates incorporated with active treatment constricted layer damping(ATCLD)patches.The perpendicularly/slanted reinforced 1-3 piezoelectric composite(1-3 PZC)constricting layer.The constricted viscoelastic layer of the ATCLD is modeled in the time-domain using Golla-Hughes-Mc Tavish(GHM)technique.Different types of porosity distribution in the porous magneto-electro-elastic functionally graded PMEE-FG plate graded in the thickness direction.Considering the coupling effects among elasticity,electrical,and magnetic fields,a three-dimensional finite element(FE)model for the smart PMEE-FG plate is obtained by incorporating the theory of layer-wise shear deformation.The geometric nonlinearity adopts the von K arm an principle.The study presents the effects of a variant of a power-law index,porosity index,the material gradation,three types of porosity distribution,boundary conditions,and the piezoelectric fiber’s orientation angle on the control of GNLV of the PMEE-FG plates.The results reveal that the FG substrate layers’porosity significantly impacts the nonlinear behavior and damping performance of the PMEE-FG plates.

PLATELET ACTIVATION IN PATIENTS WITH CHRONIC PULMONARY HEART DISEASE EFFECT OF DIPYRIDAMOLE TREATMENT

Plasma levels of /f-thromboglobulin (/?-TG), platelet fac-tor 4(P and platelet aggregation rate (PAR) were measured in remission phase of 15 patients affected with chronic pulmonary heart disease (CPHD). 0-TG, /?-TG / PF4, PF4 and PAR were significantly higher in the patients than in controls (/3<0.01 and 0.05, respectively). After 10 days of treatment with Dipyridamole lOOtng tid, fi-TG, /?-TG / PF4 and PF4 decreased significantly compared with pretreatment values (/><0.01 and 0.05, respectively). The results suggest that in vivo platelet activation is indeed present in patients with CPHD and that dipyridamole can antagonize platelet activation in vivo.

Experimental Design Technique on Removal of Hydrogen Sulfide using CaO-eggshells Dispersed onto Palm Kernel Shell Activated Carbon：Experiment,Optimization,Equilibrium and Kinetic Studies

This study presents the use of chicken eggshells waste utilizing palm kernel shell based activated carbon（PKSAC） through the modification of their surface to enhance the adsorption capacity of H2S. Response surface methodology technique was used to optimize the process conditions and they were found to be： 500 mg/L for H2S initial concentration, 540 min for contact time and 1 g for adsorbent mass. The impacts of three arrangement factors（calcination temperature of impregnated activated carbon（IAC）, the calcium solution concentration and contact time of calcination） on the H2S removal efficiency and impregnated AC yield were investigated. Both responses IAC yield（IACY, %） and removal efficiency（RE, %） were maximized to optimize the IAC preparation conditions. The optimum preparation conditions for IACY and RE were found as follows： calcination temperature of IAC of 880 ℃, calcium solution concentration of 49.3% and calcination contact time of 57.6 min, which resulted in 35.8% of IACY and 98.2% RE. In addition, the equilibrium and kinetics of the process were investigated. The adsorbent was characterized using TGA, XRD, FTIR, SEM/EDX, and BET. The maximum monolayer adsorption capacity was found to be 543.47 mg/g. The results recommended that the composite of PKSAC and Ca O could be a useful material for H2S containing wastewater treatment.

Treatment status of extremely premature infants with gestational age<28 weeks in a Chinese perinatal center from 2010 to 2019

Background There is a paucity of studies conducted in China on the outcomes of all live-birth extremely premature infants(EPIs)and there is no unifed recommendation on the active treatment of the minimum gestational age in the feld of perinatal medicine in China.We aimed to investigate the current treatment situation of EPIs and to provide evidence for formulating reasonable treatment recommendations.Methods We established a real-world ambispective cohort study of all live births in delivery rooms with gestational age(GA)between 24+0 and 27+6 weeks from 2010 to 2019.Results Of the 1163 EPIs included in our study,241(20.7%)survived,while 849(73.0%)died in the delivery room and 73(6.3%)died in the neonatal intensive care unit.Among all included EPIs,862(74.1%)died from withholding or withdrawal of care.Regardless of stratifcation according to GA or birth weight,the proportion of total mortality attributable to withdrawal of care is high.For infants with the GA of 24 weeks,active treatment did not extend their survival time(P=0.224).The survival time without severe morbidity of the active treatment was signifcantly longer than that of withdrawing care for infants older than 25 weeks(P<0.001).Over time,the survival rate improved,and the withdrawal of care caused by socioeconomic factors and primary nonintervention were reduced signifcantly(P<0.001).Conclusions The mortality rate of EPIs is still high.Withdrawal of care is common for EPIs with smaller GA,especially in the delivery room.It is necessary to use a multi-center,large sample of real-world data to fnd the survival limit of active treatment based on our treatment capabilities.

Disinfection byproduct formation from algal organic matters after ozonation or ozone combined with activated carbon treatment with subsequent chlorination

Algal organic matter(AOM),including extracellular organic matter(EOM)and intracellular organic matter(IOM)from algal blooms,is widely accepted as essential precursors of disinfection byproducts(DBPs).This study evaluated the effect of ozonation or ozone combined with activated carbon(O_(3)-AC)treatment on characteristic alternation and DBP formation with subsequent chlorination of Chlorella sp..The effects of p H and bromide concentration on DBP formation by ozonation or O_(3)-AC treatment were also investigated.Results showed that the potential formation of DBPs might be attributed to ozonation,but these DBP precursors could be further removed by activated carbon(AC)treatment.Moreover,the formation of target DBPs was controlled at acidic pH by alleviating the reactions between chlorine and AOM.Besides,the bromide substitution factor(BSF)value of trihalomethanes(THMs)from EOM and IOM remained constant after AC treatment.However,THM precursors could be significantly decreased by AC treatment.The above results indicated that O_(3)-AC was a feasible treatment method for algal-impacted water.

Occurrence,distribution,and potential influencing factors of sewage sludge components derived from nine full-scale wastewater treatment plants of Beijing,China

Millions of tons of waste activated sludge（WAS） produced from biological wastewater treatment processes cause severe adverse environmental consequences. A better understanding of WAS composition is thus very critical for sustainable sludge management. In this work, the occurrence and distribution of several fundamental sludge constituents were explored in WAS samples from nine full-scale wastewater treatment plants（WWTPs） of Beijing, China. Among all the components investigated, active heterotrophic biomass was dominant in the samples（up to 9478 mg/L）, followed by endogenous residues（6736 mg/L）,extracellular polymeric substances（2088 mg/L）, and intracellular storage products（464 mg/L）among others. Moreover, significant differences（p 〈 0.05） were observed in composition profiles of sludge samples among the studied WWTPs. To identify the potential parameters affecting the variable fractions of sludge components, wastewater source as well as design and operational parameters of WWTPs were studied using statistical methods. The findings indicated that the component fraction of sewage sludge depends more on wastewater treatment alternatives than on wastewater characteristics among other parameters. A principal component analysis was conducted, which further indicated that there was a greater proportion of residual inert biomass in the sludge produced by the combined system of the conventional anaerobic/anoxic/oxic process and a membrane bioreactor. Additionally, a much longer solids retention time was also found to influence the sludge composition and induce an increase in both endogenous inert residues and extracellular polymeric substances in the sludge.

Competitive effects of humic acid and wastewater on adsorption of Methylene Blue dye by activated carbon and non-imprinted polymers

Natural organic matter（NOM）, present in natural waters and wastewater, decreases adsorption of micropollutants, increasing treatment costs. This research investigated mechanisms of competition for non-imprinted polymers（NIPs） and activated carbon with humic acid and wastewater. Three different types of activated carbons（Norit PAC 200,Darco KB-M, and Darco S-51） were used for comparison with the NIP. The lower surface area and micropore to mesopore ratio of the NIP led to decreased adsorption capacity in comparison to the activated carbons. In addition, experiments were conducted for single-solute adsorption of Methylene Blue（MB） dye, simultaneous adsorption with humic acid and wastewater, and pre-loading with humic acid and wastewater followed by adsorption of MB dye using NIP and Norit PAC 200. Both the NIP and PAC 200 showed significant decreases of 27% for NIP（p = 0.087） and 29% for PAC 200（p = 0.096） during simultaneous exposure to humic acid and MB dye. There was no corresponding decrease for NIP or PAC 200 pre-loaded with humic acid and then exposed to MB. In fact, for PAC 200, the adsorption capacity of the activated carbon increased when it was pre-loaded with humic acid by 39%（p = 0.0005）. For wastewater, the NIP showed no significant increase or decrease in adsorption capacity during either simultaneous exposure or pre-loading. The adsorption capacity of PAC 200 increased by 40%（p = 0.001） for simultaneous exposure to wastewater and MB. Pre-loading with wastewater had no effect on MB adsorption by PAC 200.