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Evaluation of the k-nearest neighbor method for forecasting the influent characteristics of wastewater

Minsoo KIM,Yejin KIM,Hyosoo KIM,Wenhua PIAO,Changwon KIM

《环境科学与工程前沿(英文)》 2016年 第10卷 第2期   页码 299-310 doi: 10.1007/s11783-015-0825-7

摘要: The k-nearest neighbor (k-NN) method was evaluated to predict the influent flow rate and four water qualities, namely chemical oxygen demand (COD), suspended solid (SS), total nitrogen (T-N) and total phosphorus (T-P) at a wastewater treatment plant (WWTP). The search range and approach for determining the number of nearest neighbors (NNs) under dry and wet weather conditions were initially optimized based on the root mean square error (RMSE). The optimum search range for considering data size was one year. The square root-based (SR) approach was superior to the distance factor-based (DF) approach in determining the appropriate number of NNs. However, the results for both approaches varied slightly depending on the water quality and the weather conditions. The influent flow rate was accurately predicted within one standard deviation of measured values. Influent water qualities were well predicted with the mean absolute percentage error (MAPE) under both wet and dry weather conditions. For the seven-day prediction, the difference in predictive accuracy was less than 5% in dry weather conditions and slightly worse in wet weather conditions. Overall, the k-NN method was verified to be useful for predicting WWTP influent characteristics.

关键词: influent wastewater     prediction     data-driven model     k-nearest neighbor method (k-NN)    

Characteristic and correlation analysis of influent and energy consumption of wastewater treatment plants

Luxi Zou, Huaibo Li, Shuo Wang, Kaikai Zheng, Yan Wang, Guocheng Du, Ji Li

《环境科学与工程前沿(英文)》 2019年 第13卷 第6期 doi: 10.1007/s11783-019-1167-7

摘要: Poor biodegradability and insufficient carbon source are discovered from influent. Influent indices presented positively normal distribution or skewed distribution. Average energy consumption of WWTPs in Taihu Basin was as high as 0.458 kWh/m3. Energy consumption increases with the increase in influent volume and COD reduction. The total energy consumption decreases with the NH3-N reduction. The water quality and energy consumption of wastewater treatment plants (WWTPs) in Taihu Basin were evaluated on the basis of the operation data from 204 municipal WWTPs in the basin by using various statistical methods. The influent ammonia nitrogen (NH3-N) and total nitrogen (TN) of WWTPs in Taihu Basin showed normal distribution, whereas chemical oxygen demand (COD), biochemical oxygen demand (BOD5), suspended solid (SS), and total phosphorus (TP) showed positively skewed distribution. The influent BOD5/COD was 0.4%–0.6%, only 39.2% SS/BOD5 exceeded the standard by 36.3%, the average BOD5/TN was 3.82, and the probability of influent BOD5/TP>20 was 82.8%. The average energy consumption of WWTPs in Taihu Basin in 2017 was 0.458 kWh/m3. The specific energy consumption of WWTPs with a daily treatment capacity of more than 5 × 104 m3 in Taihu Basin was stable at 0.33 kWh/m3. A power function relationship was observed between the reduction in COD and NH3-N and the specific energy consumption of pollutant reduction, and the higher the pollutant reduction is, the lower the specific energy consumption of pollutant reduction presents. In addition, a linear relationship existed between the energy consumption of WWTPs and the specific energy consumption of influent volume and pollutant reduction. Therefore, upgrading and operation with less energy consumption of WWTPs is imperative and the suggestions for Taihu WWTPs based on stringent discharge standard are proposed in detail.

关键词: Taihu Basin     Wastewater treatment plant     Influent characteristics     Energy consumption evaluation     Specific energy consumption     SPSS correlation analysis    

Distribution, characteristics and daily fluctuations of microplastics throughout wastewater treatment

《环境科学与工程前沿(英文)》 2022年 第16卷 第1期   页码 6-6 doi: 10.1007/s11783-021-1440-4

摘要:

• MPs were analyzed throughout three WWTPs with mixed domestic–industrial influents.

关键词: Microplastic     Wastewater treatment plant     Mixed domestic-industrial influent     Characteristic     Daily fluctuation    

Influence of influent on anaerobic ammonium oxidation in an Expanded Granular Sludge Bed-Biological Aerated

Daijun ZHANG, Cui BAI, Ting TANG, Qing YANG

《环境科学与工程前沿(英文)》 2011年 第5卷 第2期   页码 291-297 doi: 10.1007/s11783-010-0270-6

摘要: Shortcut nitrification-denitrification, anaerobic ammonium oxidation (ANAMMOX), and methanogenesis have been successfully coupled in an Expanded Granular Sludge Bed-Biological Aerated Filter (EGSB-BAF) integrated system. As fed different synthetic wastewater with chemical oxygen demand (COD) of 300–1200 mg·L and of 30–120 mg·L at the outer recycle ratio of 200%, the influence of influent on ANAMMOX in the integrated system was investigated in this paper. The experimental results showed that higher COD concentration caused an increase in denitrification and methanogenesis but a decrease in ANAMMOX; however, when an influent with the low concentration of COD was used, the opposite changes could be observed. Higher influent concentration favored ANAMMOX when the COD concentration of influent was fixed. Therefore, low ratio would decrease competition for nitrite between ANAMMOX and denitrification, which was favorable for reducing the negative effect of organic COD on ANAMMOX. The good performance of the integrated system indicated that the bacterial community of denitrification, ANAMMOX, and methanogenesis could be dynamically maintained in the sludge of EGSB reactor for a certain range of influent.

关键词: Expanded Granular Sludge Bed-Biological Aerated Filter (EGSB-BAF) integrated system     the influence of influent     anaerobic ammonium oxidation (ANAMMOX)     shortcut nitrification-denitrification     methano-genesis    

Short-term prediction of the influent quantity time series of wastewater treatment plant based on a chaos

LI Xiaodong, ZENG Guangming, HUANG Guohe, LI Jianbing, JIANG Ru

《环境科学与工程前沿(英文)》 2007年 第1卷 第3期   页码 334-338 doi: 10.1007/s11783-007-0057-6

摘要: By predicting influent quantity, a wastewater treatment plant (WWTP) can be well controlled. The nonlinear dynamic characteristic of WWTP influent quantity time series was analyzed, with the assumption that the series was predictable. Based on this, a short-term forecasting chaos neural network model of WWTP influent quantity was built by phase space reconstruction. Reasonable forecasting results were achieved using this method.

关键词: nonlinear     reconstruction     WWTP influent     characteristic     Reasonable forecasting    

Short-term prediction of influent flow rate and ammonia concentration in municipal wastewater treatment

Shuai MA, Siyu ZENG, Xin DONG, Jining CHEN, Gustaf OLSSON

《环境科学与工程前沿(英文)》 2014年 第8卷 第1期   页码 128-136 doi: 10.1007/s11783-013-0598-9

摘要: The prediction of the influent load is of great importance for the improvement of the control system to a large wastewater treatment plant. A systematic data analysis method is presented in this paper in order to estimate and predict the periodicity of the influent flow rate and ammonia (NH ) concentrations: 1) data filtering using wavelet decomposition and reconstruction; 2) typical cycle identification using power spectrum density analysis; 3) fitting and prediction model establishment based on an autoregressive model. To give meaningful information for feedforward control systems, predictions in different time scales are tested to compare the corresponding predicting accuracy. Considering the influence of the rainfalls, a linear fitting model is derived to estimate the relationship between flow rate trend and rain events. Measurements used to support coefficient fitting and model testing are acquired from two municipal wastewater treatment plants in China. The results show that 1) for both of the two plants, the periodicity affects the flow rate and NH concentrations in different cycles (especially cycles longer than 1 day); 2) when the flow rate and NH concentrations present an obvious periodicity, the decreasing of prediction accuracy is not distinct with increasing of the prediction time scales; 3) the periodicity influence is larger than rainfalls; 4) the rainfalls will make the periodicity of flow rate less obvious in intensive rainy periods.

关键词: influent load prediction     wavelet de-noising     power spectrum density     autoregressive model     time-frequency analysis     wastewater treatment    

Process evaluation of an alternating aerobic-anoxic process applied in a sequencing batch reactor for nitrogen removal

ZENG Wei, PENG Yongzhen, WANG Shuying

《环境科学与工程前沿(英文)》 2007年 第1卷 第1期   页码 28-32 doi: 10.1007/s11783-007-0005-5

摘要: In order to improve the nitrogen removal efficiency and save operational cost, the feasibility of the alternating aerobic-anoxic process (AAA process) applied in a sequencing batch reactor (SBR) system for nitrogen removal was investigated. Under sufficient influent alkalinity, the AAA process did not have an advantage over one aerobicanoxic (OAA) cycle on treatment efficiency because microorganisms had an adaptive stage at the alternating aerobic-anoxic transition, which would prolong the total cycling time. On the contrary, the AAA process made the system control more complicated. Under deficient influent alkalinity, when compared to OAA, the AAA process improved treatment efficiency and effluent quality with NH-N in the effluent below the detection limit. In the nitrification, the average stoichiometric ratio between alkalinity consumption and ammonia oxidation is calculated to be 7.07 mg CaCO/mg NH-N. In the denitrification, the average stoichiometric ratio between alkalinity production and NO-N reduction is about 3.57 mg CaCO/mg NO-N. As a result, half of the alkalinity previously consumed during the aerobic nitrification was recovered during the subsequent anoxic denitrification period. That was why the higher treatment efficiency in the AAA process was achieved without the supplement of bicarbonate alkalinity. If the lack of alkalinity in the influent was less than 1/3 of that needed, there is no need for external alkalinity addition and treatment efficiency was the same as that under sufficient influent alkalinity. Even if the lack of alkalinity in the influent was more than 1/3 of that needed, the AAA process was an optimal strategy because it reduced the external alkalinity addition and saved on operational cost.

关键词: bicarbonate alkalinity     sufficient influent     influent alkalinity     detection     alkalinity production    

Nitrate removal to its fate in wetland mesocosm filled with sponge iron: Impact of influent COD/N ratio

Zhihao Si, Xinshan Song, Xin Cao, Yuhui Wang, Yifei Wang, Yufeng Zhao, Xiaoyan Ge, Awet Arefe Tesfahunegn

《环境科学与工程前沿(英文)》 2020年 第14卷 第1期 doi: 10.1007/s11783-019-1183-7

摘要: CW-Fe allowed a high-performance of NO3‒-N removal at the COD/N ratio of 0. Higher COD/N resulted in lower chem-denitrification and higher bio-denitrification. The application of s-Fe0 contributed to TIN removal in wetland mesocosm. s-Fe0 changed the main denitrifiers in wetland mesocosm. Sponge iron (s-Fe0) is a porous metal with the potential to be an electron donor for denitrification. This study aims to evaluate the feasibility of using s-Fe0 as the substrate of wetland mesocosms. Here, wetland mesocosms with the addition of s-Fe0 particles (CW-Fe) and a blank control group (CW-CK) were established. The NO3‒-N reduction property and water quality parameters (pH, DO, and ORP) were examined at three COD/N ratios (0, 5, and 10). Results showed that the NO3‒-N removal efficiencies were significantly increased by 6.6 to 58.9% in the presence of s-Fe0. NH4+-N was mainly produced by chemical denitrification, and approximately 50% of the NO3‒-N was reduced to NH4+-N, at the COD/ratio of 0. An increase of the influent COD/N ratio resulted in lower chemical denitrification and higher bio-denitrification. Although chemical denitrification mediated by s-Fe0 led to an accumulation of NH4+-N at COD/N ratios of 0 and 5, the TIN removal efficiencies increased by 4.5%‒12.4%. Moreover, the effluent pH, DO, and ORP values showed a significant negative correlation with total Fe and Fe (II) (P<0.01). High-throughput sequencing analysis indicated that Trichococcus (77.2%) was the most abundant microorganism in the CW-Fe mesocosm, while Thauera, Zoogloea, and Herbaspirillum were the primary denitrifying bacteria. The denitrifiers, Simplicispira, Dechloromonas, and Denitratisoma, were the dominant bacteria for CW-CK. This study provides a valuable method and an improved understanding of NO3‒-N reduction characteristics of s-Fe0 in a wetland mesocosm.

关键词: Sponge iron     Wetland mesocosm     Electronic donor     Denitrification     COD/N ratio    

Recent progress in hydrodynamic characteristics research and application of annular centrifugal extractors

《化学科学与工程前沿(英文)》 2022年 第16卷 第6期   页码 854-873 doi: 10.1007/s11705-022-2156-0

摘要: The annular centrifugal extractor (ACE) integrates mixing and separation. It has been widely used in many industrial fields because of its low residence time, compact structure, and high mass transfer efficiency. Most of the literature has focused on flow instabilities, flow visualization, and computational fluid dynamics simulations. More recently, research on hydrodynamic behavior and structural optimization has received widespread attention. With the development of ACE technology, applications have been broadened into several new areas. Hence, this paper reviews research progress regarding ACE in terms of hydrodynamic characteristics and the structural improvements. The latest applications covering hydrometallurgy, nuclear fuel reprocessing, bio-extraction, catalytic reaction, and wastewater treatment are presented. We also evaluate future work in droplet breakup and coalescence mechanisms, structural improvements specific to different process requirements, scaling-up methods, and stability and reliability after scaling-up.

关键词: annular centrifugal extractor     hydrodynamic characteristics     structure optimization     the latest application    

Clinical characteristics and outcomes of biopsy-proven diabetic nephropathy

null

《医学前沿(英文)》 2017年 第11卷 第3期   页码 386-392 doi: 10.1007/s11684-017-0574-z

摘要:

Kidney damage is common in patients with diabetes mellitus (DM). However, whether the type of kidney damage can be reliably diagnosed using clinical data alone remains unclear. Predictive factors for diabetic nephropathy (DN) outcomes are also poorly understood. In this study, the clinical manifestations of 111 cases of biopsy-proven DN were described, and the clinical and pathological parameters of patients with different DN outcomes were compared. Results showed that long DM duration (>10 years in 32.4% of patients), severe proteinuria (62.2%), and renal dysfunction (estimated glomerular filtration rate [eGFR]<60 mL/(min·1.73 m2)) (52.3%) did not accurately indicate whether the condition of these patients progressed to DN. Hematuria (48.6%) failed to specify either DN or nondiabetic renal disease. Diabetic retinopathy (78.4%) was a crucial complication in patients with DN. Kaplan–Meier analysis revealed that the renal survival of 53 patients who were diagnosed with DN and were followed up was not significantly associated with glomerular classification (P>0.05). Cox’s regression analysis demonstrated that renal survival time was significantly influenced by sex (b= 1.394, P= 0.038), hematuria (b= 0.036, P= 0.029), and eGFR (b= −0.039, P= 0.002) but was not significantly affected by age, 24 h urinary protein excretion, or glomerular classification (P>0.05). In conclusion, the clinical characteristics of DN vary, and renal biopsy is necessary to determine renal damage patterns. Sex, hematuria, and the eGFR may affect DN outcomes, whereas the glomerular classification may not.

关键词: diabetic nephropathy     clinical characteristics     renal biopsy     outcomes    

Obesity in China: its characteristics, diagnostic criteria, and implications

null

《医学前沿(英文)》 2015年 第9卷 第2期   页码 129-133 doi: 10.1007/s11684-015-0387-x

Anaerobic treatment of wastewater containing methanol in up-flow anaerobic sludge bed (UASB) reactor

LIN Yishan, HE Yanling, MENG Zhuo, YANG Shucheng

《环境科学与工程前沿(英文)》 2008年 第2卷 第2期   页码 241-246 doi: 10.1007/s11783-008-0040-x

摘要: The direct conversion of methanol into methane is the main process in anaerobic treatment of methanol containing wastewater. However, acetic acid can also be produced from methanol theoretically, which may probably result in an abrupt pH drop and deteriorate the anaerobic process. Therefore, it is interesting to know what would really happen in an anaerobic reactor treating methanol wastewater. In this study, an up-flow anaerobic sludge bed (UASB) reactor treating methanol wastewater was operated. The chemical oxygen demand (COD), acetic acid and pH of the effluent were monitored at different loadings and influent alkalinity. The results showed that the anaerobic reactor could be operated steadily at as low as 119 mg/L of influent alkalinity and high organic loading rate with no obvious pH drops. Volatile fatty acids accumulation was not observed even at strong shock loadings. The microorganisms in the sludge at the end of the test became homogeneous in morphology, which were mainly spherical or spheroidal in shape.

关键词: homogeneous     spherical     influent alkalinity     process     anaerobic treatment    

Obesity-related glomerulopathy: pathogenesis, pathologic, clinical characteristics and treatment

null

《医学前沿(英文)》 2017年 第11卷 第3期   页码 340-348 doi: 10.1007/s11684-017-0570-3

摘要:

In light of the rapid increase in the number of obesity incidences worldwide, obesity has become an independent risk factor for chronic kidney disease. Obesity-related glomerulopathy (ORG) is characterized by glomerulomegaly in the presence or absence of focal and segmental glomerulosclerosis lesions. IgM and complement 3 (C3) nonspecifically deposit in lesions without immune-complex-type deposits during ORG immunofluorescence. ORG-associated glomerulomegaly and focal and segmental glomerulosclerosis can superimpose on other renal pathologies. The mechanisms under ORG are complex, especially hemodynamic changes, inflammation, oxidative stress, apoptosis, and reduced functioning nephrons. These mechanisms synergize with obesity to induce end-stage renal disease. A slow increase of subnephrotic proteinuria (<3.5 g/d) is the most common clinical manifestation of ORG. Several treatment methods for ORG have been developed. Of these methods, renin–angiotensin–aldosterone system blockade and weight loss are proven effective. Targeting mitochondria may offer a novel strategy for ORG therapy. Nevertheless, more research is needed to further understand ORG.

关键词: obesity-related glomerulopathy     pathogenesis     pathologic     clinical characteristics    

Dynamic characteristics of molten droplets and hot particles falling in liquid pool

Liangxing LI, Weimin MA, Huixiong LI, Tingkuan CHEN,

《能源前沿(英文)》 2010年 第4卷 第2期   页码 246-251 doi: 10.1007/s11708-009-0077-y

摘要: The dynamic characteristics of molten droplets and hot particles at the very beginning of their fall into coolant pools are presented. The falling course of a single droplet or a single hot particle was recorded by a high-speed camera and a curve of velocity . time was obtained. Emphasis was placed on the effects of the droplet’s size and temperature, the coolant’s temperature and properties, and the droplet’s physical properties on the moving behavior. The results for the all cases showed that the velocity of a falling droplet/particle decreased rapidly but rebounded shortly, at the beginning of droplet/particle falling in the coolant. Following such a V-shaped evolution in velocity, the droplet/particle slows down gradually to a comparatively steady velocity. An increase in either coolant temperature or droplet temperature results in a larger velocity variation in the “J-region”, but a smaller deceleration when it moves out of the “J-region”. The elevated volatility of a coolant leads to a steeper deceleration in the “J-region” and beyond. The bigger size of a particle leads to a greater velocity variation in the “J-region” and terminal velocity. A high melting point and thermal conductivity as well as lower heat capacity contribute to dramatic variation in the “J-region” and low terminal velocity.

关键词: dynamic characteristics     molten droplets     high-temperature particles     fuel and coolant interactions    

Combustion characteristics and kinetics of bio-oil

Ruixia ZHANG, Zhaoping ZHONG, Yaji HUANG

《化学科学与工程前沿(英文)》 2009年 第3卷 第2期   页码 119-124 doi: 10.1007/s11705-009-0068-x

摘要: The combustion characteristics of bio-oils derived from rice husk and corn were studied by thermogravimetry analysis. According to the thermogravimetry (TG), differential thermogravimetry (DTG) and differential thermal analysis (DTA) curves of bio-oils in air and nitrogen atmosphere, we analyzed the combustion characteristics of different kinds of bio-oils in different atmospheres and worked out the combustion kinetics parameters of the bio-oil, providing reliable base data for the burning of bio-oil. The thermogravimetry indicated that the combustion process of bio-oil was divided into three stages. At the same time, the combustion process can be described by different order reaction models, and with the method of Coats-Redfern, the activation energy and frequency factor of different kinds of bio-oils were obtained.

关键词: bio-oil     combustion characteristics     combustion kinetics    

标题 作者 时间 类型 操作

Evaluation of the k-nearest neighbor method for forecasting the influent characteristics of wastewater

Minsoo KIM,Yejin KIM,Hyosoo KIM,Wenhua PIAO,Changwon KIM

期刊论文

Characteristic and correlation analysis of influent and energy consumption of wastewater treatment plants

Luxi Zou, Huaibo Li, Shuo Wang, Kaikai Zheng, Yan Wang, Guocheng Du, Ji Li

期刊论文

Distribution, characteristics and daily fluctuations of microplastics throughout wastewater treatment

期刊论文

Influence of influent on anaerobic ammonium oxidation in an Expanded Granular Sludge Bed-Biological Aerated

Daijun ZHANG, Cui BAI, Ting TANG, Qing YANG

期刊论文

Short-term prediction of the influent quantity time series of wastewater treatment plant based on a chaos

LI Xiaodong, ZENG Guangming, HUANG Guohe, LI Jianbing, JIANG Ru

期刊论文

Short-term prediction of influent flow rate and ammonia concentration in municipal wastewater treatment

Shuai MA, Siyu ZENG, Xin DONG, Jining CHEN, Gustaf OLSSON

期刊论文

Process evaluation of an alternating aerobic-anoxic process applied in a sequencing batch reactor for nitrogen removal

ZENG Wei, PENG Yongzhen, WANG Shuying

期刊论文

Nitrate removal to its fate in wetland mesocosm filled with sponge iron: Impact of influent COD/N ratio

Zhihao Si, Xinshan Song, Xin Cao, Yuhui Wang, Yifei Wang, Yufeng Zhao, Xiaoyan Ge, Awet Arefe Tesfahunegn

期刊论文

Recent progress in hydrodynamic characteristics research and application of annular centrifugal extractors

期刊论文

Clinical characteristics and outcomes of biopsy-proven diabetic nephropathy

null

期刊论文

Obesity in China: its characteristics, diagnostic criteria, and implications

null

期刊论文

Anaerobic treatment of wastewater containing methanol in up-flow anaerobic sludge bed (UASB) reactor

LIN Yishan, HE Yanling, MENG Zhuo, YANG Shucheng

期刊论文

Obesity-related glomerulopathy: pathogenesis, pathologic, clinical characteristics and treatment

null

期刊论文

Dynamic characteristics of molten droplets and hot particles falling in liquid pool

Liangxing LI, Weimin MA, Huixiong LI, Tingkuan CHEN,

期刊论文

Combustion characteristics and kinetics of bio-oil

Ruixia ZHANG, Zhaoping ZHONG, Yaji HUANG

期刊论文