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Effects of operating conditions on membrane charge property and nanofiltration

Li XU, Li-Shun DU, Jing HE

《化学科学与工程前沿（英文）》 2011年 第5卷 第4期   页码 492-499 doi: 10.1007/s11705-011-1143-7

摘要： The effects of the operating pressure, cross flow velocity, feed concentration, and temperature on the streaming and Zeta potential of the membranes were studied. The permeate flux and the retention rate under different nanofiltration operating conditions were also investigated. The results show that the higher pressure, feed concentration, temperature, and lower cross flow velocity lead to the higher absolute value of streaming and Zeta potential. The permeate flux of the nanofiltration decreases with the feed concentration and increases with not only the pressure but also the cross flow velocity and temperature. The higher the pressure and the cross flow velocity, the higher the retention rate. The lower feed concentration and higher temperature leads to lower retention rate. The effects of the operating conditions on the permeate flux and the retention rate were explained by the variation of the membrane charge property.

关键词： nanofiltration membrane     streaming potential     Zeta potential     permeate flux     retention rate    

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Modelling the thresholds of nitrogen/phosphorus concentration and hydraulic retention time for bloom

《环境科学与工程前沿（英文）》 2022年 第16卷 第10期 doi: 10.1007/s11783-022-1564-1

摘要：

● A new model for bloom control in open land scape water was constructed.

关键词： Reclaimed water landscape     Algal bloom     Nitrogen and phosphorus     Hydraulic retention time     Threshold     Control model    

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Effects of hydraulic retention time on nitrification activities and population dynamics of a conventional

Hongyan LI, Yu ZHANG, Min YANG, Yoichi KAMAGATA

《环境科学与工程前沿（英文）》 2013年 第7卷 第1期   页码 43-48 doi: 10.1007/s11783-012-0397-8

摘要： The effects of hydraulic retention time (HRT) on the nitrification activities and population dynamics of a conventional activated sludge system fed with synthetic inorganic wastewater were investigated over a period of 260 days. When the HRT was gradually decreased from 30 to 5 h, the specific ammonium-oxidizing rates (SAOR) varied between 0.32 and 0.45 kg (kg mixed liquor suspended solids (MLSS)·d) , and the specific nitrate-forming rates (SNFR) increased from 0.11 to 0.50 kg (kg MLSS·d) , showing that the decrease in HRT led to a significant increase in the nitrite oxidation activity. According to fluorescence in situ hybridization (FISH) analysis results, the proportion of ammonia-oxidizing bacteria (AOBs) among the total bacteria decreased from 33% to 15% with the decrease in HRT, whereas the fraction of nitrite-oxidizing bacteria (NOBs), particularly the fast-growing sp., increased significantly (from 4% to 15% for NOBs and from 1.5% to 10.6% for sp.) with the decrease in HRT, which was in accordance with the changes in SNFR. A short HRT favored the relative growth of NOBs, particularly the fast-growing sp., in the conventional activated sludge system.

关键词： ammonia-oxidizing bacteria     hydraulic retention time     nitrification activity     nitrite-oxidizing bacteria     population dynamics    

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Sustaining health workforce recruitment and retention in township hospitals: a survey on 110 directors

null

《医学前沿（英文）》 2015年 第9卷 第2期   页码 239-250 doi: 10.1007/s11684-015-0392-0

摘要：

Township hospitals, the main provider of rural primary healthcare in China, are severely understaffed. International studies on factors influencing rural working are increasing; however, studies on factors affecting the recruitment and retention of health workers in Chinese township hospitals are limited. The current study aims to understand the motivation of health workers and arrive at a systematic framework of pluralistic factors that would help support health workers in terms of receiving posts and remaining in posts in township hospitals. A three-stage integrated quantitative and qualitative methodology was employed. First, a survey on 120 directors of township hospitals was conducted to learn the latest status of health workers in township hospitals and distinguish existing problems. Second, after sending these problems back to the directors, an open-ended pen-and-paper survey was conducted to ask the directors to identify the factors influencing the attraction and retention of health workers in township hospitals. Third, four focus groups were conducted to gauge the underlying reasons. Five problems from the questionnaire survey were recognized, and numbers of thematic factors were identified at the individual, professional, and treatment environment from the pen-and-paper survey and focus group. Similar to other studies, this framing of both non-financial and financial elements affected the attraction and retention of health workers in township hospitals, thereby filling the gap in a Chinese context. Although several factors had been recognized earlier, our findings further highlighted the importance of these factors. Meanwhile, the factors identified in this study were barely explored in literature. This paper identifies and develops multi-faceted factors to call for a bundled package of multidimensional incentives if decision-makers get interested. The evidence-based findings in our study can be used to provide China-specific policy recommendations on how to recruit and retain health workers in rural areas of China.

关键词： recruitment     retention     health workers     township hospitals     rural regions    

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EFFECT OF EXOGENOUS ADDITIVES ON HEAVY METAL PASSIVATION AND NITROGEN RETENTION IN PIG MANURE COMPOSTING

《农业科学与工程前沿（英文）》 doi: 10.15302/J-FASE-2023487

摘要：

● Research on heavy metal passivation and nitrogen emissions is necessary for the pig industry.

关键词： additives     composting     heavy metals passivation     nitrogen retention     pig manure    

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Bio-based Waterborne Poly(Vanillin-Butyl Acrylate)/MXene Coatings for Leather with Desired Warmth Retention

Jianzhong Ma,Li Ma,Lei Zhang,Wenbo Zhang,Qianqian Fan,Buxing Han,

《工程（英文）》 doi: 10.1016/j.eng.2023.06.005

摘要： This study presents a solvent-free, facile synthesis of a bio-based green antibacterial agent and aromatic monomer methacrylated vanillin (MV) using vanillin. The resulting MV not only imparted antibacterial properties to coatings layered on leather, but could also be employed as a green alternative to petroleum-based carcinogen styrene (St). Herein, MV was copolymerized with butyl acrylate (BA) to obtain waterborne bio-based P(MV–BA) miniemulsion via miniemulsion polymerization. Subsequently, MXene nanosheets with excellent photothermal conversion performance and antibacterial properties, were introduced into the P(MV–BA) miniemulsion by ultrasonic dispersion. During the gradual solidification of P(MV–BA)/MXene nanocomposite miniemulsion on the leather surface, MXene gradually migrated to the surface of leather coatings due to the cavitation effect of ultrasonication and amphiphilicity of MXene, which prompted its full exposure to light and bacteria, exerting the maximum photothermal conversion efficiency and significant antibacterial efficacy. In particular, when the dosage of MXene nanosheets was 1.4 wt%, the surface temperature of P(MV–BA)/MXene nanocomposite miniemulsion-coated leather (PML) increased by about 15 °C in an outdoor environment during winter, and the antibacterial rate against Escherichia coli and Staphylococcus aureus was nearly 100% under the simulated sunlight treatment for 30 min. Moreover, the introduction of MXene nanosheets increased the air permeability, water vapor permeability, and thermal stability of these coatings. This study provides a new insight into the preparation of novel, green, and waterborne bio-based nanocomposite coatings for leather, with desired warmth retention and antibacterial properties. It can not only realize zero-carbon heating based on sunlight in winter, reducing the use of fossil fuels and greenhouse gas emissions, but also improve ability to fight off invasion by harmful bacteria, viruses, and other microorganisms.

关键词： MXene nanosheets     Vanillin     Styrene substitute     Leather coating     Photothermal conversion     Warmth retention     Antibacterial properties    

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Influence of hydraulic retention time on behavior of antibiotics and antibiotic resistance genes in aerobic

Jie Liao, Chaoxiang Liu, Lin Liu, Jie Li, Hongyong Fan, Jiaqi Ye, Zhichao Zeng

《环境科学与工程前沿（英文）》 2019年 第13卷 第3期 doi: 10.1007/s11783-019-1115-6

摘要：

Longer HRT can enhance degradation rate of sulfamethoxazole in granular reactor.

Longer HRT can reduce accumulated concentrations of TCs and QNs in sludge.

Longer HRT may have increased relative abundances of ARGs in aerobic granules.

关键词： Aerobic granules     Swine wastewater     Tetracyclines     Fluoroquinolones     Sulfonamides    

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Effects of hydraulic retention time on net present value and performance in a membrane bioreactor treating

Dawei Yu, Jianxing Wang, Libin Zheng, Qianwen Sui, Hui Zhong, Meixue Cheng, Yuansong Wei

《环境科学与工程前沿（英文）》 2020年 第14卷 第6期 doi: 10.1007/s11783-020-1280-7

摘要： Abstract • The membrane bioreactor cost decreased by 38.2% by decreasing HRT from 72 h to 36 h. • Capital and operation costs contributed 62.1% and 37.9% to decreased costs. • The membrane bioreactor is 32.6% cheaper than the oxidation ditch for treatment. • The effluent COD also improved from 709.93±62.75 mg/L to 280±17.32 mg/L. • Further treatment also benefited from lower pretreatment investment. A cost sensitivity analysis was performed for an industrial membrane bioreactor to quantify the effects of hydraulic retention times and related operational parameters on cost. Different hydraulic retention times (72–24 h) were subjected to a flat-sheet membrane bioreactor updated from an existing 72 h oxidation ditch treating antibiotic production wastewater. Field experimental data from the membrane bioreactor, both full-scale (500 m3/d) and pilot (1.0 m3/d), were used to calculate the net present value (NPV), incorporating both capital expenditure (CAPEX) and operating expenditure. The results showed that the tank cost was estimated above membrane cost in the membrane bioreactor. The decreased hydraulic retention time from 72 to 36 h reduced the NPV by 38.2%, where capital expenditure contributed 24.2% more than operational expenditure. Tank construction cost was decisive in determining the net present value contributed 62.1% to the capital expenditure. The membrane bioreactor has the advantage of a longer lifespan flat-sheet membrane, while flux decline was tolerable. The antibiotics decreased to 1.87±0.33 mg/L in the MBR effluent. The upgrade to the membrane bioreactor also benefited further treatments by 10.1%–44.7% lower direct investment.

关键词： Antibiotic production wastewater     Net present value     Membrane bioreactor     Hydraulic retention time     Pollutant removal    

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Cotransfecting norepinephrine transporter and vesicular monoamine transporter 2 genes for increased retention

null

《医学前沿（英文）》 2017年 第11卷 第1期   页码 120-128 doi: 10.1007/s11684-017-0501-3

摘要：

Norepinephrine transporter (NET) transfection leads to significant uptake of iodine-131-labeled metaiodobenzylguanidine (131I-MIBG) in non-neuroendocrine tumors. However, the use of 131I-MIBG is limited by its short retention time in target cells. To prolong the retention of 131I-MIBG in target cells, we infected hepatocarcinoma (HepG2) cells with Lentivirus-encoding human NET and vesicular monoamine transporter 2 (VMAT2) genes to obtain NET-expressing, NET-VMAT2-coexpressing, and negative-control cell lines. We evaluated the uptake and efflux of 131I-MIBG both in vitro and in vivo in mice bearing transfected tumors. NET-expressing and NET-VMAT2-coexpressing cells respectively showed 2.24 and 2.22 times higher 131I-MIBG uptake than controls. Two hours after removal of 131I-MIBG-containing medium, 25.4% efflux was observed in NET-VMAT2-coexpressing cells and 38.6% in NET-expressing cells. In vivo experiments were performed in nude mice bearing transfected tumors; results revealed that NET-VMAT2-coexpressing tumors had longer 131I-MIBG retention time than NET-expressing tumors. Meanwhile, NET-VMAT2-coexpressing and NET-expressing tumors displayed 0.54% and 0.19%, respectively, of the injected dose per gram of tissue 24 h after 131I-MIBG administration. Cotransfection of HepG2 cells with NET and VMAT2resulted in increased 131I-MIBG uptake and retention. However, the degree of increase was insufficient to be therapeutically effective in target cells.

关键词： norepinephrine transporter     vesicular monoamine transporter 2     -MIBG     gene therapy     lentivirus vector    

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The combined effects of biomass and temperature on maximum specific ammonia oxidation rate in domestic

《环境科学与工程前沿（英文）》 2021年 第15卷 第6期 doi: 10.1007/s11783-021-1411-9

摘要：

• Actual SAORs was determined using MLVSS and temperature.

关键词： Specific ammonia oxidation rate     Sequencing batch reactor     Biomass     Temperature coefficient     Model simulation    

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Use of float consumption rate in resource leveling of construction projects

Atilla DAMCI, Gul POLAT, Firat Dogu AKIN, Harun TURKOGLU

《工程管理前沿（英文）》 2022年 第9卷 第1期   页码 135-147 doi: 10.1007/s42524-020-0118-0

摘要： The management of resources has been claimed to be as important as scheduling methods. Inefficiency in managing resources may bring about severe delays and cost overruns caused by resource shortages in some cases and/or idle resources in others. Therefore, resources should be utilized efficiently to prevent project failures. Resource leveling is one of the approaches that are used for the management of resources. It aims to minimize fluctuations, peaks, and valleys in resource utilization without changing the completion time of a project and the number of resources required. Although the main principle behind traditional resource leveling is achieving an even flow of resources while the original project duration remains unchanged, the literature supports the need to develop an efficient model that discriminates among the activities that are selected for participation in resource leveling. For this purpose, this study has developed a model that considers the float consumption rates of activities in resource leveling. The float consumption rate is the percentage that is set to determine the maximum amount of float which will be consumed to shift the start time of the activity. The proposed model allows a scheduler to assign float consumption rates to each activity that can be used during the resource leveling procedure. When the required information is inputted, the proposed model automatically changes the required daily resources as it shifts the noncritical activities along their available total float times. The proposed model is expected to minimize the likelihood of severe delays and cost overruns. The model is demonstrated by constructing a network and its resource utilization histograms.

关键词： resource management     resource leveling     float consumption rate     scheduling    

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Effect of biochar amendment on soil’s retention capacity for estrogenic hormones from poultry manure

Sukhjot MANN, Zhiming QI, Shiv O. PRASHER, Lanhai LI, Dongwei GUI, Qianjing JIANG

《农业科学与工程前沿（英文）》 2017年 第4卷 第2期   页码 208-219 doi: 10.15302/J-FASE-2017138

摘要： Most animals, including humans, produce natural sex hormones such as estrogens: 17β-estradiol (E2) and estrone (E1). These compounds are able to disrupt the reproductive systems of living organisms at trace concentrations (ng·L ). This experiment tests the hypothesis that 1% slow pyrolysis biochar-amended sandy soil could retain significant amount of estrogens (E1, E2) from poultry manure in its second year of application. The experiment was conducted over 46 days and consisted of a series of lysimeters containing sandy soil with biochar-amended topsoil. The application rate of poultry manure was kept at 2.47 kg·m . The biochar held a significant concentration of hormone during the first year of its application. However, in the following year (current study), there was no significant retention of hormones in the biochar-amended soil. During the first year after application, the biochar was fresh, so its pores were available for hydrophobic interactions and held significant concentration of hormones. As time passed there were several biotic and abiotic changes on the surface of the biochar so that after some physical fragmentation, pores on the surface were no longer available for hydrophobic interactions. The biochar started releasing dissolved organic carbon, which facilitated greater mobility of hormones from poultry manure down the soil profile.

关键词： adsorption     degradation     dissolved organic carbon     17β-estradiol (E2)     estrone (E1)    

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Effect of loading rate on shear strength parameters of mechanically and biologically treated waste

《环境科学与工程前沿（英文）》 2022年 第16卷 第12期 doi: 10.1007/s11783-022-1595-7

摘要：

● Mechanical behavior of MBT waste affected by loading rate was investigated.

关键词： Mechanically and biologically treated waste     Landfill     Triaxial test     Loading rate     Axial strain     Shear strength parameter    

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Nitrogen-retaining property of compost in an aerobic thermophilic composting reactor for the sanitary disposal of human feces

Fan BAI, Xiaochang WANG,

《环境科学与工程前沿（英文）》 2010年 第4卷 第2期   页码 228-234 doi: 10.1007/s11783-010-0022-7

摘要： Aerobic composting is a method for the sanitary disposal of human feces as is used in bio-toilet systems. As the products of composting can be utilized as a fertilizer, it would be beneficial if the composting conditions could be more precisely controlled for the retention of fecal nitrogen as long as possible in the compost. In this study, batch experiments were conducted using a closed aerobic thermophilic composting reactor with sawdust as the bulk matrix to simulate the condition of a bio-toilet for the sanitary disposal of human feces. Attention was paid to the characteristics of nitrogen transformation. Under the controlled conditions of temperature at 60°C, moisture content at 60%, and a continuous air supply, more than 70% fecal organic removal was obtained, while merely 17% fecal nitrogen loss was observed over a two-week composting period. The nitrogen loss was found to occur mainly in the first 24 h with the rapid depletion of inorganic nitrogen but with an almost unchanged organic nitrogen content. The fecal NH–N which was the main component of the inorganic nitrogen (>90%) decreased rapidly in the first day, decreased at a slower rate over the following days, and finally disappeared entirely. The depletion of NH–N was accompanied by the accumulation of NH gas in the ammonia absorber connected to the reactor. A mass balance between the exhausted NH gas and the fecal NH–N content in the first 24 hours indicated that the conversion of ammonium into gaseous ammonia was the main reason for nitrogen loss. Thermophilic composting could be considered as a way to keep a high organic nitrogen content in the compost for better utilization as a fertilizer.

关键词： nitrogen retention     composting reactor     human feces     aerobic     thermophilic     fertilizer    

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Size-controllable synthesis of monodispersed nitrogen-doped carbon nanospheres from polydopamine for high-rate

《化学科学与工程前沿（英文）》 2023年 第17卷 第11期   页码 1788-1800 doi: 10.1007/s11705-023-2326-8

摘要： Monodispersed nitrogen-doped carbon nanospheres with tunable particle size (100–230 nm) were synthesized via self-polymerization of biochemical dopamine in the presence of hexamethylenetetramine as a buffer and F127 as a size controlling agent. Hexamethylenetetramine can mildly release NH3, which in turn initiates the polymerization reaction of dopamine. The carbon nanospheres obtained exhibited a significant energy storage capability of 265 F·g–1 at 0.5 A·g–1 and high-rate performance of 82% in 6 mol·L–1 KOH (20 A·g–1), which could be attributed to the presence of abundant micro-mesoporous structure, doped nitrogen functional groups and the small particle size. Moreover, the fabricated symmetric supercapacitor device displayed a high stability of 94% after 5000 cycles, revealing the considerable potential of carbon nanospheres as electrode materials for energy storage.

关键词： carbon nanospheres     size-controlled     nitrogen-doped     high-rate     supercapacitors    

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标题 作者 时间 类型 操作

Effects of operating conditions on membrane charge property and nanofiltration

Li XU, Li-Shun DU, Jing HE

期刊论文

Modelling the thresholds of nitrogen/phosphorus concentration and hydraulic retention time for bloom

期刊论文

Effects of hydraulic retention time on nitrification activities and population dynamics of a conventional

Hongyan LI, Yu ZHANG, Min YANG, Yoichi KAMAGATA

期刊论文

Sustaining health workforce recruitment and retention in township hospitals: a survey on 110 directors

null

期刊论文

EFFECT OF EXOGENOUS ADDITIVES ON HEAVY METAL PASSIVATION AND NITROGEN RETENTION IN PIG MANURE COMPOSTING

期刊论文

Bio-based Waterborne Poly(Vanillin-Butyl Acrylate)/MXene Coatings for Leather with Desired Warmth Retention

Jianzhong Ma,Li Ma,Lei Zhang,Wenbo Zhang,Qianqian Fan,Buxing Han,

期刊论文

Influence of hydraulic retention time on behavior of antibiotics and antibiotic resistance genes in aerobic

Jie Liao, Chaoxiang Liu, Lin Liu, Jie Li, Hongyong Fan, Jiaqi Ye, Zhichao Zeng

期刊论文

Effects of hydraulic retention time on net present value and performance in a membrane bioreactor treating

Dawei Yu, Jianxing Wang, Libin Zheng, Qianwen Sui, Hui Zhong, Meixue Cheng, Yuansong Wei

期刊论文

Cotransfecting norepinephrine transporter and vesicular monoamine transporter 2 genes for increased retention

null

期刊论文

The combined effects of biomass and temperature on maximum specific ammonia oxidation rate in domestic

期刊论文

Use of float consumption rate in resource leveling of construction projects

Atilla DAMCI, Gul POLAT, Firat Dogu AKIN, Harun TURKOGLU

期刊论文

Effect of biochar amendment on soil’s retention capacity for estrogenic hormones from poultry manure

Sukhjot MANN, Zhiming QI, Shiv O. PRASHER, Lanhai LI, Dongwei GUI, Qianjing JIANG

期刊论文

Effect of loading rate on shear strength parameters of mechanically and biologically treated waste

期刊论文

Nitrogen-retaining property of compost in an aerobic thermophilic composting reactor for the sanitary disposal of human feces

Fan BAI, Xiaochang WANG,

期刊论文

Size-controllable synthesis of monodispersed nitrogen-doped carbon nanospheres from polydopamine for high-rate

期刊论文