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

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    

Large eddy simulation of turbulent buffet forces in flow induced vibration

XI Zhide, CHENG Bingde, LI Pengzhou

《能源前沿(英文)》 2008年 第2卷 第4期   页码 524-527 doi: 10.1007/s11708-008-0099-x

摘要: The pressure pulse filter and Smagorinsky sub-grid stress model of the Large Eddy Simulation (LES) are introduced. The fluid field in the annular plenum between the pressure vessel and the core barrel of the1:5 model in the second phase of Qinshan Nuclear Power Plant is simulated, and the distribution of the total pressure in the space and time domains is obtained. The results show that the Power Spectrum Density (PSD) of LES from the calculation and the test are in the same quantity order. Thus, the pressure of LES can be a load to stimulate the barrel vibration.

关键词: Spectrum Density     Smagorinsky sub-grid     vibration     calculation     Qinshan Nuclear    

Tripotassium citrate monohydrate derived carbon nanosheets as a competent assistant to manganese dioxide with remarkable performance in the supercapacitor

《化学科学与工程前沿(英文)》 2022年 第16卷 第3期   页码 420-432 doi: 10.1007/s11705-021-2065-7

摘要: Production cost, capacitance, and electrode materials safety are the key factors to be concerned about for supercapacitors. In this work, a type of carbon nanosheets was produced through the carbonization of tripotassium citrate monohydrate and nitric acidification. Subsequently, a well-designed manganese dioxide/carbon nanosheets composite was synthesized through hydrothermal treating. The carbon nanosheets served as the substrate for growing the manganese dioxide, regulating its distribution, and preventing it from inhomogeneous dimensions and severe agglomeration. Many manganese dioxide nanosheets grew vertically on the numerous functional groups generated on the surface of the carbon nanosheets during acidification. The synergistic combination of carbon nanosheets and manganese dioxide tailors the electrochemical performance of the composite, which benefits from the excellent conductivity and stability of carbon nanosheets. The carbon nanosheets derived from tripotassium citrate monohydrate are conducive to the remarkable performance of manganese dioxide/carbon nanosheets electrode. Finally, an asymmetric supercapacitor with active carbon as the cathode and manganese dioxide/carbon nanosheets as the anode was assembled, achieving an outstanding energy density of 54.68 Wh·kg–1 and remarkable power density of 6399.2 W·kg–1 superior to conventional lead-acid batteries. After 10000 charge-discharge cycles, the device retained 75.3% of the initial capacitance, showing good cycle stability. Two assembled asymmetric supercapacitors in series charged for 3 min could power a yellow light emitting diode with an operating voltage of 2 V for 2 min. This study may provide valuable insights for applying carbon materials and manganese dioxide in the energy storage field.

关键词: carbon nanosheets     manganese dioxide     asymmetric supercapacitors     energy density     power density    

Investigation on available wind energy at Tungku beach

M. G. YAZDANI, M. A. SALAM

《能源前沿(英文)》 2012年 第6卷 第3期   页码 275-279 doi: 10.1007/s11708-012-0194-x

摘要: In this paper, wind velocities and directions (sea and land) are recorded in different days and times. The data collected were compared with the weather data from the Brunei Darussalam Meteorological Service (BDMS) and the findings of other researchers and were found to be in good agreement. The potential of wind energy is predicted from the available data collected. The average generated power (forenoon and afternoon) is found to be 25 (mean) and 18 W (median), 101 (mean) and 73 W (median), 912 (mean) and 660 W (median), 10137 (mean) and 7331 W (median) for a rotor with a diameter of 2.5, 5, 15 and 50 m, respectively. The power density for wind farming is found to be 0.26 (mean) and 0.19 (median), 0.31 (mean) and 0.22 (median) for the rotor whose diameter is 2.5 and 50 m, respectively, while the average values are found to be 0.28 (mean) and 0.2 (median) for the rotor whose diameter is 5 and 15 m.

关键词: wind velocity     temperature     tower height     power density     Raleigh distribution     electrical power    

Mirror system based therapy for autism spectrum disorders

CHEN Wei, ZHANG Jing, DING Jun

《医学前沿(英文)》 2008年 第2卷 第4期   页码 344-347 doi: 10.1007/s11684-008-0065-3

摘要: This paper reviews the present theories and empirical research of autisms’ cognitive research and mirror systems and introduces a new hypothesis about the causes of autism spectrum disorders (ASD): autistic mirror neuron dysfunction hypothesis. ASD subjects show obvious lack of the activation of the mirror system during the task of observation or emotional cognition. It is significant to investigate the mirror system for revealing the causes of autism and it is also helpful for developing new ways to diagnose or treat this disorder.

关键词: emotional cognition     observation     activation     spectrum     empirical research    

Assessment of wind energy potential in Gaza Strip

Juma Yousuf ALAYDI

《能源前沿(英文)》 2011年 第5卷 第3期   页码 297-304 doi: 10.1007/s11708-010-0134-6

摘要: The analysis of collected wind data at two sites in the Gaza Strip, namely, Gaza City and Gaza International Airport in Rafah city, is presented. The two sites are candidates for remote area wind energy applications. The purpose of this paper is to present the results of the assessment of wind energy potential in the Gaza Strip in order to evaluate the wind regimes for installing wind energy conversion systems for power generation. The data on wind speed, direction and frequency distribution are used to analyze wind energy characteristics and availability at some stations in the Gaza Strip. The vertical extrapolation was based on the power-law expression, and the wind energy and potential have been estimated at the wind turbine hub height of approximately 50 m. Furthermore, the values of the Weibull parameters and are determined from summary statistics of wind resource. Consequently, the wind power is estimated by adoption of the Weibull distribution expression. Based on the results of this paper, sites are recommended for wind energy exploitation in the Gaza Strip.

关键词: wind data     wind resource assessment     wind power density     wind energy     the Weibull distribution and Weibull parameters    

Solar fuel from photo-thermal catalytic reactions with spectrum-selectivity: a review

Sanli TANG, Jie SUN, Hui HONG, Qibin LIU

《能源前沿(英文)》 2017年 第11卷 第4期   页码 437-451 doi: 10.1007/s11708-017-0509-z

摘要: Solar fuel is one of the ideal energy sources in the future. The synergy of photo and thermal effects leads to a new approach to higher solar fuel production under relatively mild conditions. This paper reviews different approaches for solar fuel production from spectrum-selective photo-thermal synergetic catalysis. The review begins with the meaning of synergetic effects, and the mechanisms of spectrum-selectivity and photo-thermal catalysis. Then, from a technical perspective, a number of experimental or theoretical works are sorted by the chemical reactions and the sacrificial reagents applied. In addition, these works are summarized and tabulated based on the operating conditions, spectrum-selectivity, materials, and productivity. A discussion is finally presented concerning future development of photo-thermal catalytic reactions with spectrum-selectivity.

关键词: photo-thermal catalysis     spectrum-selectivity     solar fuel     full-spectrum    

Detection of geosmin and 2-methylisoborneol by liquid-liquid extraction-gas chromatograph mass spectrum(LLE-GCMS) and solid phase extraction-gas chromatograph mass spectrum (SPE-GCMS)

MA Xiaoyan, CHEN Beibei, LI Qingsong, ZHANG Qiaoli, GU Guofen

《环境科学与工程前沿(英文)》 2007年 第1卷 第3期   页码 286-291 doi: 10.1007/s11783-007-0048-7

摘要: Two sample preparation methods were introduced and compared in this paper to establish a simple, quick and exact analysis of geosmin and 2-methylisoborneol. LC-18 column was employed in solid phase extraction (SPE), 1.0 mL of hexane was adopted in liquid-liquid extraction (LLE), and the extracts were analyzed by gas chromatograph mass spectrum (GCMS) in selected ion mode. Mean recoveries of SPE were low for 2-methylisoborneol (2-MIB) and geosmin (GSM) with values below 50%. For LLE, the recoveries were satisfyingly above 50% for 2-MIB and 80% for GSM. Detection limits of the LLE method were as low as 1.0 ng/L for GSM and 5.0 ng/L for 2-MIB. A year-long investigation on odor chemicals of drinking water in Shanghai demonstrated that in the summer, there was a serious odor problem induced by a high concentration of 2-MIB. The highest concentration of 152.82 ng/L appeared in July in raw water, while GSM flocculation was minimal with concentrations below odor threshold.

关键词: summer     flocculation     simple     Shanghai     spectrum    

Evaluation of the wind energy potential of two south west sites in Nigeria

Olaleye M. AMOO

《能源前沿(英文)》 2012年 第6卷 第3期   页码 237-246 doi: 10.1007/s11708-012-0201-2

摘要: Wind resource assessment is a crucial first step in gauging the potential of a site to produce energy from wind turbines. In this paper, the wind energy potential of Abeokuta (07°03'N, 03°19'E) and Ijebu-Ode (06°47'N, 03°58'E), two south west sites in Nigeria were examined. Twenty years (1990–2010) of monthly mean wind data from a 10 m height were subjected to two-parameter Weibull analysis and other statistical analyses. The results show that the average annual mean wind speed variation for Abeokuta ranges from 2.2 to 5.0 m/s. For Ijebu-Ode, it ranges from 2.0 to 5.0 m/s. The wind power density variation based on the Weibull analysis ranges from 4.26 to 24.51 W/m for Abeokuta and from 8.54 to 76.46 W/m for Ijebu-Ode. Ijebu-Ode was found to be the better of the two sites in terms of annual variation of mean wind speed.

关键词: wind potential     wind speed     wind power density     wind gust     turbulence intensity     Nigeria    

基于纳米孔渗透获取盐度梯度能量发电的可行性研究 Article

王樟新, Li Wang, Menachem Elimelech

《工程(英文)》 2022年 第9卷 第2期   页码 51-60 doi: 10.1016/j.eng.2021.02.016

摘要:

随着具有离子选择性纳米通道的新型材料的研发,一种获取盐度梯度(蓝色)能量的新技术被提出,即纳米孔发电机(NPG)。在本研究中,我们对膜片尺度和组件尺度的NPG运行的实际性能进行了全面分析。结果表明,虽然NPG 膜片可以在理想条件下产生超高的功率密度,但由于浓度极化效应,实际运行中NPG膜片上产生的功率密度很难达到10 W·m−2。对于组件尺度的NPG运行,我们估算了功率密度和可提取比能(即使用单位总体积工作溶液可产生的能量),并基于浓度极化与高浓度溶液和低浓度溶液的混合程度之间的相互作用,阐明运行条件对这两个指标的影响。此外,我们还开发了一个用来评估NPG 系统可行性的模型框架。结果表明,对于使用海水与河水的NPG 系统,总可提取比能非常低(约0.1 kW·h·m−3),且受到系统运行能耗的影响(特别是海水和河水溶液的汲取与预处理能耗)。总的来说,NPG系统产生的净可提取比能(< 0.025 kW·h·m−3)和净功率密度(< 0.1 W·m−2)非常低。我们的研究重点指出了NPG在现实运行中存在极大的局限性,进而对NPG作为一种蓝色能量收集技术的可行性提出了质疑。

关键词: 纳米孔发电机     盐度梯度(蓝色)能量     功率密度     可提取比能    

Contact fatigue life prediction of a bevel gear under spectrum loading

Pan JIA, Huaiju LIU, Caichao ZHU, Wei WU, Guocheng LU

《机械工程前沿(英文)》 2020年 第15卷 第1期   页码 123-132 doi: 10.1007/s11465-019-0556-8

摘要: Rolling contact fatigue (RCF) issues, such as pitting, might occur on bevel gears because load fluctuation induces considerable subsurface stress amplitudes. Such issues can dramatically affect the service life of associated machines. An accurate geometry model of a hypoid gear utilized in the main reducer of a heavy-duty vehicle is developed in this study with the commercial gear design software MASTA. Multiaxial stress–strain states are simulated with the finite element method, and the RCF life is predicted using the Brown–Miller–Morrow fatigue criterion. The patterns of fatigue life on the tooth surface are simulated under various loading levels, and the RCF curve is numerically generated. Moreover, a typical torque–time history on the driven axle is described, followed by the construction of program load spectrum with the rain flow method and the Goodman mean stress equation. The effects of various fatigue damage accumulation rules on fatigue life are compared and discussed in detail. Predicted results reveal that the Miner linear rule provides the most optimistic result among the three selected rules, and the Manson bilinear rule produces the most conservative result.

关键词: bevel gear     rolling contact fatigue (RCF)     multiaxial fatigue criterion     load spectrum     damage accumulation rule    

石墨烯基超级电容器的发展现状与战略研究

陈静,郭红霞,毛卫国,刘剑洪,付永胜,欧阳晓平

《中国工程科学》 2018年 第20卷 第6期   页码 75-81 doi: 10.15302/J-SSCAE-2018.06.012

摘要:

超级电容器兼具普通电容器和化学电池的优点,具有功率密度高、可快速充放电、循环寿命长等显著优势。电极材料是发展具有优异性能超级电容器的关键材料。石墨烯凭借其优异的力学、电学、热学等性能成为超级电容器理想的电极材料。本文首先基于对石墨烯基超级电容器相关学术论文、专利的统计分析,讨论了石墨烯基超级电容器的发展现状与方向;其次,简要阐述了石墨烯基超级电容器在国内的产业发展现状,讨论了石墨烯基超级电容器未来发展所面临的难点与挑战,并在此基础上提出了未来发展的方向与建议。

关键词: 石墨烯     超级电容器     电极材料     功率密度     能量密度    

一种新的通信抗干扰技术体制:预编码跳码扩谱

姚富强,张毅

《中国工程科学》 2011年 第13卷 第10期   页码 69-75

摘要:

基于常规直扩体制的不足,笔者分析了跳码扩谱的必要性,提出和研究了一种新的预编码跳码扩谱通信抗干扰技术体制,重点讨论了预编码跳码扩谱的基本原理与自编码跳码扩谱的异同点、关键技术等,最后分析了其基本性能。该体制和性能已在实际中得到初步验证。

关键词: 通信抗干扰     直接序列扩谱     预编码跳码扩谱     自编码跳码扩谱    

一类高维随机系统的小波分析

夏学文

《中国工程科学》 2004年 第6卷 第11期   页码 43-46

摘要:

利用小波分析研究了线性随机系统在小波变换下的平均功率、稠度、小波展开及展开系数的相关性等。

关键词: 随机系统     小波分析     平均功率     稠度     相关性    

Review of recent advances of polymer based dielectrics for high-energy storage in electronic power devices

Wenjie Sun, Jiale Mao, Shuang Wang, Lei Zhang, Yonghong Cheng

《化学科学与工程前沿(英文)》 2021年 第15卷 第1期   页码 18-34 doi: 10.1007/s11705-020-1939-4

摘要: Polymer-based dielectric capacitors are widely-used energy storage devices. However, although the functions of dielectrics in applications like high-voltage direct current transmission projects, distributed energy systems, high-power pulse systems and new energy electric vehicles are similar, their requirements can be quite different. Low electric loss is a critical prerequisite for capacitors for electric grids, while high-temperature stability is an essential pre-requirement for those in electric vehicles. This paper reviews recent advances in this area, and categorizes dielectrics in terms of their foremost properties related to their target applications. Requirements for polymer-based dielectrics in various power electronic equipment are emphasized, including high energy storage density, low dissipation, high working temperature and fast-response time. This paper considers innovations including chemical structure modification, composite fabrication and structure re-design, and the enhancements to material performances achieved. The advantages and limitations of these methods are also discussed.

关键词: dielectric capacitors     polymer-based dielectrics     energy density     dielectric loss     working temperature     frequency response    

标题 作者 时间 类型 操作

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

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

期刊论文

Large eddy simulation of turbulent buffet forces in flow induced vibration

XI Zhide, CHENG Bingde, LI Pengzhou

期刊论文

Tripotassium citrate monohydrate derived carbon nanosheets as a competent assistant to manganese dioxide with remarkable performance in the supercapacitor

期刊论文

Investigation on available wind energy at Tungku beach

M. G. YAZDANI, M. A. SALAM

期刊论文

Mirror system based therapy for autism spectrum disorders

CHEN Wei, ZHANG Jing, DING Jun

期刊论文

Assessment of wind energy potential in Gaza Strip

Juma Yousuf ALAYDI

期刊论文

Solar fuel from photo-thermal catalytic reactions with spectrum-selectivity: a review

Sanli TANG, Jie SUN, Hui HONG, Qibin LIU

期刊论文

Detection of geosmin and 2-methylisoborneol by liquid-liquid extraction-gas chromatograph mass spectrum(LLE-GCMS) and solid phase extraction-gas chromatograph mass spectrum (SPE-GCMS)

MA Xiaoyan, CHEN Beibei, LI Qingsong, ZHANG Qiaoli, GU Guofen

期刊论文

Evaluation of the wind energy potential of two south west sites in Nigeria

Olaleye M. AMOO

期刊论文

基于纳米孔渗透获取盐度梯度能量发电的可行性研究

王樟新, Li Wang, Menachem Elimelech

期刊论文

Contact fatigue life prediction of a bevel gear under spectrum loading

Pan JIA, Huaiju LIU, Caichao ZHU, Wei WU, Guocheng LU

期刊论文

石墨烯基超级电容器的发展现状与战略研究

陈静,郭红霞,毛卫国,刘剑洪,付永胜,欧阳晓平

期刊论文

一种新的通信抗干扰技术体制:预编码跳码扩谱

姚富强,张毅

期刊论文

一类高维随机系统的小波分析

夏学文

期刊论文

Review of recent advances of polymer based dielectrics for high-energy storage in electronic power devices

Wenjie Sun, Jiale Mao, Shuang Wang, Lei Zhang, Yonghong Cheng

期刊论文