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Comparison between inhibitor and uncoupler for minimizing excess sludge production of an activated sludge process

CHEN Guowei, XI Pengge, XU Deqian, YU Hanqing

《环境科学与工程前沿（英文）》 2007年 第1卷 第1期   页码 63-66 doi: 10.1007/s11783-007-0012-6

摘要： In order to study the minimization of excess sludge production, the reduction in the excess sludge production in the presence of an inhibitor and uncoupler was studied in this work. The experimental results show that such an addition could effectively reduce the production of excess sludge. With the energy uncoupling model established in this work, energy uncoupling coefficient () was used to evaluate the reduction in excess sludge production. The energy uncoupling coefficients in the presence of dinitrophenol (dNP), Zn, and Cu was 0.75, 0.46, and 0.18, respectively. The analysis demonstrated that energy spilling occurred in the presence of dNP, and that dNP was an effective uncoupler for reducing the production of excess activated sludge without affecting the microbial respiration activity.

关键词： uncoupling coefficient     Cu     minimization     presence     uncoupling    

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Co-application of energy uncoupling and ultrafiltration in sludge treatment: Evaluations of sludge reduction

An Ding, Yingxue Zhao, Zhongsen Yan, Langming Bai, Haiyang Yang, Heng Liang, Guibai Li, Nanqi Ren

《环境科学与工程前沿（英文）》 2020年 第14卷 第4期 doi: 10.1007/s11783-020-1238-9

摘要： Effects of metabolic uncouplers addition on sludge reduction were carried out. TCS addition effectively inhibited ATP synthesis and reduced sludge yield. The effluent quality such as TOC and ammonia deteriorated but not significantly. Suitable dosage retarded biofouling during sludge water recovery by UF membrane. Energy uncoupling is often used for sludge reduction because it is easy to operate and does not require a significant amount of extra equipments (i.e. no additional tank required). However, over time the supernatant extracted using this method can deteriorate, ultimately requiring further treatment. The purpose of this study was to determine the effect of using a low-pressure ultrafiltration membrane process for sludge water recovery after the sludge had undergone an energy uncoupling treatment (using 3,3′,4′,5-tetrachlorosalicylanilide (TCS)). Energy uncoupling was found to break apart sludge floc by reducing extracellular polymeric substances (EPS) and adenosine triphosphate (ATP) content. Analysis of supernatant indicated that when energy uncoupling and membrane filtration were co-applied and the TCS dosage was below 30 mg/L, there was no significant deterioration in organic component removal. However, ammonia and phosphate concentrations were found to increase as the concentration of TCS added increased. Additionally, due to low sludge concentrations and EPS contents, addition of 30–60 mg/L TCS during sludge reduction increased the permeate flux (two times higher than the control) and decreased the hydraulic reversible and cake layer resistances. In contrast, high dosage of TCS aggravated membrane fouling by forming compact fouling layers. In general, this study found that the co-application of energy uncoupling and membrane filtration processes represents an effective alternative method for simultaneous sludge reduction and sludge supernatant recovery.

关键词： Sludge reduction     Energy uncoupling     Ultrafiltration membrane     Membrane fouling    

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RETRACTED ARTICLE: Momentum exchange coefficient for two jet flows mixing in a tee junction

《化学科学与工程前沿（英文）》 2023年 第17卷 第12期   页码 2161-2161 doi: 10.1007/s11705-009-0143-3

摘要： RETRACTED ARTICLE: Momentum exchange coefficient for two jet flows mixing in a tee junction

关键词： tee junction     Momentum exchange coefficient     RETRACTED    

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Experimental study of heat transfer coefficient with rectangular baffle fin of solar air heater

Foued CHABANE,Nesrine HATRAF,Noureddine MOUMMI

《能源前沿（英文）》 2014年 第8卷 第2期   页码 160-172 doi: 10.1007/s11708-014-0321-y

摘要： This paper presents an experimental analysis of a single pass solar air collector with, and without using baffle fin. The heat transfer coefficient between the absorber plate and air can be considerably increased by using artificial roughness on the bottom plate and under the absorber plate of a solar air heater duct. An experimental study has been conducted to investigate the effect of roughness and operating parameters on heat transfer. The investigation has covered the range of Reynolds number from 1259 to 2517 depending on types of the configuration of the solar collectors. Based on the experimental data, values of Nusselt number have been determined for different values of configurations and operating parameters. To determine the enhancement in heat transfer and increment in thermal efficiency, the values of Nusselt have been compared with those of smooth duct under similar flow conditions.

关键词： Nusselt number     flow rate     heat transfer     heat transfer coefficient     thermal efficiency     forced convection    

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A photolysis coefficient for characterizing the response of aqueous constituents to photolysis

David R. HOKANSON,Ke LI,R. Rhodes TRUSSELL

《环境科学与工程前沿（英文）》 2016年 第10卷 第3期   页码 428-437 doi: 10.1007/s11783-015-0780-3

摘要： UV photolysis and UV based advanced oxidation processes (AOPs) are gaining more and more attention for drinking water treatment. Quantum yield ( ) and molar absorption coefficient ( ) are the two critical parameters measuring the effectiveness of photolysis of a compound. The product of the two was proposed as a fundamental measure of a constituent’s amenability to transformation by photolysis. It was shown that this product, named the photolysis coefficient, , can be determined using standard bench tests and captures the properties that govern a constituent’s transformation when exposed to light. The development showed the photolysis coefficient to be equally useful for microbiological, inorganic and organic constituents. Values of calculated by the authors based on quantum yield and molar absorption coefficient data from the literature were summarized. Photolysis coefficients among microorganisms ranged from 8500 to more than 600000 and are far higher than for inorganic and organic compounds, which varied over a range of approximately 10 to 1000 and are much less sensitive to UV photolysis than the microorganisms.

关键词： UV photolysis     disinfection     advanced oxidation     N-nitrosodimethylamine     quantum yield     absorption coefficient    

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Effect of heat transfer coefficient of steam turbine rotor on thermal stress field under off-design condition

Jie GUO,Danmei XIE,Hengliang ZHANG,Wei JIANG,Yan ZHOU

《能源前沿（英文）》 2016年 第10卷 第1期   页码 57-64 doi: 10.1007/s11708-015-0385-3

摘要： The precise calculation of temperature and thermal stress field of steam turbine rotor under off-design conditions is of paramount significance for safe and economic operation, in which an accurate calculation of heat transfer (HT) coefficient plays a decisive role. HT coefficient changes dramatically along with working conditions. First, a finite element analysis of rotor model, applied with ordinary rotor materials, has been conducted to investigate the temperature and thermal stress difference along with the change of HT coefficient from 20 W/(m ·°C) to 20000 W/(m ·°C). Next, the differentiation between existing empirical formulas has been analyzed from the aspect of physical significance of non-dimension parameters. Finally, a verifying case of the cold startup of a 1000MW unit has been proceeded. The result shows that the accuracy of coefficient calculation when steam parameters are low has a greater influence on that of rotor temperature and thermal stress, which means a precise empirical HT coefficient formula, like the Sarkar formula is strongly recommended. When steam parameters are high and HT coefficient is larger than 10 W/(m ·°C), there will be barely any influence on the calculation of thermal stress. This research plays a constructive role in the calculation and analysis of thermal stress.

关键词： steam turbine     rotor     thermal stress     heat transfer coefficient     empirical formula    

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Dimensionality reduction and prediction of soil consolidation coefficient using random forest coupling

Hai-Bang LY; Huong-Lan Thi VU; Lanh Si HO; Binh Thai PHAM

《结构与土木工程前沿（英文）》 2022年 第16卷 第2期   页码 224-238 doi: 10.1007/s11709-022-0812-6

摘要： The consolidation coefficient of soil (Cv) is a crucial parameter used for the design of structures leaned on soft soi. In general, the Cv is determined experimentally in the laboratory. However, the experimental tests are time-consuming as well as expensive. Therefore, researchers tried several ways to determine Cv via other simple soil parameters. In this study, we developed a hybrid model of Random Forest coupling with a Relief algorithm (RF-RL) to predict the Cv of soil. To conduct this study, a database of soil parameters collected from a case study region in Vietnam was used for modeling. The performance of the proposed models was assessed via statistical indicators, namely Coefficient of determination (R2), Root Mean Squared Error (RMSE), and Mean Absolute Error (MAE). The proposal models were constructed with four sets of soil variables, including 6, 7, 8, and 13 inputs. The results revealed that all models performed well with a high performance (R2 > 0.980). Although the RF-RL model with 13 variables has the highest prediction accuracy ( R2 = 0.9869), the difference compared with other models was negligible (i.e., R2 = 0.9824, 0.9850, 0.9825 for the cases with 6, 7, 8 inputs, respectively). Thus, it can be concluded that the hybrid model of RF-RL can be employed to predict Cv based on the basic soil parameters.

关键词： soil consolidation coefficient     machine learning     random forest     Relief    

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Developing the QSPR model for predicting the storage lipid/water distribution coefficient of organic

Miao Li, Jian Li, Yuchen Lu, Cenyang Han, Xiaoxuan Wei, Guangcai Ma, Haiying Yu

《环境科学与工程前沿（英文）》 2021年 第15卷 第2期 doi: 10.1007/s11783-020-1316-z

摘要： Abstract • A predictive model for storage lipid/water distribution coefficient was developed. • The model yields outstanding fitting performance, robustness, and predictive ability. • Hydrophobic and electrostatic interactions and molecular size dominate log Klip/w. • The model can be used in a wide application domain to predict log Klip/w values. The distribution of organic compounds in stored lipids affects their migration, transformation, bioaccumulation, and toxicity in organisms. The storage lipid/water distribution coefficient (log Klip/w) of organic chemicals, which quantitatively determines such distribution, has become a key parameter to assist their ecological security and health risk. Due to the impossibility to measure Klip/w values for a huge amount of chemicals, it is necessary to develop predictive approaches. In this work, a quantitative structure-property relationship (QSPR) model for estimating log Klip/w values of small organic compounds was constructed based on 305 experimental log Klip/w values. Quantum chemical descriptors and n-octanol/water partitioning coefficient were employed to characterize the intermolecular interactions that dominate log Klip/w values. The hydrophobic and electrostatic interactions and molecular size have been found to play important roles in governing the distribution of chemicals between lipids and aqueous phases. The regression (R2 = 0.959) and validation (Q2 = 0.960) results indicate good fitting performance and robustness of the developed model. A comparison with the predictive performance of other commercial software further proves the higher accuracy and stronger predictive ability of the developed Klip/w predictive model. Thus, it can be used to predict the Klip/w values of cycloalkanes, long-chain alkanes, halides (with fluorine, chlorine, and bromine as substituents), esters (without phosphate groups), alcohols (without methoxy groups), and aromatic compounds.

关键词： Storage lipid/water distribution coefficient     log Klip/w     Organic compounds     QSPR     Quantum chemical descriptors    

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Heat transfer coefficient of wheel rim of large capacity steam turbines

SHI Jinyuan, DENG Zhicheng, YANG Yu, JUN Ganwen

《能源前沿（英文）》 2008年 第2卷 第1期   页码 20-24 doi: 10.1007/s11708-008-0015-4

摘要： A way of calculating the overall equivalent heat transfer coefficient of wheel rims of large capacity steam turbines is presented. The method and formula to calculate the mean forced convection heat-transfer coefficient of the surface of the blade and for the bottom wall of the blade passage, are introduced. The heat transmission from the blade to the rim was simplified by analogy to heat transmission in the fins. A fin heat transfer model was then used to calculate the equivalent heat transfer coefficient of the blade passage. The overall equivalent heat transfer coefficient of the wheel rim was then calculated using a cylindrical surface model. A practical calculation example was presented. The proposed method helps determine the heat transfer boundary conditions in finite element analyses of temperature and thermal stress fields of steam turbine rotors.

关键词： convection heat-transfer     capacity     heat-transfer coefficient     bottom     transmission    

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Diagnosis method based on wavelet coefficient scale relativity correlation dimension for fault

GU Junjie, TIAN Jin, PENG Xuezhi

《能源前沿（英文）》 2008年 第2卷 第2期   页码 164-168 doi: 10.1007/s11708-008-0031-4

摘要： Correlation dimension as a tool to describe machinery condition is introduced. Vibration signals of the fan under different working conditions are analyzed using a threshold filtering algorithm based on the region relativity of the wavelet coefficients for reducing noise. The result shows that the characteristics of the signal could be preserved completely. The correlation dimension is able to identify conditions of the fan with faults compared with the normal condition, thereby providing an effective technology for condition monitoring and fault diagnosis of mechanical equipment.

关键词： effective technology     monitoring     mechanical equipment     relativity     Correlation    

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Interfacial heat transfer coefficient between metal and die during high pressure die casting process

GUO Zhipeng, XIONG Shoumei, CHO SangHyun, CHOI JeongKil

《机械工程前沿（英文）》 2007年 第2卷 第3期   页码 283-287 doi: 10.1007/s11465-007-0049-z

摘要： The present work focused on the determination of the interfacial heat transfer coefficient (IHTC) between metal and die during the high pressure die casting (HPDC) process. Experiments were carried out on an aluminum alloy, ADC12Z, using step shape casting so-called because of its shape. The IHTC was successfully determined by solving one of the inverse heat problems using the nonlinear estimation method first used by Beck. The calculation results indicated that the IHTC immediately increased after liquid metal was brought into the cavity by the plunger and decreased as the solidification process of the liquid metal proceeded. The liquid metal eventually solidified completely, a condition when the IHTC tended to be stable. Casting thickness played an important role in affecting the IHTC between the metal and die not only in terms of its value but also in terms of its change tendency. Also, under the test conditions, different change tendencies of the metal solid fraction were found between castings with different thicknesses and the die.

关键词： so-called     calculation     inverse     interfacial     aluminum    

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Wind tunnel test study on the wind pressure coefficient of claddings of high-rise buildings

Yong QUAN, Yi LIANG, Fei WANG, Ming GU

《结构与土木工程前沿（英文）》 2011年 第5卷 第4期   页码 518-524 doi: 10.1007/s11709-011-0128-4

摘要： The area-averaged most unfavorable wind pressure coefficients (MUWPCs) on various regions of building surfaces and the influence of the side ratio and the terrain category were studied based on wind tunnel test data of scale models of typical high-rise buildings with rectangular cross-sections. The negative area-averaged MUWPCs in the middle-height edge areas generally increased with an increasing / side ratio. The area-averaged MUWPCs can be well fitted with a function of the average area reduced by the square of the building depth, . In addition, no unique pattern was found for the effect of the terrain category on the MUWPCs.

关键词： side ratio     area-averaged pressure coefficients     cladding     terrain category    

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Loss coefficient of nitrogenous non-point source pollution under various precipitation conditions

CHENG Hongguang, HAO Fanghua, REN Xiyan, YANG Shengtian, XIONG Wen, LEI Shaoping

《环境科学与工程前沿（英文）》 2008年 第2卷 第2期   页码 230-235 doi: 10.1007/s11783-008-0043-7

摘要： In this study, calibrations of non-point source (NPS) pollution models are performed based on Black River basin historical real-time runoff data, sedimentation record data, and NPS sources survey information. The concept of NPS loss

关键词： information     concept     non-point     historical real-time     sedimentation    

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Correlation of chloride diffusion coefficient and microstructure parameters in concrete: A comparative

Yurong ZHANG, Shengxuan XU, Yanhong GAO, Jie GUO, Yinghui CAO, Junzhi ZHANG

《结构与土木工程前沿（英文）》 2020年 第14卷 第6期   页码 1509-1519 doi: 10.1007/s11709-020-0681-9

摘要： Permeability is a major indicator of concrete durability, and depends primarily on the microstructure characteristics of concrete, including its porosity and pore size distribution. In this study, a variety of concrete samples were prepared to investigate their microstructure characteristics via nuclear magnetic resonance (NMR), mercury intrusion porosimetry (MIP), and X-ray computed tomography (X-CT). Furthermore, the chloride diffusion coefficient of concrete was measured to explore its correlation with the microstructure of the concrete samples. Results show that the proportion of pores with diameters<1000 nm obtained by NMR exceeds that obtained by MIP, although the difference in the total porosity determined by both methods is minimal. X-CT measurements obtained a relatively small porosity; however, this likely reflects the distribution of large pores more accurately. A strong correlation is observed between the chloride diffusion coefficient and the porosity or contributive porosity of pores with sizes<1000 nm. Moreover, microstructure parameters measured via NMR reveal a lower correlation coefficient versus the chloride diffusion coefficient relative to the parameters determined via MIP, as NMR can measure non-connected as well as connected pores. In addition, when analyzing pores with sizes>50 µm, X-CT obtains the maximal contributive porosity, followed by MIP and NMR.

关键词： permeability     microstructure     NMR     MIP     X-CT    

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Performance of rolling piston type rotary compressor using fullerenes (C70) and NiFe

Ruixiang WANG,Yihao ZHANG,Yi LIAO

《能源前沿（英文）》 2020年 第14卷 第3期   页码 644-648 doi: 10.1007/s11708-017-0453-y

摘要： A novel way for a compressor to improve its coefficient of performance was proposed in this paper. Fullerenes (C70) and NiFe O nanocomposites were modified by span 80 and dispersed in refrigeration oil by solid grinding (SG). Besides, the tribological properties of the nanocomposites were investigated using a four ball friction tester. The results show that when the mass concentration of fullerenes nanocomposite is higher than 60 ppm and the concentration of nano-oil is 2 g/L, the friction coefficient decreases from 0.13 to 0.06 which means the wear is reduced. The coefficient of performance of the compressor under the air conditioning test condition can be raised by 1.23%.

关键词： rotary compressor     friction coefficient     nanocomposite materials     coefficient of performance     fullerenes (C70)    

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标题 作者 时间 类型 操作

Comparison between inhibitor and uncoupler for minimizing excess sludge production of an activated sludge process

CHEN Guowei, XI Pengge, XU Deqian, YU Hanqing

期刊论文

Co-application of energy uncoupling and ultrafiltration in sludge treatment: Evaluations of sludge reduction

An Ding, Yingxue Zhao, Zhongsen Yan, Langming Bai, Haiyang Yang, Heng Liang, Guibai Li, Nanqi Ren

期刊论文

RETRACTED ARTICLE: Momentum exchange coefficient for two jet flows mixing in a tee junction

期刊论文

Experimental study of heat transfer coefficient with rectangular baffle fin of solar air heater

Foued CHABANE,Nesrine HATRAF,Noureddine MOUMMI

期刊论文

A photolysis coefficient for characterizing the response of aqueous constituents to photolysis

David R. HOKANSON,Ke LI,R. Rhodes TRUSSELL

期刊论文

Effect of heat transfer coefficient of steam turbine rotor on thermal stress field under off-design condition

Jie GUO,Danmei XIE,Hengliang ZHANG,Wei JIANG,Yan ZHOU

期刊论文

Dimensionality reduction and prediction of soil consolidation coefficient using random forest coupling

Hai-Bang LY; Huong-Lan Thi VU; Lanh Si HO; Binh Thai PHAM

期刊论文

Developing the QSPR model for predicting the storage lipid/water distribution coefficient of organic

Miao Li, Jian Li, Yuchen Lu, Cenyang Han, Xiaoxuan Wei, Guangcai Ma, Haiying Yu

期刊论文

Heat transfer coefficient of wheel rim of large capacity steam turbines

SHI Jinyuan, DENG Zhicheng, YANG Yu, JUN Ganwen

期刊论文

Diagnosis method based on wavelet coefficient scale relativity correlation dimension for fault

GU Junjie, TIAN Jin, PENG Xuezhi

期刊论文

Interfacial heat transfer coefficient between metal and die during high pressure die casting process

GUO Zhipeng, XIONG Shoumei, CHO SangHyun, CHOI JeongKil

期刊论文

Wind tunnel test study on the wind pressure coefficient of claddings of high-rise buildings

Yong QUAN, Yi LIANG, Fei WANG, Ming GU

期刊论文

Loss coefficient of nitrogenous non-point source pollution under various precipitation conditions

CHENG Hongguang, HAO Fanghua, REN Xiyan, YANG Shengtian, XIONG Wen, LEI Shaoping

期刊论文

Correlation of chloride diffusion coefficient and microstructure parameters in concrete: A comparative

Yurong ZHANG, Shengxuan XU, Yanhong GAO, Jie GUO, Yinghui CAO, Junzhi ZHANG

期刊论文

Performance of rolling piston type rotary compressor using fullerenes (C70) and NiFe

Ruixiang WANG,Yihao ZHANG,Yi LIAO

期刊论文