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Enhancement of sludge gravitational thickening with weak ultrasound

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Frontiers of Environmental Science & Engineering 2012年第5期6卷 753-760页

作者： Panyue zhang Tian WAN guangming zhang School of Environment Science and Engineering Hunan UniversityChangsha 410082China State Key Laboratory of Urban Water Resource and Environment Harbin Institute of TechnologyHarbin 150090China

Gravitational thickening is the prevailing method to reduce sludge volume but the process is slow and usually requires addition of polyelectrolyte（s）. This paper investigated the potential benefits of sonication on enhancing the sludge gravitational thickening with very low energy dose, so called ＂weak ultrasound＂. Results showed that weak sonication significantly changed the sludge settlability and the main mechanism was release of the loosely bounded extracellular polymeric substances. The changes in sludge behaviors by sonication were strongly influenced by power density and sonication duration. Lower sound frequency was slightly better than higher frequency. Weak sonication （〈 680 ***1 DS） improved the sludge gravitational thickening while high ultrasonic energy deteriorated the process. Considering both the sludge thickening efficiency and energy con- sumption the optimum conditions were 0.15 W. mL-l, 7 s, and 25 kHz. Under such conditions, the energy dose was only 155 ***-1 DS, much lower than literature reports, and the sludge settling time was shortened from 24 h to 12 h. Weak sonication could substitute expensive poly- electrolyte coagulant for sludge thickening. Combination of weak sonication and polyelectrolyte could further reduce the settling time to 6 h. The final water content of the thickened sludge was not changed after sonication or polyelectrolyte addition.

关键词： activated sludge sonication settlability dryweight extracellular polymeric substances polyelectrolyte

Mg^(2+) improves biomass production from soybean wastewater using purple non-sulfur bacteria

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Journal of Environmental Sciences 2015年第2期27卷 43-46页

作者： Pan Wu guangming zhang Jianzheng Li State Key Laboratory of Urban Water Resource and Environment Harbin Institute of Technology School of Environment & Resource Renmin University of China

Soybean wastewater was used to generate biomass resource by use of purple non-sulfur bacteria（PNSB）. This study investigated the enhancement of PNSB cell accumulation in wastewater by Mg2＋under the light-anaerobic condition. Results showed that with the optimal Mg2＋dosage of 10 mg/L, biomass production was improved by 70% to 3630 mg/L,and biomass yield also was improved by 60%. Chemical Oxygen Demand（COD） removal reached above 86% and hydraulic retention time was shortened from 96 to 72 hr. The mechanism analysis indicated that Mg2＋could promote the content of bacteriochlorophyll in photosynthesis because Mg2＋is the bacteriochlorophyll active center, and thus improved adenosine triphosphate（ATP） production. An increase of ATP production enhanced the conversion of organic matter in wastewater into PNSB cell materials（biomass yield） and COD removal, leading to more biomass production. With 10 mg/L Mg2＋, bacteriochlorophyll content and ATP production were improved by 60% and 33% respectively.

关键词： Purple non-sulfur bacteria Mg2+ Biomass resource Soybean wastewater Photosynthesis

Research on FMC analytic algorithm of PBN track transition coding

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Journal of Systems Engineering and Electronics 2023年第4期34卷 1042-1052页

作者： zhang guangming REN Siqian ZHAO Weiwei LI Xiuyi School of Flight Technology Civil Aviation Flight University of ChinaGuanghan 618307China

Airborne navigation database(NavDB)coding directly affects the result of analysis on the instrument flight procedure by the modern aircraft flight management computer(FMC).A reasonable flight track transition mode can improve the track tracking accuracy and flight quality of the *** to the path terminator(PT)and track transition characteristics of the performance based navigation(PBN)instrument flight procedure and by use of the world geodetic system(WGS)-84 ellipsoidal coordinate system,the algorithms for“fly by”and“fly over”track transition connections are developed,together with the algorithms for coordinates of fix-to-altitude(FA)altitude termination point and heading-to-an-intercept(VI)track entry point and for track transition display of the navigation display(ND).According to the simulation carried out based on the PBN instrument approach procedure coding of a certain airport and the PBN route data at a high altitude,the algorithm results are consistent with the FMC-calculated results and the actual ND results.

关键词： flight management computer(FMC) performance based navigation(PBN) path terminator(PT) navigation database(NavDB)coding track transition

N:P stoichiometry in Ficus racemosa and its mutualistic pollinator

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Journal of Plant Ecology 2010年第2期3卷 123-130页

作者： guangming zhang Xingguo Han State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China Graduate University of Chinese Academy of Sciences Beijing 100049China

Aims Nitrogen(N)and phosphorus(P)are limiting nutrients to life across a variety of ecosystems.N:P stoichiometry,concerning the balance of these two elements,has recently received great ***,little is known about the nature of N:P stoichiometry in obligate *** N:P stoichiometry of Ficus racemosa and its pollinating wasp Ceratosolen fusciceps,an example of coevolving obligate mutualism,was investigated,and the N:P stoichiometric traits of male versus female wasps were *** Findings Nutrient concentrations in *** were much higher than in its host.N enrichment in fig wasp was evidently stronger than phosphorus.N concentrations of male fig wasps were significantly higher than those of females,while P concentrations of female fig wasps were remarkably higher than those ofmale ***,N:P ratios inmale fig wasps were significantly greater than in female fig wasps.N:P ratio in fig-pollinating wasp displayed linear functions to fig N contents,suggesting that N limitation in fig wasps may dominate the nutritional relationship between fig pollinator and its *** wasp population size had significant influences on N concentrations in host fig and female wasp per *** by the nutritional stress of pollinating and parasite insects,fig fruit preferred increasing its diameter first but not nutrient *** forNand P contents of fig pollinators showed seasonal differenceswith greater N:P ratios in dry season than in rainy *** observations suggest that tropical climate change would result in more severe N limitation to fig-pollinating wasp and may further influence the stability of fig–fig wasp mutualism.

关键词： N:P stoichiometry ficus racemosa fig wasp sex divergence mutualism coevolution tropical rainforest human disturbance Xishuangbanna

Enhancement of ultrasonic disintegration of sewage sludge by aeration

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Journal of Environmental Sciences 2016年第4期28卷 163-167页

作者： He Zhao Panyue zhang guangming zhang Rong Cheng School of Environment and Natural Resource Renmin University of China College of Environmental Science and Engineering Beijing Forestry University

Sonication is an effective way for sludge disintegration,which can significantly improve the efficiency of anaerobic digestion to reduce and recycle use of *** high energy consumption limits the wide application of *** order to improve ultrasonic sludge disintegration efficiency and reduce energy consumption,aeration was *** showed that sludge disintegration efficiency was improved significantly by combining aeration with *** aeration flow rate,gas bubble size,ultrasonic density and aeration timing had impacts on sludge disintegration *** that used in later stage of ultrasonic irradiation with low aeration flow rate,small gas bubbles significantly improved ultrasonic disintegration sludge *** the optimal conditions of 0.4 W/m L ultrasonic irradiation density,30 m L/min of aeration flow rate,5 min of aeration in later stage and small gas bubbles,ultrasonic sludge disintegration efficiency was increased by 45% and one third of ultrasonic energy was *** approach will greatly benefit the application of ultrasonic sludge disintegration and strongly promote the treatment and recycle of wastewater sludge.

关键词： Aeration Ultrasonic sludge disintegration Gas bubble size Ultrasonic irradiation density Ultrasonic irradiation stages

Treatment of soybean wastewater by a wild strain Rhodobacter sphaeroides and to produce protein under natural conditions

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Frontiers of Environmental Science & Engineering 2010年第3期4卷 334-339页

作者： Junguo HE guangming zhang Haifeng LU State Key Lab of Urban Water Resource and Environment Harbin Institute of TechnologyHarbin 150090China

The conventional treatment method of soybean wastewater is expensive and generates waste sludge that requires further *** nonsulfur bacteria(PNSB)wastewater treatment is a clean technology and can generate single cell protein while degrading pollutants.A wild strain of PNSB,Rhodobacter sphaeroides Z08,was isolated from local soil and was used to treat soybean *** develop a cost-effective process,the work was performed under natural conditions without artificial light,aeration,nutrients addition,or pH and temperature *** results showed that the wild strain Rhodobacter sphaeroides Z08 could grow well under natural *** growth curve showed two quickgrowth periods and a turning *** Z08 treatment of soybean wastewater was zero order reaction and COD reduction was 96%after 10 *** major byproducts of the process were C2-C5 organic acids,predominantly butyric *** alcohol was found in the *** initial COD/bacterial-mass ratio(F/M)had a significant effect on soybean wastewater treatment *** the initial F/M was lower than 10 mg-COD/mg-bacteria,a sufficient amount of time to achieve 90%of COD reduction was only three *** Z08 biomass yield was 0.28 g·g^(–1),and the bacterial protein content was 52%.

关键词： purple nonsulfur bacteria(PNSB) Rhodobacter sphaeroides Z08 soybean wastewater cost effective

Optimization-based particle filter for state and parameter estimation

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Journal of Systems Engineering and Electronics 2009年第3期20卷 479-484页

作者： Li Fu Qi Fei Shi guangming zhang Li School of Electronic Engineering Xidian Univ. Xi'an 710071 P. R. China

In recent years, the theory of particle filter has been developed and widely used for state and parameter estimation in nonlinear/non-Gaussian systems. Choosing good importance density is a critical issue in particle filter design. In order to improve the approximation of posterior distribution, this paper provides an optimization-based algorithm （the steepest descent method） to generate the proposal distribution and then sample particles from the distribution. This algorithm is applied in 1-D case, and the simulation results show that the proposed particle filter performs better than the extended Kalman filter （EKF）, the standard particle filter （PF）, the extended Kalman particle filter （PF-EKF） and the unscented particle filter （UPF） both in efficiency and in estimation precision.

关键词： importance density particle filter extend Kalman filter

Enhancement of Rhodobacter sphaeroides growth and carotenoid production through biostimulation

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Journal of Environmental Sciences 2015年第7期27卷 21-28页

作者： Shuli Liu guangming zhang Xiangkun Li Pan Wu Jie zhang School of Municipal and Environmental Engineering Harbin Institute of Technology School of Environment and Resource Renmin University of China

Bacillus thuringiensis/cereus L2 was added as a biostimulant to enhance the biomass accumulation and carotenoid yield of Rhodobacter sphaeroides using wastewater as the culturing medium. Results showed that biostimulation could significantly enhance the R. sphaeroides biomass production and carotenoid yield. The optimal biostimulant proportion was 40 μL（about 6.4 × 10^5CFU）. Through the use of biostimulation, chemical oxygen demand removal, R. sphaeroides biomass production, carotenoid concentration, and carotenoid yield were improved by 178%, 67%, 214%, and 70%, respectively. Theoretical analysis revealed that there were two possible reasons for such increases. One was that biostimulation enhanced the R. sphaeroides wastewater treatment efficiency. The other was that biostimulation significantly decreased the peroxidase activity in R. sphaeroides. The results showed that the highest peroxidase activity dropped by 87% and the induction ratio of the RSP_3419 gene was 3.1 with the addition of biostimulant. The enhanced carotenoid yield in R. sphaeroides could thus be explained by a decrease in peroxidase activity.

关键词： Biostimulant Rhodobaeter sphaeroides Biomass Carotenoid yield

Rapid degradation of dyes in water by magnetic Fe^0/Fe_3O_4/graphene composites

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Journal of Environmental Sciences 2016年第6期28卷 148-157页

作者： Shan Chong guangming zhang Huifang Tian He Zhao School of Environment & Natural Resource Renmin University of China

Magnetic Fe^0/Fe3O4/graphene has been successfully synthesized by a one-step reduction method and investigated in rapid degradation of dyes in this work. The material was characterized by N2 sorption–desorption, scanning electron microscopy（SEM）, Fourier transform infrared spectroscopy（FT-IR）, vibrating-sample magnetometer（VSM） measurements and X-ray photoelectron spectroscopy（XPS）. The results indicated that Fe^0/Fe3O4/graphene had a layered structure with Fe crystals highly dispersed in the interlayers of graphene, which could enhance the mass transfer process between Fe^0/Fe3O4/graphene and pollutants. Fe^0/Fe3O4/graphene exhibited ferromagnetism and could be easily separated and re-dispersed for reuse in water. Typical dyes, such as Methyl Orange, Methylene Blue and Crystal Violet, could be decolorized by Fe^0/Fe3O4/graphene rapidly. After 20 min, the decolorization efficiencies of methyl orange, methylene blue and crystal violet were 94.78%, 91.60% and 89.07%, respectively. The reaction mechanism of Fe^0/Fe3O4/graphene with dyes mainly included adsorption and enhanced reduction by the composite. Thus, Fe^0/Fe3O4/graphene prepared by the one-step reduction method has excellent performance in removal of dyes in water.

关键词： Fe^0/Fe3O4/graphene Magnetic Dyes Removal Reduction