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Load shedding scheme for an interconnected hydro-thermal hybrid system with SMES

D. TYAGI, Ashwani KUMAR, Saurabh CHANANA

《能源前沿（英文）》 2012年第6卷第3期页码 227-236 doi: 10.1007/s11708-012-0198-6

摘要： The frequency of the power system varies based on the load pattern of the consumers. With continuous increase in the load, the frequency of the system keeps decreasing and may reach its minimum allowable limits. Further increase in the load will result in more frequency drop leading to the need of load shedding, if excess generation is not available to cater the need. This paper proposed a methodology in a hybrid thermal-hydro system for finding the required amount of load to be shed for setting the frequency of the system within its minimum allowable limits. The load shedding steps were obtained based on the rate of change of frequency with the increase in the load in both areas. The impact of superconducting magnetic energy storage (SMES) was obtained on load shedding scheme. The comparison of the results was presented on the two-area system.

关键词： critical load frequency response load shedding multi-area system rate of change of frequency superconducting magnetic energy storage (SMES) device

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Load shedding scheme for the two-area system with linear quadratic regulator

D. TYAGI, Ashwani KUMAR, Saurabh CHANANA

《能源前沿（英文）》 2013年第7卷第1期页码 90-102 doi: 10.1007/s11708-012-0224-8

摘要： The power system is prone to many emergency conditions which may lead to emergency state of operation with decay in the system frequency. The dramatic change in the frequency can result in cascaded failure of the system. In order to avoid power system collapse, load shedding (LS) schemes are adopted with the optimal amount of load shed. This paper proposed a methodology in a two-area thermal-thermal system for finding the required amount of load to be shed for setting the frequency of the system within minimum allowable limits. The LS steps have been obtained based on the rate of change of frequency with the increase in load in steps. A systematic study has been conducted for three scenarios: the scheme with a conventional integral controller; the scheme with a linear quadratic regulator (LQR); and the scheme with an LQR and superconducting magnetic energy storage devices (SMES). A comparison of the results has been presented on the two-area system.

关键词： critical load frequency response load shedding (LS) multi-area system rate of change of frequency linear quadratic regulator (LQR) superconducting magnetic energy storage devices (SMES)

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Influence of infiltration on energy consumption of a winery building

Hejiang SUN, Qingxia YANG

《能源前沿（英文）》 2014年第8卷第1期页码 110-118 doi: 10.1007/s11708-013-0293-3

摘要： With the wide use of light steel structure in industrial buildings, some problems such as air leakage, water dripping and condensation and so forth occur during the construction and operation phases. Through the onsite testing of a winery building in Huailai County, Hebei Province in China, the influence of infiltration on energy consumption in industrial buildings was studied. The pressurization test method and moisture condensation method were used to test the infiltration rates. The results show that the winery building is twice as leaky as normal Chinese buildings and five times as leaky as Canadian buildings. The energy use simulation demonstrates that the reduction of the infiltration rate of the exterior rooms to 1/3 and the interior rooms to 1/2 could help decrease a total energy consumption of approximately 20% and reduce a total energy cost of approximately $ 225000. Therefore, it has a great potential to reduce the energy consumption in this type of buildings. Enforcement of the appropriate design, construction and installation would play a significant role in improving the overall performance of the building.

关键词： industrial building air change rate pressurization test method moisture condensation method energy cost

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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

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Reduction of wastewater toxicity and change of microbial community in a hydrolysis acidification reactor

Xin Xing, Yin Yu, Hongbo Xi, Guangqing Song, Yajiao Wang, Jiane Zuo, Yuexi Zhou

《环境科学与工程前沿（英文）》 2018年第12卷第6期 doi: 10.1007/s11783-018-1055-6

摘要：

HAP was verified to reduce the toxicity of TMP wastewater effectively.

Actual TMP wastewater was fed in HAP with different dilution ratios for 240 days.

Formaldehyde, 2-ethylacrolein, TMP and 2-ethylhexanol were all greatly removed.

Firmicutes became the dominant phylum (the abundance increased to 57.08%).

关键词： Trimethylolpropane wastewater Hydrolysis acidification process Toxicity Oxygen uptake rate 16S rDNA

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基于语料库的小学英语认识率及教材选词策略研究 Article

Wen-yan XIAO,Ming-wen WANG,Zhen WENG,Li-lin ZHANG,Jia-li ZUO

《信息与电子工程前沿（英文）》 2017年第18卷第3期页码 362-372 doi: 10.1631/FITEE.1601118

摘要：词汇是语言学习中的基础任务之一，是语言学习者发展听、说、读、写语言技能的重要前提，在教材课文选择中要覆盖哪些词汇，是教材编写中的基本问题。针对这个问题，本文利用网络爬虫等技术构建英文网页语料库(EWC)，并进行词频分析；将EWC与英国国家语料库(BNC)进行词频对比分析，发现词频分布具有一定的时效性。通过我国目前小学英语教材词汇表与EWC, BNC, SUBTLEX-US，CBBC词频表的对比分析，给出了小学生在一般阅读时的英语词汇认识率，分析结果表明，小学生对一般语域和特定语域的词汇认识率都相对较低。通过这些定量分析，本文为我国小学英语教材编写提出了一些词汇选择方面的策略。

关键词：语料库；小学英语；认识率；词频；覆盖率

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Climate change and China’s mega urban regions

Chaolin GU, Sunsheng HAN

《结构与土木工程前沿（英文）》 2010年第4卷第4期页码 418-430 doi: 10.1007/s11709-010-0075-5

摘要： China’s mega urban regions are focal points of economic development and environmental concerns. This paper positions four mega urban regions (i.e., the Yangtze River Delta, the Pearl River Delta, the Bohai Bay Area, and the South-eastern Fujian Province) along China’s coast into the national economy and elaborates their development challenges and planning innovations. Mega urban regions in China are spatial consequences of rapid economic transition. They deserve close scrutiny and demands for innovative planning responses in order to maintain their key role in driving economic growth but limiting their greenhouse gas emission.

关键词： climate change mega urban region urban planning

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Tackling climate change and promoting the energy revolution

Xiangwan DU

《能源前沿（英文）》 2018年第12卷第3期页码 338-343 doi: 10.1007/s11708-018-0535-5

摘要：

Following the Paris Agreement, green and low-carbon development has entered into a new stage. China’s international responsibility to combat climate change is consistent with the inherent sustainable development needs of the country. In this paper, the reasonability of China’s Intended Nationally Determined Contributions (INDC) is examined and the fact that low-carbon development can lead to modernization is demonstrated based on data analysis of energy economics from developed countries. Considering the fact that such an energy revolution forms the basis for China’s low-carbon transition, a roadmap of the China’s energy utilization is presented. Based on research results from the Chinese Academy of Engineering, the three historical stages of China’s energy structure reform are analyzed. Promoting a low-carbon transition through an energy revolution is a long-term and arduous process that requires a genuine transformation of development outlook and patterns. By empirically analyzing situations at home and abroad, a conclusion is made that economic development and a low-carbon transition can be achieved simultaneously; specifically, low-carbon development fosters new points of economic growth and gives rise to different development paths.

关键词： climate change Paris Agreement low-carbon transition energy revolution

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Large Scale Infrastructure Projects: The Art of Project or Change Management?

Geert Letens,Kurt Verweire,Peter De Prins

《工程管理前沿（英文）》 2016年第3卷第3期页码 197-202 doi: 10.15302/J-FEM-2016033

摘要： Although it is generally understood that change is a fundamental component of managing projects in the construction industry in general and an inevitable challenge for large scale infrastructure project in particular, there has been little to no attention in the literature to understand change in this context from a more holistic perspective. For this purpose, this work looks at change through the eyes of a framework of six batteries of change that seem essential to charge an organization’s capabilities for change. The framework brings together the expertise of four specialists that all have developed their insights over many years of study and practice, and has been validated through an extensive review of the management literature on organization development and change. Reflections on the application of this model in the construction industry and in large scale infrastructure projects demonstrate that energizing organizations to successfully deal with change goes beyond the traditional techniques of managing change from a program or project management perspective. Assessing the six batteries of change in this context can help organizations to develop capabilities for change that build change energy by balancing formal/rational methods with informal/emotional interventions at both a local (department/subproject) and global (business) level.

关键词： large scale project management organization development and change batteries of change model

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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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SEQUESTERING ORGANIC CARBON IN SOILS THROUGH LAND USE CHANGE AND AGRICULTURAL PRACTICES: A REVIEW

《农业科学与工程前沿（英文）》 2023年第10卷第2期页码 210-225 doi: 10.15302/J-FASE-2022474

摘要：

● Either increasing C input to or reducing C release from soils can enhance soil C sequestration.

关键词： agroecosystems climate change negative emissions technology net zero

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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）》 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 NH_3, 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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Challenges and countermeasures of urban water systems against climate change: a perspective from China

《环境科学与工程前沿（英文）》 2023年第17卷第12期 doi: 10.1007/s11783-023-1756-3

摘要：

● Urban water systems are challenged by climate change.

关键词： Climate change Urban water system Resilience Adaptation Mitigation

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Assessment of future climate change impacts on water-heat-salt migration in unsaturated frozen soil using

Hanli Wan, Jianmin Bian, Han Zhang, Yihan Li

《环境科学与工程前沿（英文）》 2021年第15卷第1期 doi: 10.1007/s11783-020-1302-5

摘要： Abstract • A model coupling water-heat-salt of unsaturated frozen soil was established. • Future temperature, precipitation, and evaporation increase in freeze–thaw period. • Soil water, heat, and salt transport are closely coupled during freeze–thaw period. • Freeze–thaw cycles and future climate change can exacerbate salinization. The transport mechanisms of water, heat, and salt in unsaturated frozen soil, as well as its response to future climate change are in urgent need of study. In this study, western Jilin Province in north-eastern China was studied to produce a model of coupled water-heat-salt in unsaturated frozen soil using CoupModel. The water, heat, and salt dynamics of unsaturated frozen soil under three representative concentration pathway (RCP) scenarios were simulated to analyze the effects of future climate change on unsaturated frozen soil. The results show that water, heat, and salt migration are tightly coupled, and the soil salt concentration in the surface layer (10 cm) exhibits explosive growth after freezing and thawing. The future (2020–2099) meteorological factors in the study area were predicted using the Statistical Downscaling Model (SDSM). For RCP2.6, RCP4.5, and RCP8.5 scenarios, future temperatures during the freeze–thaw period increased by 2.68°C, 3.18°C, and 4.28°C, respectively; precipitation increased by 30.28 mm, 28.41 mm, and 32.17 mm, respectively; and evaporation increased by 93.57 mm, 106.95 mm, and 130.57 mm, respectively. Climate change will shorten the freeze–thaw period, advance the soil melting time from April to March, and enhance water and salt transport. Compared to the baseline period (1961–2005), future soil salt concentrations at 10 cm increased by 1547.54 mg/L, 1762.86 mg/L, and 1713.66 mg/L under RCP2.6, RCP4.5, and RCP8.5, respectively. The explosive salt accumulation is more obvious. Effective measures should be taken to prevent the salinization of unsaturated frozen soils and address climate change.

关键词： Soil salinization Climate change Unsaturated frozen soil Water-heat-salt balance Soil environment change